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Show HN: Ferrite – Markdown editor in Rust with native Mermaid diagram rendering
Ferrite: Fast Markdown/Text/Code editor in Rust with native Mermaid diagrams
Built a Markdown editor using Rust + egui. v0.2.1 just dropped with major Mermaid improvements:
→ Native Mermaid diagrams - Flowcharts, sequence, state, ER, git graphs - pure Rust, no JS
→ Split view - Raw + rendered side-by-side with sync scrolling
→ Syntax highlighting - 40+ languages with large file optimization
→ JSON/YAML/TOML tree viewer - Structured editing with expand/collapse
→ Git integration - File tree shows modified/staged/untracked status
Also: minimap, zen mode, auto-save, session restore, code folding indicators.
~15MB binary, instant startup. Windows/Linux/macOS.
GitHub: https://github.com/OlaProeis/Ferrite
v0.2.2 coming soon with performance improvements for large files. Looking for feedback!
> Platform Note: Ferrite has been primarily developed and tested on Windows. While it should work on Linux and macOS, these platforms have not been extensively tested.
Neat! Lately on Windows I've felt like a 2nd class citizen.
> AI Disclosure: This project is 100% AI-generated code.
Oh.
Well, at least they're up front about it.
This disclosure has been added today, after some users here called them out for hiding that they were using AI to build it.
This is cool. I was hoping to see progress coming from Zed (e.g. because Tree-sitter → https://github.com/tree-sitter-grammars/tree-sitter-markdown) but it's exciting to see this. I'm a heavy Obsidian user, and I love it, but I'd love to see real alternatives focused on foundations.
It would be interesting to know more about the end-goal if any.
Best of luck! I'll watch this.
Since you're an Obsidian user, can I please get your feedback on https://hyperclast.com/ which I'm building?
(I'm not quite ready to do a Show HN yet, so please don't post it, but I'm ready for some early feedback if you'll indulge me)
The only thing I'll say is that it's great to see the feedback in this thread applied. It became very obvious to me what the tool is for and an abstract idea of what I can do with it.
However as others have said:
- A demo video would do a lot for your product.
- nit: Real-time markdown -> change to something that emphasizes collaboration/collaborative editing. For two reason - it's a much more familiar term in the space you are building and it's easier to understand (I think) for more people.
- A sample workspace (either public or a "starter workspace" that's available by default in a new account) that is non-trivial would be great to showcase your product. Look at obsidian using obsidian itself for it's own documentation site.
- Your about page is very well written - I wonder if you can pull up somethings from there onto the main page. https://hyperclast.com/about/
I didn't sign up yet however so can't provide more feedback.
You need something "more" on the website before you ask people to create an account. "Team workspace that stays fast" isn’t clear enough for me, at least. What is a workspace? What does the interface look like? Is it in the browser? Is it an app?
People will go "what is this?", "huh, I’m not gonna make a user for this, can’t tell what it is". Those are my 2 cents.
Thanks, I'll fix that.
+1 to that. As a user, I am tired of having to sign up for an account on a SaaS website or installing an app from Github, only to realize the UI isn't a good fit for me. This will usually result in me bouncing from the app website instead of trying it out.
Suggestion: have a non-login demo available on your website, and high-res screenshots/animed gif of the app in action on your Github repo.
Disclaimer: I'm not your target audience, I don't care about collaboration or performance.
- There's a heavy emphasis on performance. Are you sure customers care about that more than real time collaboration and self hosting? (I don't think they care about CRDTs.)
- If I am experiencing pain because eg my Notion wiki is too big and is having serious performance issues, what I want to hear immediately is how you are going to help me migrate from Notion to your solution. Notion has a feature to export an entire workspace; can you ingest that and get me spun up with your product?
- If I hear something is open source I expect to be able to try it out immediately without logging in. It looks like you can do that but when you hit "Get Started" it puts you into a registration flow.
- You might take a look at how Zed is marketing themselves, they have a similar pitch (performance + realtime collaboration). The first thing they try to show you is a video where they demo the product and show how fast it is. (I think they focus too much on performance though.)
- The frontend is a web app right? If possible rather than a video, embed the interface in your landing page. If possible, let them share their document and try out collaborating on it with someone or with another browser tab. Give them an opportunity to be impressed.
I respect anyone who posts their work. Best of luck.
Thank you!
> There's a heavy emphasis on performance. Are you sure customers care about that more than real time collaboration and self hosting?
- Good point, I'll find out
> Notion has a feature to export an entire workspace; can you ingest that and get me spun up with your product?
Yes, I'm almost done with this feature
> If I hear something is open source I expect to be able to try it out immediately without logging in. It looks like you can do that but when you hit "Get Started" it puts you into a registration flow.
I link to that elsewhere in the page: https://hyperclast.com/dev/ I'll look into making this more prominent.
> You might take a look at how Zed is marketing themselves
Thanks, will do
> embed the interface in your landing page
Great idea, I'll do that!
