Replit Blog

It's CodeMirror! All I had to do was write a Janet grammar for it -- very easy to do. CodeMirror is pretty amazing -- I was able to implement the "edit values with your mouse" by just asking CodeMirror for the syntax node under the cursor, checking if it parsed as a number, and if so replacing it with a different string. https://codemirror.net/ https://github.com/ianthehenry/codemirror-lang-janet I went with CodeMirror after reading this post: https://blog.replit.com/codemirror and I've been super happy with it.

Yes, most things on Replit are open-source. Just click "show files" on the top-left corner. Also it's powered by Nix, and we wrote a ton about it here: https://blog.replit.com/

Great article. Im still super hurting that we have great cloud ides but no collaborative/multiplayer experiences except closed/proprietary ones. There's beena number of attempts in Theia or Che, but nothing has panned out to my knowlege. As for closed/proprietary cloud envs, there's good options: Microsoft has LiveShare which works great. Repl.it just had a really fun write up on their multiplayer debugging but again a closed product: https://blog.replit.com/multiplayer-debugging

Patrick from Replit here. Excuse the self-promotion, but if you're curious how Fig got started by building their MVP on Replit, check out their interview on our blog: https://blog.replit.com/fig. Edit: And of course big congrats to Matt and Brendan on the launch! It's been a lot of work and a long time coming. You've built a great product!

If you want a fuller explanation, I'll just ramble about some random bits. Replit will let you create an account, with which you can create "repls": on their own, they are the "disk images" I mentioned; they store files and a few other bits on Replit's servers. You can open this repl if you own it, and edit it in the in-browser (Monaco-based) IDE. Because you own it, Replit will spin up a VM on its servers to handle your session. Your changes sync in real-time with the permanent files in the repl, as well as the live (and ephemeral) filesystem of the VM. All of this happens over the WebSocket-based protocol I mentioned. What you're seeing with this post's link is a repl owned by someone else; in such a case, you see the "Spotlight View", which is read-only. You can fork it to create your own copy of the repl, which you can edit. The list of files is a read-only view of the repl's files. When you run it, it'll spin up a VM similarly to how it does for you with the IDE. The VM I've been mentioning is a restricted Docker container running on some GCP container instances, managed by Replit. It runs Ubuntu 20.04 LTS (I think) if that's what you want to know. The desktop you see when you run this post's link is a VNC connection to a Fluxbox desktop on the VM. The console is sent from the VM to your browser (again, all of this is over that WebSocket protocol) and rendered by xterm.js. Overall it's a bit of a messy system, and there's quite a few other things not mentioned; they'll…

Also Replit raises $400 million at a $9 billion valuation https://blog.replit.com/replit-raises-400-million-dollars

I've used Replit for educational materials when teaching beginners Python and JavaScript. They had a nice product called Teams for Education. It was even announced that it'll become fully free (the original blog post with the announcement was deleted from their website) [0], but soon after that the company had pivoted to AI and later discontinued the Teams for Education completely [1]. I also used Replit's embedded widgets for occasional lessons, but they kept changing the UI and behavior, making it difficult to write consistent reliable documentation for beginners. I think by now it's clear that the product is not meant for educators, like it was originally, so that's ok. [0]: https://web.archive.org/web/20240924020257/https://blog.replit.com/tea… [1]: https://blog.replit.com/update-on-teams-for-education

Replit | Full-Time Engineering Roles | Hybrid in Foster City, CA Build software faster. Replit is an AI-powered software development and deployment platform for building, sharing, and shipping software fast. Look what we've been up to: https://blog.replit.com/introducing-replit-agent Available Roles: - Software Engineer, Platform - Software Engineer, Workspace UX - Software Engineer, Product - Staff Software Engineer, Product If you're interested in something else, join our Talent Network Apply here: https://jobs.ashbyhq.com/replit?utm_source=HackerNews

It's also used at Repl.it: "How we went from supporting 50 languages to all of them" https://blog.replit.com/nix

