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Show HN: Node.js video tutorials where you can edit and run the code

258 points by somebee ↗ HN
Hey HN,

I'm Sindre, CTO of Scrimba (YC S20). We originally launched Scrimba to make video learning more interactive for aspiring frontend developers. So instead of passively watching videos, you can jump in an experiment with the code directly inside the video player. Since launch, almost two million people have used Scrimba to grow their skills.

However, one limitation is that we've only supported frontend code, as our interactive videos run in the browser, whereas most of our learners want to go fullstack—building APIs, handling auth, working with databases, and so forth.

To fix this, we spent the last 6 months integrating StackBlitz WebContainers into Scrimba. This enables a full Node.js environment—including a terminal, shell, npm access, and a virtual file system—directly inside our video player. Everything runs in the browser.

Here is a 2-minute recorded demo: https://scrimba.com/s08dpq3nom

If you want to see more, feel free to enroll into any of the seven fullstack courses we've launched so far, on subject like Node, Next, Express, SQL, Vite, and more. We've opened them up for Hacker News today so that you don't even need to create an account to watch the content:

https://scrimba.com/fullstack

Other notable highlights about our "IDE videos":

- Based on events (code edits, cursor moves, etc) instead of pixels

- Roughly 100x smaller than traditional videos

- Recording is simple: just talk while you code

- Can be embedded in blogs, docs, or courses, like MDN does here: https://developer.mozilla.org/en-US/curriculum/core/css-fund...

- Entirely built in Imba, a language I created myself: https://news.ycombinator.com/item?id=28207662

We think this format could be useful for open-source maintainers and API-focused teams looking to create interactive docs or walkthroughs. Our videos are already embedded by MDN, LangChain, and Coursera.

If you maintain a library or SDK and want an interactive video about it, let us know—happy to record one for free that you can use however you like.

Would love to answer any questions or hear people's feedback!

94 comments

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revskill
Awesome. But only JS is supported ?
somebee
Right now, only js is supported out of the box, but I guess any language that can run via web assembly or other techniques could work. WebContainers has experimental python support, but it won't work with a lot of the dependencies you would usually utilize in python etc.
ach9l
we should be able to use this as a vscode extension to solve this issue. is there an sdk to integrate this into electron apps?
somebee
We are finalizing an electron app as we speak. That will allow recording anything that runs on your own system
huksley
Supercool! Can you use any other webapp, not a code IDE?
mrborgen
Thanks! Not sure I fully understand — do you mean using our DOM recorder on other web apps instead of our IDE? In theory, yes, we’ve used it on third-party sites in previous iterations of Scrimba.

But there are some limitations, as certain HTML elements (like native dropdowns, date pickers, canvas etc) are rendered outside the DOM and thus can’t be recorded.

kamikazeturtles
Scrimba is really cool. When I first got into programming, a few years ago, I tried to build something similar using rrweb but with server side code execution in docker containers so that it could support all the programming languages like replit.

When I first heard about Scrimba, I abandoned my project because I thought you guys would already go down that path. Why didn't you guys go down that route?

mrborgen
Good question! Expanding from client-side JS to Node.js is our first step in that direction. We considered server-side execution for all languages but chose WebContainers instead, as it’s a better fit for us when teaching fullstack web dev, and easier to maintain.

That said, our new IDE is built to easily support server-side execution down the line.

remisharrock
Actually I have a new version of codecast doing that ! (See my post a minutes back in that thread)
ForOldHack
It has the possibility of being really really cool, but after using it for a 5 day tutorial:

1. There is a cross dependence on the mail server: I used live.com to log in, and was stuck running in edge. I then tried my google account, and was stuck running in chrome, If I used my yahoo account, I could run in any browser. A good idea would be to mail a cookie... and then we could choose any browser, and while this was all happening, Nightly/Firefox took a major dump in many of my systems. So... I used chrome.

2. I would like to be able to mirror the code window in my favorite one of the top 3 editors: so... either I could choose a font in your system, or I have to get my other editor to use YOUR font, your spacing, your beautifier, and your color scheme. I opened three bugs in VS Code, one in a plug-in ( yes, prettier is absolute garbage, I may make a cb(1) plugin. ). I opened a bug in Sublime... Also I opened a bug in Notepad ++.