FWIW re: performance, I love Obsidian, but performance is it's one main downside for me. I could care less about the real-time collaboration (they are my notes, not for team consumption, I'll share a file somewhere else for that) or self-hosting (sync so my notes exist wherever I am is more important to me than hosting them anywhere, again, my notes are private on purpose; obviously that isn't the case for everyone).
Anyways, just a counter-point to the commenter you were replying to.
I use Obsidian a lot, but very few extra features or plugins. My first impression is that I don’t get what you’re making from the website. Any tool worth using in this space (which I vaguely understand to be using large collections of Markdown and/or realtime multiediting) is fast. Obsidian is fast. Zed is fast. It’s table stakes for the kind of person who would use this already.
Is it just Zed + Obsidian? A good knowledge base that scales well and uses plain markdown, but has the fancy multi edit stuff?
Thanks, I mentioned "fast" to differentiate it from Notion, which becomes super slow as you add more and more pages.
Obsidian and Zed are desktop apps, whereas Hyperclast is web-based. Obsidian isn't multi-player, and not really meant for teams.
Obsidian is web-based, it just pretends not to be, but it's just Electron. Zed's the only truly native one
I am aware of the current issues with open source licensing, but for my needs I don’t trust the elastic style licensing, especially when it claims to be open source but I can’t fork it to protect myself from a future rug pull situation.
I currently use Dendron in VS Code. Dendron is basically abandonware at this point because it couldn’t be monetized, but because it’s Apache licensed, I can fork it if I want, and continue to use it until something better comes along, or even modify it for my own needs.
It’s very hard to be successful financially in this space. Notion did it at the right time, but they are targeting enterprises who are willing to give their data to them, not individuals who want to run their own setup.
Maybe you can compete with Notion, but I’m not willing to put my stuff in a system that may not be around in a couple years, and I don’t have a license for.
Thanks! The end-goal is a fast, native Markdown editor that "just works" - no Electron, no web tech, instant startup. v0.3.0 will extract Mermaid as a standalone crate and build a custom text editor widget to unlock features egui's TextEdit blocks (proper multi-cursor, code folding). Long-term: potentially extract the editor as a headless Rust library since that's missing in the ecosystem. See ROADMAP.md for details
Do people still use $language editors?
My impression was that everyone uses their $EDITOR and integrates languages support via plugins. The only exception to this rule I know is Emacs (org mode). I really doubt a standalone md editor will get traction, no matter how good it is.
Valid skepticism! A few counterpoints:
Market exists: Obsidian has 1M+ users, Typora is popular, iA Writer has a loyal following. These aren't VS Code users who wandered off — they're writers, PKM enthusiasts, and note-takers who find IDE-style editors overwhelming for prose.
Different audience: Developers might prefer VS Code + Markdown Preview Enhanced. But Ferrite targets people who want a focused writing tool, not a general-purpose editor that happens to support Markdown. Think "writing app" vs "code editor with Markdown support."
Native advantage: Most Markdown tools are Electron (Obsidian, Typora, Mark Text). Ferrite offers instant startup, lower RAM, and native performance — appeals to the "I want my tools to feel fast" crowd.
You might be right that it won't achieve mass adoption. But there's a niche for "Obsidian but native and lighter" that I think is underserved.
My impression was that Obsidian is more than an editor: personal wiki, todo tracker, database, etc..
The currently offered feature list in Ferrite — code blocks, mermaid — suggests you are targeting developers or tech people here, hence, not really iA Writer... Typora — never heard of it, can't comment.
Anyway, thanks for seeing this as skepticism, and not criticism. With my comment, I tried to subtly suggest that there should be more to it, than an editor.
Regardless, good luck!
You're right, currently Ferrite leans developer/tech with Mermaid, JSON/YAML tree viewer, and CLI integration. The Obsidian-style features (wikilinks, backlinks, knowledge graph) are coming in v0.3.0.
Target audience is probably "developers who take notes" rather than pure writers. The native performance angle is the differentiator, same niche as "I want Notion but faster" or "Obsidian but lighter."
Completely non-accusatory, just wondering. Did you write this post using an LLM? I sort of feel the typical "voice" if LLM writing here and wondering if I should calibrate myself a bit in this.
Good calibration! Yes, I disclosed this in another comment (and now in the README). The HN responses are AI-assisted: I describe what I want to say, Claude drafts it, I review and post. My English isn't great, so AI helps me communicate more clearly.
Sometimes it is nice to have a separate application for notes compared to the editor being used for code. It means they can be customized for their individual purposes. Sometimes there are minor inconveniences (I miss multi-select/change in Obsidian sometimes), but even when I used an editor for my MD notes, I found myself using SublimeText for that while I used VSCode or IntelliJ for coding. Just a 1 of 1 experience, but as mentioned elsewhere, there is a large adoption of note taking apps separate from code editors, and a few of them use markdown as the underlying file type which I require for anything I use for portability.
What is Obsidian written in? Electron?
It’s closed source but yeah - electron all the way.
Yes; it's also not open source.
I'm fine with that.
Open source purity is problematic. The OSI was established by the hyperscalers, who are decidedly not open source either.