We actually announced that Ghostwriter is now free for all users last week: https://blog.replit.com/ai4all. The free tier is using a smaller model for chat than the paid version for cost reasons, but it has all the same integrations (inline suggestions/code transformation/etc). (Disclaimer, I work at Replit on the AI team, but don't represent the company)

Disclaimer: I work at Replit. You can read all about our hosting changes here: https://blog.replit.com/hosting-changes. TL;DR - deprecating always on in favor of new deployments product - migrate workspace URL to replit.dev from repl.co - replit.dev is the new development URL. only available when someone is in the editor. - deployments are the only way to host things on replit From the blog: > We remain committed to providing a powerful free development experience to anyone who wants to code. This post is only about the hosting experience, which we are migrating to our new Deployments product.

This is the blog post where the "20 million developers" quote came from: https://blog.replit.com/20-million-developers Those 20 million, what are they? Created user accounts? Active user accounts? User accounts that created at least one Repl? I have at least three Replit accounts - one on my uni email (which I no longer have access too), a previous work account (experimenting for doing interviews with it), and my personal account. Am I three developers? None of those accounts are active, do they count or not? If that 20 million figure is taken from anything less than active users I'd consider it deceptive. Which doesn't mean Replit the app is bad! But it does make the company a bit suspicious.

They trained on https://huggingface.co/datasets/bigcode/the-stack-dedup which is a massive curated dataset accumulated from GitHub. Details are here: https://www.bigcode-project.org/docs/about/the-stack/ Many of the most-represented "languages" on GitHub are actually things like JSON, XML, HTML, CSV, text, markdown, YAML, and SVG. More details from them here: https://blog.replit.com/llm-training

Replit seems to be all in on NixOS https://blog.replit.com/nix

I've done the same thing, first thing I tried with ChatGPT: https://imgur.com/a/d8LZicq Prompts: - Write a simple CRDT implementation in Swift - How can I make a GraphQL server using Rust using the async-graphql and actix-web libraries? - Write code to create a Dropbox clone in Rust - How do I make an HTTP request in Javascript? However, just like with Copilot, it can introduce subtle bugs. For example, in the Dropbox example, notice how it uses synchronous code in an async function. Also, longer prompts will reach the token limit and get cut off. Interestingly, this must be what Replit is also using for their AI codegen service too (https://replit.com/site/ghostwriter) since I believe they have some connection to OpenAI, as they got early access to OpenAI's service last year with their previous Codex product (https://blog.replit.com/codex).

> I feel it could become an easier Docker for people wanting to try programming with little fuss. In a lot of ways, repl.it is doing this. https://blog.replit.com/powered-by-nix

> I wonder if we'll ever really have something like that on top of Nix or NixOS. Xe, go do it! (: In all seriousness, Fly.io has explored this path (and very well may pursue it depending on RoI of going down this route, I'd imagine): https://github.com/superfly/recco Even though I'd like Fly.io to be more like Heroku, it is railway.app that comes the closest (but I believe they use buildpacks like Fly.io does rather than Nix/NixOS). Speaking of Nix, shout out to replit (https://blog.replit.com/nix) for having a holistic view of the product and it is unlike anything I've ever seen before. And unsurprisingly, most junior developers that I interact with, prefer replit over other alternatives. Heroku may be dead, but an entire range of upstarts have risen up in its wake: https://www.swyx.io/cloud-distros

Replit does this for their own services, and it seems like they might give you access to it, too[1]. That post is old and not very detailed, so maybe I'm misinterpreting it. 1. https://blog.replit.com/api-docs

I presume that is because it is a complicated feature, but not technically impossible? Although perhaps using contentEditable* makes an implementation more difficult? * From article: “CodeMirror would achieve that by leaning on native browser text editing (via contentEditable) rather than implementing text editing entirely in the library/javascript.”. Edit: from https://blog.replit.com/codemirror “CodeMirror 6 is a complete rewrite of the CodeMirror editor with a focus on accessibility, touchscreen support, and extensibility.”. I expect that marjin really cares about accessibility. However, in my limited experience, as a lone developer I couldn’t make our complex product properly accessible unless that was the focus of say six months effort, which we couldn’t afford at the time.