I am now forcing myself to relearn Lisp for emacs. Its really quite brilliant. I would wonder if it would all be possible to implement this all into emacs.

FYI: When I am taking jobs freelance I ask them 3 questions: 1. What is your tool chain? 2. What editor are most of your engineers using? 3. What is the best font for programming?

I have not used Roboto, but now am forced to do it. My favorite font is Arial Narrow, mono-spaced.

As for the highlighting colors, How hard would be a preferences export for VS Code/Zed/Notepad++/emacs to match your color screen so... ( paper balls loaded and ready )...

"What you code is what you get."

And lastly... why is WSL2 so broken? and why is syncing between containers so evilly difficult. The Alpine community has been a great help.

ahmadrosid
Amazing, this is much more better than learning with AI.
hliyan
Minor issue, Chrome on Windows: cursor position seems to have an offset error -- can never quite get to the end of a line. As you type, text doesn't quite appear where the cursor is.
somebee
Will try to push a fix in the next few hours. We are instantiating the monaco editor with a custom font (Source Code Pro) before we're sure the font has loaded, which throws of the char box measurements in monaco. We did have a fix for this in the old (non-backend IDE), so I'll port that over ASAP. Thanks for notifying us :)
benslv
I taught myself React using the Scrim a platform, so I feel very supportive and thankful to you for building it. Being able to directly interact with the code being shown onscreen was invaluable to me for understanding it.
porsager
Imba is probably one of the best kept web development secrets! Sindre has done a remarkable job of making an insanely terse while powerfull language for building web applications. Not that it's limited to web applications only, the syntax translates perfectly for any other area as well.

The fact that a platform like Scrimba was built using this language and probably only a handfull developers should make you want to learn from someone like that even more!

It's also the only learning platform I've ever recommended where I see people staying and learning more.

pier25
I'm hoping Imba will get more attention with the upcoming v2 release. It has tons of cool ideas and the "no reactivity" state paradigm is so much easier to reason about.

Also its css notation is what Tailwind should have been.

Btw you're the Postgres.js author, right?

porsager
It's got all the right decision for the scope it's covering!

Yeah, I'm the author of Postgres.js, although it hasn't gotten the tlc it deserved lately cause I've been too busy with another soon to be public project.

barrenko
Not sure of how much help is it to OP, but I'd also like to commend Imba's front page paint demo, it's just so neat.
evnp
It's beautiful, but note to OP it doesn't work great on Android Chrome for me - can only draw very very short lines.
flanbiscuit
Something seems to be broken in the Imba website for me in both FF and Chrome for MacOS.

When I go to the main website: https://imba.io/

Then click on the "Demo" button

I get taken to the "Playground": https://imba.io/try/examples/apps/playground/app.imba

There is no code on the page but the preview seems to work. Same thing with all of the other examples. They work in the Preview panel, but no code loads at all.

Looking in the dev console I see a few errors:

   GET https://imba.io/monaco/min/vs/loader.js HTTP/1.1 404 Not Found

   Uncaught ReferenceError: require is not defined
  
   current file did set undefined
Some images and a preflight.css is also not found
ushakov
fun fact I learned about Imba is that it's name stands for "imbalance" (like in computer games!)
zersiax
I love this idea, it would actually solve a lot of accessibility issues within coding courses for the fully blind. Unfortunately right now the scrimba interface appears to need some help where that is concerned. WOuld love to discuss more if you're interested? @somebee
seansh
This looks fantastic! I’ve been seeing a growing number of tools trying to bring more interactivity to programming tutorials and for good reason. Screencasts are too passive, and it’s easy to get lost halfway through. Books and blogs don’t really show how code evolves over time either.

I’m working on a solution too, called CodeMic [1] where instead of bringing the environment to the web, it brings video and workspace sync into the IDE so viewers can follow along directly inside their own editor.

You’ve done an impressive job integrating everything, including the Console for example, that’s especially tricky to pull off in an extension for VSCode, Emacs, or Vim.

[1] https://CodeMic.io

mrborgen
CodeMic looks very cool, well done! A lot of people have asked us over the years whether we they can implement Scrimba into their preferred IDE, so it makes total sense to take that approach as well.
jasonjmcghee
Interactivity and liveness in programming deserves to be discussed far more often than it is on front-page of hacker news, but excited there are multiple ongoing threads!