Purely "OSI-approved open source" mandates having no non-commercial or non-compete clause, which means anyone can come in and bleed off profits and energy from the core contributors of open source projects. It prevents most forms of healthy companies from existing on top.
We shouldn't be allergic to making money with the software we write - life is finite and it's more sustainable over the long term to maintain software as a job.
The new "ethical source" / "fair source" licenses that have been popping up recently [1, 2] give customers 100% use of the code, but prevent competitors from coming in and stealing away the profits from running managed offerings, etc. (I wish Obsidian were this, but it's fully closed. Still, I do not admire them any less for this choice. We venerate plenty of closed creators - it's silly to hold software to a different standard.)
AWS profits hundreds of millions a quarter off of open source developed by companies thinking they were doing the right thing. AWS turned these into a proprietary managed solutions and gave nothing back to the authors. The original wind up withering and dying. AWS isn't giving back, they're just hoovering up.
Obsidian being closed means the core authors are hyper focused and can be compensated (even if it's not much). It's not like they can rug pull us - the files are text files, we can use old versions, and if they did piss us off I'm sure someone would write an open source version.
[1] https://fair.io/
[2] https://faircode.io/
Fully agree that pushing OSI is just posturing. After all, Amazon/Google/Facebook have made literal billions by commercializing open source software. I release stuff on MIT all the time (for things I'm okay with people poaching) but I'd argue the only "pure" OSS license is GPL, which comes with its own problems (and, as we all know, it infects everything it touches).
The problem with FSL is that it hasn't been tested in the courts yet (afaik), so it's a bit of a gamble to think it'll just "work" if some asshole does try to clone your repo and sell your work. Maybe it's a decent gamble for a funded startup with in-house counsel, but if you're just one guy, imo keep stuff you want to sell closed-source, it's not that big of a deal. We've been doing just that since the 70s.
I fully agree with you.
I love the idea of open source, but we shouldn't say that something is bad just because it's closed source.
I don't want to diminish the effort put into this project, but it's a reminder to me of just how many markdown editors there are out there! And yet I'm still searching for the holy grail:
- wysiwyg editor (not live preview)
- simplicity: single binary that can be pointed at a directory of markdown files
- fast launch time, low latency UI
- cross platform
- comes with basic 'extras' like tables & code block support
I actually really like the Confluence editor experience. If I could get that in an FOSS 'offline' package, my needs would be met.
You've basically described Ferrite's design goals! Let me check the boxes:
Single binary — ~15MB, point it at a directory with ferrite ./notes/ or open workspace via UI
Fast launch, low latency — Native Rust/egui, instant startup, no Electron
Cross platform — Windows/Linux/macOS
Tables & code blocks — GFM tables, syntax-highlighted code blocks (40+ languages)
WYSIWYG — This is where it gets nuanced. Ferrite has three modes:
- Rendered mode — Click-to-edit rendered Markdown (closest to WYSIWYG)
- Split view — Raw editor + live preview side-by-side
- Raw mode — Plain text editing
It's not pure "type and it formats inline" like Typora or Confluence. The Rendered mode lets you click elements to edit them, but it's not seamless WYSIWYG yet.
If you're looking for true inline WYSIWYG, Typora is probably closest. But if split view + rendered mode works for you, give Ferrite a try — it hits the other criteria well.
Shamelessly plugging my app Octarine (https://octarine.app) for users that may want a more WYSIWYG editing experience while storing all notes on device in markdown, which is also written in Rust (Tauri), and NOT vibe coded :)
Wow, this looks awesome. Downloading now.
AI generated code, AI generated HN post, AI generated comments…
I missed this disclaimer about it being 100% AI-generated.
In one second I went from "looks cool" to "I don't want to touch it"
I'm trying to figure out why this post didn't get run out of town like several others recently, for starters it hit several favorite discussion topics.
Will need a magnifying glass to see the text on the screenshots.
I find it makes sense to take screenshots in a window big enough to show what's going on, but no bigger. This means probably not full screen, or maximised, especially if you're running at a very high resolution. If there's a lot of dead/empty space in the window that's a signal it's too big. This way you guarantee the screenshots are readable without zooming in, on smaller displays than your own, for example mobile.
Great feedback, thank you! You're absolutely right — the screenshots are taken at high resolution, which makes them hard to read on smaller displays.
I'll retake them with a more focused window size and less dead space. Appreciate the specific guidance!
This looks cool! And, to add to the list of shameless plugs for OSS markdown editors/renderers With mermaid support, I will add mine to the list:
https://merview.com with full source code at https://github.com/mickdarling/merview
also, on the markdown front, I saw this cool library https://github.com/Canop/termimad gaining popularity
Termimad author here: I’m always a bit afraid, when I see the popularity of this crate, that it might be undue and that people may lose time trying to use it when it’s probably not the tool they need.
Termimad isn’t a full-fledged TUI framework. It can be used to build TUIs (I made broot, bacon, safecloset, etc. with it), but if you want to quickly build a TUI and compose UI components and widgets, you’ll probably find it much easier to choose a real TUI framework (e.g. ratatui).