And there is also this more recent article https://blog.replit.com/codemirror of why they chose CodeMirror

FYI, this is a few months old, if you want to read something up to date, check out https://blog.replit.com/codemirror Unfortunately copy and paste doesn't work well on Firefox on Linux in any of these fancy editors because support for the primary selection is broken and Mozilla doesn't seem interested in fixing it: https://bugzilla.mozilla.org/show_bug.cgi?id=1593761 The article calls CodeMirror "lightweight" but the minified JS is still over 1 MB. If you want lightweight then you probably want something like CodeJar (https://github.com/antonmedv/codejar) which clocks in at 2 kB.

Replit actually has every nix package installed: https://blog.replit.com/nix They mount a 1TB volume with all packages preinstalled

(Replay engineer): Yes, replit has been working on adding similar functionality (https://blog.replit.com/debuggest). In fact: we've been collaborating with them on it! :)

I understand the feeling of being taken advantage of, but this seemed clearly like an over-reaction. A 100% apology was in order from my (sideline) opinion. He's just an ex intern having some fun, probably trying to impress his former boss even. I was reading through the replit blog to see what kind of things are trade secret vs public, and noticed that they didn't go out of their way to highlight that Bret Victor's "Learnable Programming" is clearly the complete inspiration for replit's debugger (time travel, no hidden state, etc). They have a small link to Bret's work but don't mention him by name. Considering Bret's article is basically THE piece to read w.r.t. programming environments, and the gif that replit shows looks pretty identical, it seems right to have his name/article clearly at the top. https://blog.replit.com/debuggest http://worrydream.com/LearnableProgramming/

Interesting take on ideas well presented in a blog post, dubbed as "CLUI": https://blog.replit.com/clui

> https://blog.replit.com/ventures > [...] Replit Ventures will give a grant of $2000 each [...] It's not a substantial amount money but a nice token of appreciation nontheless. I guess the real value comes in the form of networking, exposure and mentoring.

They are: https://blog.replit.com/betting-on-nix

My experience was seriously different. I started with Slackware, switched to Arch and after a failed attempt to run some AUR scripts, I was tired and switched to NixOS. Incidentally, I treat both my Emacs config and my NixOS and home-manager configurations as Igors. They are never really finished. In this sense, the "many months of effort to get to that point" does not matter. Also, with NixOS I feel I can be bolder than with other distros, knowing with way more accuracy what is breaking my configuration. > Yes, Docker is an ugly duck compared to Nix, but it brings 90% of the reproducibility benefits and probably everyone on your team can be up and running in hours. The Docker replit was using before Nix was going hopelessly "uglier": https://blog.replit.com/nix Also, what Cargo and NPM and `<insert lang here>` lockfile system do for each lang, Nix does in a more general package management level.

Author here. Glad to see the blogpost on HN! CodeMirror improved Replit's performance by a lot and by extension our retention. In fact, after releasing it to mobile in July[1] our weekly retention rate on mobile increased by a whopping 70%. That said, solve a lot of mobile usability issues so it's not all due to performance. On desktop however, it's a different story, we made sure to just have parity with Monaco and it still improved retention by %25, almost all due to performance! If you like working on performance come work at Replit, we want people that care about the performance of our systems! Adopting CodeMirror pushed us to write more in a more functional style that makes the code more fun and simple (not easy) in the shortrun, and more maintainable in the long run! My teammates write CodeMirror extensions for kicks and giggles, sometimes they end up releasing some "bret victor shit"[3]. If you like CodeMirror and end up using it in production, try to get your company to fund the project[4] and open-source as much as you can! [1]: https://blog.replit.com/codemirror-mobile [2]: https://blog.replit.com/codemirror [3]: https://blog.replit.com/kaboomdraw [4]: https://marijnhaverbeke.nl/fund/