I'm a very strong supporter of interactive blogposts as well. Obviously https://ciechanow.ski/ is leader here - being able to mess with something to build intuition is huge.

seansh
Agreed. ciechanow.ski has been a huge inspiration, as well as 3blue1brown, Bret Victor, and Chris Granger (remember Light Table?). But none of them provide a way to walk through thousands of lines of real code and show how it is built and evolves over time. That is the key problem Scrimba and CodeMic are trying to solve.

The two people I have seen who really master this are Robert Nystrom (Crafting Interpreters) and Casey Muratori (Handmade Hero). But even they are limited by the mediums they use: books and videos, which are not ideal for this kind of guided exploration.

hairama
At the end of 2023 Sony & Steam informed me that I spent hundreds of hours playing games.

“Hundreds of hours?!? With that much time I could learn to play the piano or speak Spanish! Hell, I could learn to code!”

I stumbled across Scrimba on a Reddit thread and signed up for the paid version after a few lessons: it was unlike anything I had tried in the past.

Now I’m able to build basic react apps but I have a much better understanding of what’s going on “under the hood”.

Have you thought about using it to introduce new hires to a codebase?

mrborgen
Very glad to hear that! Yes, we’re working on a desktop app (currently in alpha) that lets you record Scrimba screencasts of local codebases. It’ll be perfect for onboarding, and since it runs on your own machine, it can support any language.
sylens
Would love to see a blog post about your journey if you wrote one (or are planning to). Other resources used, key lessons along the way, etc. Scrimba looks great but surely there has to be a point where you take off the training wheels, right?
nailer
I don’t understand. If the audience member makes a change, and then the speakers events are played back on top of the change, the code won’t make sense.
mrborgen
If you make a change, then the screencast pauses and you create a branch of the codebase, so that you can experiment on your own.

Once you hit "play" again, your changes are reverted and you continue watching the teacher's code.

So the teacher's voice is never on top of your code, as that wouldn't make sense.

seveibar
Would love to use this for interactive tscircuit tutorials! Is it easy to create a course? The output looks great!

Is the web preview saved as a video or rendered dynamically? In the case of tscircuit, we run an autorouter in the background so it can be like a slow-loading website with a big project- I imagine doing courses on building games would have a similar problem if there isn’t video capture for the preview.

mrborgen
Would love to see tscircuit tutorials on Scrimba! It’s easy to record — just talk over the code. I demo it in this scrim from around 1:40. https://scrimba.com/s0kmcarts1

The preview is rendered live, not video. So with heavy projects (e.g. lots of JS animations), the recording can get large due to the detailed DOM stream.

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kirykl
Scrimba is such a great learning tool, I’ve tried the front end material, excited to check out the new stuff
barrenko
This looks to be the perfect usecase to throw an agent into the loop (sorry for saying so).
ach9l
yep, this is not for humans, agents with dia-1.6B or anything similar, they will outclass humans at this, really quick. i'd like to work on a poc if you are interested, i train and deploy models for a living.
nozzlegear
What do you mean it's not for humans, and that agents will outclass humans at this? Humans like to learn new things, and this seems like a novel format for learning. I don't think an AI is ever going to "outclass" our curiosity or desire to learn.
ach9l
oh, i meant humans as teachers. if i had to choose between a human teaching me quantum physics equations or a collection of richard feynman’s lessons turned into agentic lessons, i’d pick the agent. i mean, we can compile the whole collection of lessons in agentic form way faster than any human could deliver the same number of lessons.

the product is exclusively for humans. the teacher, i'm not so sure.

nozzlegear
That makes a lot of sense, thanks for explaining.
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giancarlostoro
CodeSchool used to be interactive until PluralSight bought them out, then pulled in all the videos, but kept none of the interactivity. Shame.

There's also the Processing tutorial series which is insanely interactive:

https://hello.processing.org/

Sharing these in the hopes they server as inspiration for anyone who works on educational programming content.

rglover
This is wild. I'd love to use this to do a demo app for my JS framework, Joystick [1]. Would a collab be possible (happy to contribute the end result to the Scrimba library)?

[1] https://cheatcode.co/joystick

mrborgen
Yes, we'd be happy to collaborate on creating something on Joystick. It looks like an awesome framework!
rglover
Awesome, thank you! What's a good way to get in touch?
mrborgen
Just send me an email at per@scrimba.com :)