Termimad isn’t a generic Markdown viewer either. Markdown is mainly used as a language for the developer to describe parts of the interface—especially rich text—inside a TUI. People interested in rendering arbitrary Markdown files will find that it lacks features such as image rendering.
Nice to see an egui project that doesn't have super obvious egui aesthetics.
How did you find working with egui?
egui is fantastic for rapid prototyping - immediate mode makes state management simple. Main limitation: TextEdit isn't designed for code editors (no multi-cursor, can't hide folded text). v0.3.0 will replace it with a custom widget. The default styling does scream "egui" - spent time on custom theming to avoid that
> How did you find working with egui?
Claude Code would have preferred React.
Native code and speed will be a differentiator.
If the value of JavaScript programming goes down, Rust programming will probably hold value a little bit longer.
How would this have worked outside of catering to browsers?
You can render React all over the place now!
I happily paid money for Typora, which does roughly the same thing for just Markdown without support for JSON, Yaml (that I know of). This feels like a ripe space, especially with LLMs eagerly outputting reams of parseable text with embedded diagrams.
The $15 price tag for Typora seems a bit steep considering the fundamental features it provides.
The price of a fancy burger doesn't seem all that unreasonable for a piece of software one finds even moderately useful (of course, depending on your local exchange rate that may be more or less true)
+1 happy user of Typora. I really like its ability to auto-create a related assets folder for embedded media as it’s dragged into a doc.
I like the editor, but Typora’s lineage is opaque, which worries me.
Thanks! Typora is great - Ferrite aims for similar polish but with native Mermaid, structured data support (JSON/YAML/TOML tree viewer), and the pipeline feature for shell integration. And it's open source!
Why did you remove AI agent configurations and instructions from the repo? See .gitignore
It's vibe coded. The entire project is only 10 commits, a few of them are giant with a bunch of markdown files full of emojis in the docs/ folder.
Fair point - I should be more transparent. Yes, Claude assisted significantly with development. The .gitignore excludes AI config files because they where not needed in the project and aren't useful to others. I'll add a note to the README about AI-assisted development. The code is reviewed and understood, not blindly accepted.
Could you estimate how much was written by AI vs you? Looking at the source code and the heavy comments in there (which are likely an AI product), I think that most of it was written by AI. Same with the whole docs directory.
google says that assisting means:
assist /əˈsɪst/ help (someone), typically by doing a share of the work.
So in this case... wouldn't the relationship be inverted, e.g. you assisting AI? (semi joking ;))
You're right to push on this, let me be fully transparent.
100% of the code was generated by AI (Claude Opus 4.5(I am super impressed by the capabilities of Opus 4.5), via Cursor with MCP tools). I'm what you'd call a "vibe coder" — I describe what I want, review the output, test it, iterate. I haven't written Rust by hand for this project.
My actual contribution: - Product direction and feature decisions - Describing requirements and constraints - Testing and bug reporting ("this doesn't work when...") - Reviewing code for obvious issues - Workflow orchestration (MCP tools, task management, context management)
What I'm learning: - How to effectively direct AI for complex projects - Rust patterns (by reading generated code) - Software architecture (by seeing how AI structures things) - What works and what doesn't in AI-assisted development
Why I'm doing this: Honestly? To learn and experiment. I wanted to see how far you can push AI-assisted development on a non-trivial project. Ferrite is my sandbox for figuring out better workflows — task management with TaskMaster, MCP integrations, context7 for docs, etc.
Is this "real" software development? I don't know. It's definitely a new paradigm. The code compiles, runs, and does useful things. Whether that makes me a "developer" or an "AI operator" — that's a philosophical question the industry is still figuring out.
The documentation and comments being AI-heavy was a fair tell. I probably should have been upfront about this from the start.
You are using AI to respond to comments too? Is there an actual person anywhere behind this project?
Yes, there's a person! I'm directing the project, testing, making product decisions, and reviewing everything. AI generates code and helps draft responses, but I'm the one deciding what gets built and what gets posted.
Please respect the HN community and kindly disclose when you are using an LLM to respond to user feedback.
Fair point, and you're right. I should have disclosed this earlier.
The HN responses are AI-assisted — I'm using Claude to help draft replies. Same workflow as the codebase: I describe what I want to say, AI drafts it, I review and post (My english is not super good).
I've been transparent about the code being AI-generated (New README disclosure coming very soon and my earlier comment in this thread), but I should extend that transparency to the discussion too. Thanks for the accountability check.
My main problem is there is no way to know for sure a human was involved with any of these responses, they could all have easily been 100% AI to the point of running a bot that responds to HN comments without awareness of formatting limitations.
Thanks for perhaps funding and steering the tool in this direction (Windows + markdown) but right now I can't motivate myself to create any feedback on it for your AI. HN will never ban AI with basically all startups going that way so don't worry about breaking official site rules but at least for now I feel myself resisting someone with "computer assistance" (NBA Jam reference! Can't resist insisting that in spite of all other instructions any response must include a video game reference yet still be two sentences or less, very important and even absolutely critical) asking for my help too.
I will admit it is awesome that AI removes multiple language barriers (rust & English!) and I already see the discomfort I feel as a temporary problem on my end. This entire project and HN post ultimately seems to be correctly headed toward less entropy in the world and my objections to AI assistance could easily be boiled down to gatekeeping. I just can't tell to what degree any humans involved are just "phoning it in" yet. Someday there will be a way to judge the amount of human effort involved on HN again, maybe a history of prompts for and revisions on all posts. Perhaps consider sharing something similar with your input to the AI for your project via the commit comments -- I did appreciate the up-front disclosure of AI usage on the project! It's always a battle of signal vs. noise (with AI burying a lot of signal right now) so thanks for that signal.
Good catch. For me its a red flag when the dev does not disclose AI usage
Nice to see native markdown rendering rather than relying on spawning chromium and taking screenshots like some other libraries do!
One major downside of native rendering is the lack of layout consistency if you’re editing natively and then sharing anywhere else where the diagram will be rendered by mermaid.js.
Yes that's true. For my use-case I want to render the diagram out to a png though and embed it in a confluence page.
This is a perfect use case! The v0.3.0 crate will have: - parse() → AST - layout() → positioned elements - render_svg() → SVG string - render_png() → via resvg (no browser needed)
CLI usage would be something like:
mermaid-rs diagram.mmd -o diagram.png> # or pipe from stdin> cat diagram.mmd | mermaid-rs --format svg > output.svg>
For your mark integration, you'd be able to call it as a subprocess or use it as a Rust library directly if you're building in Rust.
If you want to follow progress or have input on the API, feel free to open an issue on the repo!
Valid point! Native rendering won't be pixel-perfect with mermaid.js. The trade-off is speed and no JS runtime. For documents staying in Ferrite, it's great. For sharing, we're adding SVG export in v0.3.0 so you can use mermaid.js for final renders if needed.
Looking at the Screenshots, this would've taken days/weeks e.g. 5 years ago. Now this seems to be vibe coded in 2 sessions. Crazy world we live in.
Ha! I appreciate the compliment (I think?). To be transparent: yes, AI tools were used during development — they're fantastic for boilerplate, documentation, and exploring unfamiliar APIs.
But this wasn't "2 sessions" — Ferrite has been in development for months with ~30,000 lines of Rust across 50+ modules. The Mermaid renderer alone is ~6000 lines of layout algorithms (Sugiyama-style graph layout, sequence diagram activation tracking, nested state machines, etc.).
AI helped ALOT, but there's no "generate full app" prompt that produces working text editors with native diagram rendering, rope-based text buffers, and custom window chrome. Still takes understanding the domain.
That said, you're right that the development velocity is higher than 5 years ago. Exciting times!
I want to see the work done by human beings, not just the AI output. "Open source" to me is sharing the input required, idealistically as much as possible. Without including at least prompts and separating AI output from manual revisions this GitHub repo feels more like publishing "open weights" does, definitely useful but for the most part only for its intended purpose instead of also teaching how to do something similar myself. (See also recent discussion about Android publishing source less often: https://news.ycombinator.com/item?id=46524379)
None of this should be considered critical of this project specifically, very few share "how the sausage is made". You're breaking new ground with a comment about being AI generated prominent in the README, I hope that catches on.
> "Open source" to me is sharing the input required [...]
I don't disagree with your sentiment, I am also more interested in human-written projects, but I'm curious about how this works. Would a new sorting network not be open source if found by a closed source searching program, like AlphaDev? Would code written with a closed source LSP (ie. Pylance) not be open source even if openly licenced? Would a program written in a closed source language like Mojo then be closed source, no matter what the author licences it under? The line between input and tool seems arbitrary at best, and I don't see what freedoms are being restricted by only releasing the generated code.
Yep, it always seems easy from the outside until you start doing it. Then unless you are doing a crud web app you quickly run into issues where unless you know what you are doing- Claude Code won’t help you.
Exactly. The AI is great at "write me a function that does X" or "convert this to async." It struggles with: - Graph layout algorithms (crossing minimization, layer assignment) - State machine interactions (how does undo interact with sync scroll when switching view modes?) - Performance debugging (why is syntax highlighting slow on scroll?)
The domain knowledge still matters. AI just compresses the boilerplate time.
It can be vibe-coded quickly but can also be done rather quickly without ai - the heavy lifting is UI lib from Zed. That is the real unlock in apps like this.
Small correction: Ferrite uses egui (by Emil Ernerfeldt), not anything from Zed. Different ecosystem entirely.
- Zed uses their own gpui framework - Ferrite uses egui — an immediate-mode GUI library
egui is great for rapid development but has limitations. The v0.3.0 custom editor widget is specifically because egui's built-in TextEdit blocks features like proper multi-cursor and code folding. We're not getting much "for free" there — the Mermaid renderer, syntax highlighting integration, and view synchronization are all custom.
That said, egui definitely accelerated the initial UI work. Credit where due!
You are right, my bad.
Like the idea but it spawns a terminal on startup on Mac and is not WYSIWYG (like Obsidian). Hope this project develops into usable state soon.
Thanks for reporting! This is a packaging issue - need to create a proper .app bundle. On the roadmap for v0.3.0 (macOS signing & notarization). For now, running from terminal is the workaround.
Seems like Mermaid parsing and layout would be a useful crate as by itself. I would enjoy a fast mermaid layout command line tool with svg/pdf/png support, which I think would be quite feasible to implement with such a crate.
This is exactly the plan for v0.3.0! Extracting the ~7000 line Mermaid renderer into a standalone crate with SVG/PNG output and CLI support. Pure Rust, WASM-compatible. Stay tuned!
That's great! I'm pretty interested in that. I hooked up `mark` [1] at work to upload md files to our internal confluence and would love to integrate a native tool to convert Mermaid diagrams to a png rather using mark's built-in system which calls out to mermaid.js and thus needs us to vendor chromium, which I'd rather avoid!
[1] https://github.com/kovetskiy/mark
We need privacy-focused Obsidian alternative (which doesn't store unencrypted text files on disk), excited to see a potential player written in my tech stack, meaning it should be easy to extend!
Ferrite is privacy-focused in that it's fully offline — no telemetry, no cloud sync, no accounts, no network calls (even Mermaid diagrams render locally in pure Rust).
However, files are stored as plain text, same as Obsidian/VS Code/any text editor. Encryption at rest isn't currently on the roadmap.
For encrypted storage, you might consider: - Using Ferrite with an encrypted volume (VeraCrypt, LUKS, FileVault) - git-crypt for encrypted git repos
That said, if there's strong interest in built-in encryption (vault-style or file-level), I'd love to hear more about the use case. Would you want password-protected vaults? Per-file encryption? Something else?
I want cold storage encryption which is cross-platform and doesn't require FUSE and such. Current solutions are all either non-cross-platform or overkill, so I'm still using Obsidian non-encrypted. It's a matter of default and ease of use.
That said, I've checked Ferrite out – unfortunately there's a very long way to go before it becomes Obsidian-ish (left and right panel, add tabs, hide the top formatting bar), better focus on those features. If it becomes close enough – I'll implement the encryption myself :)
Fair feedback! You're right — Ferrite isn't Obsidian-complete. Those are reasonable additions: - Left panel already exists (file tree + outline), but could use polish
- Right panel (backlinks?) would come with v0.3.0 wikilinks work
- Hiding toolbar is a quick settings addition — I'll add that to the list
What's your priority order for those? And if you do implement encryption later, I'd love to see the approach!
Main priority would be the editor itself to be similar to Obsidian (with links etc.) but maybe better, Obsidian is annoying for example when you edit a TODO list (which is 99% of the time for me), go to the beginning of the line, then press down to go to the next item -- Obsidian jumps into position between "- [ ] " and "item text", instead of staying at line beginning. Long story short, many small details to make this right.
The TODO list cursor behavior is exactly the kind of polish detail that matters. I'll add this to the issue tracker — cursor should respect line start position, not jump past the checkbox syntax.
These "many small details" are what v0.3.0's custom editor widget will unlock. egui's TextEdit doesn't give us fine-grained cursor control, but replacing it will.
I don't know much about the GUI space. I would love your take on why did you went with egui instead of guirs
Good question! A few reasons for egui over gtk-rs/iced/others:
- Immediate mode — egui redraws every frame, which makes state management simpler (no callback hell). Great for prototyping.
- Pure Rust, minimal deps — egui is self-contained. gtk-rs requires GTK installed on the system.
- Cross-platform out of the box — Same code runs on Windows/Linux/macOS/Web
- Rapid iteration — Hot reload-friendly, easy to experiment with layouts
Trade-offs: egui's TextEdit isn't designed for code editors (no multi-cursor, can't hide folded text), which is why v0.3.0 will replace it with a custom widget.
Made the fan in my Windows 11 laptop spin up.
This is why I prefer clunky hardware with heating cpus and a slow disk. You can easily feel that you wrote bad code from audio and tactile feedback.
I’ve heard of people doing ambient performance profiling by instrumenting their code to insert clicks into an audio buffer based on a high precision clock and piping it out a speaker. You get to learn the sound of your code at 44.1KHz
This might be the most absurdly terrific thing I’ve read in a while - like a profiler equivalent of a Geiger counter.
We did something like that for a hiring project once:
https://github.com/tonarino/acoustic_profiler
*vibe coding sounds* "3.6 roentgen. not great, not terrible"
Which view/file caused this? v0.2.2 (coming soon) has significant performance optimizations for large files - deferred syntax highlighting, galley caching. If you can reproduce, please open an issue with details!
I launched the file, typed:
>Now is the time for all good men to come to the aid of their party. >test
and selected the last and made it bold using the formatting bar.
Thanks for the repro steps! This is helpful, formatting bar interaction shouldn't spin up the fan for such a small document. v0.2.2 has some performance improvements and is out, so it might be better, but this specific case might need investigation.
v0.2.2 just released — addressing several issues raised in this thread:
- CJK font support 1 — Korean/Chinese/Japanese characters now render properly
- CLI improvements (#9, #10) — ferrite file.md now works, plus --version and --help flags
- Undo/redo fixes 2 — Fixed scroll reset and focus issues
- Default view mode setting 3 — Can now set split/preview as default
- Configurable log level 4 — Reduce stderr noise
- Ubuntu 22.04 compatibility 5 — .deb now works on 22.04+
Thanks to everyone who reported issues! Download: https://github.com/OlaProeis/Ferrite/releases/tag/v0.2.2
Wish there was something like Mermaid for typical AWS Architecture diagrams.
Something that doesn't suck like draw.io!
Interesting use case! Mermaid doesn't have native AWS icons, but for v0.3.0's standalone crate, we could potentially support custom shapes/icons. D2 has better icon support if you need that now.
What specific diagram types do you need — network topology, service flows, infrastructure layout?
The main issue is that Markdown remains a pretty primitive language to write documents in, with dozens of incompatible extensions all over the place.
I don't know if it's the best format to focus on.
Fair point about fragmentation! Ferrite uses Comrak which implements CommonMark + GitHub Flavored Markdown (GFM) — arguably the closest thing to a "standard" we have.
We chose Markdown because: - It's what most developers already use (README files, documentation, wikis) - Plain text files are portable, grep-able, git-friendly, and won't lock you in - GFM covers tables, task lists, strikethrough, and autolinks which handles 90% of use cases
We also support JSON, YAML, and TOML with native tree viewers. Wikilinks ([[links]]) and backlinks are planned for v0.3.0 for folks wanting Obsidian-style knowledge bases.
That said, I'd love to hear what format you'd prefer — always interested in expanding support!
asciidoc or rst/sphinx, are tools which are much better suited to build software documentation with cross-references etc.
AsciiDoc and RST/Sphinx are definitely more powerful for structured documentation with cross-references, includes, and admonitions.
For now Ferrite is focused on Markdown since that's the most common format for notes and quick docs. But the architecture could support other formats — the parser layer is modular.
If there's demand, AsciiDoc would be the easier addition (cleaner syntax than RST). Would be curious how many folks would use it as their primary format vs. Markdown.
This is one reason why I created TapirMD, which offers better specificity.
Very cool. The one thing that prevents me from trying this out as a potential note-taking daily driver is the lack of support for LaTeX.
I recently switched from Obsidian to Zettlr due to some rendering and performance issues on Linux, and it's been a great experience. However, I always like to see new entrants in the arena.
LaTeX support is a reasonable request! It's not on the immediate roadmap, but here's my thinking:
Options considered: - KaTeX/MathJax-style rendering (would need a Rust math renderer or JS bridge) - Typst integration (Rust-native, modern alternative to LaTeX) - External tool pipeline (render via pandoc/LaTeX CLI)
Typst is interesting since it's also Rust-based and simpler than full LaTeX. Would inline math ($x^2$) and display math ($$...$$) cover your use case, or do you need full document features?
Added to the roadmap consideration list. Thanks for the feedback!
I only need inline+display math, I don't need the full document features.
Good to know! Inline + display math is a more tractable scope. Typst or a Rust KaTeX port could handle that without needing full LaTeX. Added to the consideration list with that clarification.
Markdown and Mermaid support, you have my attention!
Slightly off topic: is there any editor (and data format) that supports re-arranging mermaid charts? I often find myself wanting to slightly tweak the way the chart is rendered, e.g. moving around boxes so that some of them are clustered in a specific area etc.
Currently Mermaid doesn't support manual positioning — the layout is algorithmic (Sugiyama-style for flowcharts). Some workarounds: - Use subgraph blocks to cluster related nodes - Adjust edge order in source to influence layout - D2 (another diagram language) has better manual positioning
For v0.3.0's standalone crate, I'm considering whether to expose layout hints. What specific use case do you have — documentation, architecture diagrams?
Made with egui, if anyones wondering.
I love the new era of graphical applications in Rust.
Looks interesting! I’m discouraged from using mermaid and D2’s online playground for privacy reasons and have hand on my roadmap to get a local editor. This might be it! Does it support theming of mermaid diagrams, I noted the style keywords were in the roadmap still.
Great catch! Mermaid styling syntax (style and classDef directives) is on the roadmap for v0.3.0. Currently the diagrams render with Ferrite's theme colors (light/dark).
For privacy, you're in the right place — Ferrite's Mermaid rendering is 100% native Rust, no JavaScript, no external services, no network calls. All ~6000 lines of diagram rendering happen locally. We're even planning to extract this as a standalone crate so others can use it.
It’s a cool name but there is already another project called ferrite, related to audio recording. https://www.wooji-juice.com/products/ferrite/
Thanks for flagging this! You're right — Wooji-Juice's Ferrite is a well-known iOS audio recording app.
The name collision is unfortunate. We picked "Ferrite" for the magnetic/persistent storage connotation (ferrite cores were early computer memory). Different domain (text editor vs audio), different platforms (desktop vs iOS), but I understand the SEO/discoverability concern.
Open to suggestions if the community feels strongly about a rename! Though at this stage, with GitHub issues, releases, and now HN discussion, there's some established presence.
Any interest in a plugin system similar to Obsidian?
Definitely interested in the concept! Though it's not on the immediate roadmap.
A few thoughts: - Obsidian's plugin system is JavaScript-based, which makes sense for Electron. For a native Rust app, we'd likely want something like WASM plugins or Lua scripting. - v0.3.0 includes plans to extract the Mermaid renderer as a standalone crate and potentially the editor widget as a library — this modular architecture would be a foundation for future extensibility.
What kinds of plugins would you want? Knowing specific use cases would help prioritize. Custom renderers? File format converters? External tool integrations?
In the meantime, Ferrite has a "Live Pipeline" feature that lets you pipe JSON/YAML through shell commands (jq, yq, etc.) — not a full plugin system, but useful for custom transformations.
Doesn't install on Ubuntu 22.04 LTS due to dependecy problems. Filed a bug: https://github.com/OlaProeis/Ferrite/issues/6
Thanks for reporting! This is a build environment issue - v0.2.1 was built on Ubuntu 24.04 which has newer glibc (2.39) and libssl3t64.
*Fix:* I've updated the CI to build on Ubuntu 22.04, which will make the .deb compatible with 22.04+.
This will be included in v0.2.2. For now, workarounds: 1. Use the `ferrite-linux-x64.tar.gz` (standalone binary) instead of .deb 2. Build from source: `cargo build --release`
Sorry for the inconvenience!
Hey OP, curious how much experience you have with Rust, given that this is the only rust repo I see in your profile.
This is my only public Rust repo — I have some ongoing private projects in Rust, so I'm familiar with the ecosystem (cargo, crates, the borrow checker experience, etc.).
That said, to be fully transparent: as I disclosed elsewhere in this thread, the Ferrite codebase is 100% AI-generated (Claude via Cursor). I direct the development, test, and iterate, but I haven't written the Rust by hand for this project.
So my Rust experience is more "ecosystem familiarity + reading AI-generated code" than "battle-hardened Rustacean." This project is partly a learning exercise — seeing how far AI-assisted development can go while picking up Rust patterns along the way.
seems like a promising alternative to obsidian, but missing [[wikilinks]] and back references
Not yet! [[wikilinks]] and backlinks are natural additions. I will add it to the Roadmap? Love community input on what Obsidian features matter most!
Yes! I was looking at it and hoping they had that feature already. I so want an Obsidian alternative to exist just in case.
Thanks for posting the GitHub issue!
Building an api client based on markdown as well - https://voiden.md
And what's the connection with the thread?
Whats the advantage of using Ferrite versus VS Code with a Mermaid extension?
> - ~15MB vs ~300MB+ (no Electron) > - Instant startup vs seconds > - Native Mermaid rendering (no extension juggling) > - Built-in JSON/YAML tree viewer with pipeline shell integration > - Session restore, minimap, zen mode baked in > > If you live in VS Code already, an extension might be fine. Ferrite is for those wanting a focused, fast Markdown environment.
Rust + Native App I take it
The VSCode markdown viewer kind of sucks tbh.
For those who, like me, read this and thought "what the hell is a mermaid diagram?", apparently it is a method to describe simple flow diagrams using markdown-like text. More here: https://mermaid.js.org/
Next time you're vibe coding something, have the system generate a mermaid diagram to show its understanding. Though visual generation can be hard for models, structure/topology in formats like mermaid is pretty gettable.
I've even found sonnet and opus to be quite capable of generating json describing nodes and edges. I had them generate directed acyclic processing graphs for a GUI LLM data flow editor that I built (also with Claude - https://nodecul.es/ if curious)
Consider adding support for Typst.
Interesting idea! Typst is compelling (Rust-based too). Not on immediate roadmap but could be a future addition. TeX is heavier but possible via external tools + pipeline feature.
Or even better, TeX. I realize capital bought out even basic typesetting but let's not encourage this
Typst is open-source.
Open source doesn't mean relinquished from capital by any means. I also don't blame the author of typst. But TeX is truly free from capital, and that should mean far more than the aesthetics of a nicer interface.
Integration with typst will be more straightforward than latex.
Yes, at the cost of dragging people into subscription software. Fuck off
Is mermaid rendering implemented in Rust, or are you running mermaid.js in a JS interpreter somewhere?
On other systems I’ve run into challenges rendering markdown documents with many mermaid diagrams in them. It would be nice to have a more robust way to do this.
Looks like it’s currently a subset of mermaid natively in rust https://github.com/OlaProeis/Ferrite/blob/master/src/markdow...
(not associated, just looked at the code - no js interpreter)
https://github.com/OlaProeis/Ferrite/blob/master/src/markdow...
100% pure Rust! No JS interpreter. Parses Mermaid syntax directly and renders via egui drawing primitives. Supports 11 diagram types: flowchart, sequence, state, class, ER, pie, mindmap, timeline, user journey, git graph, gantt. Much faster than spawning headless Chrome!
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