Solo-built a "learn by doing" coding app because tutorials never actually made me code
I've spent the better part of the last year building this on nights and weekends, so this is my first real post about it.
The itch: every time I tried to learn something new (a language, SQL, whatever), I'd watch a course, nod along, and then... not be able to do any of it. Passive formats don't stick. And the AI tools that popped up were worse: they'd tell me "great job" no matter what I typed, so I never actually knew if I understood anything.
So I built Tully. You describe what you want to learn, it generates a hands-on lesson, and instead of watching, you do the work: write real code, build a diagram, explain the idea in your own words. Then it grades what you actually produced and adapts the next step to how you did.
The part I care most about (and the part that was hardest): the grading is honest and server-authoritative. Your code runs server-side in an isolated sandbox and it's graded on what the code actually does, not string-matching, and the answer key never reaches the browser so you can't game it. No "great job" unless you earned it. That's the whole thesis: you learn by doing, and honest feedback is what makes it stick.
Where I'm at: early, and the thing I'm genuinely unsure about is whether the first lesson feels worth someone's time and whether people trust the feedback. So I'd love a brutal look. You can run a full graded lesson without signing up: https://tullycourses.com/for/developers
What I'm hoping to learn from you: does the core loop land in the first two minutes, and where does it feel like just another ChatGPT wrapper? Solo founder, I read everything.
Hey! Congrats on Tully Courses — the "write real code, get it executed and graded instantly" angle is genuinely differentiated from quiz-heavy platforms.
I've been using Zarek (an AI launch partner built for SaaS founders) to handle the launch roadmap for a similar developer tool, and it put together something I'd never have done manually. Here's roughly what it built for Tully in minutes:
What Zarek generated for a product like Tully:
Positioning copy — e.g. "Unlike chatbots that answer questions, Tully tests you with live code execution and builds an adaptive skill map based on your actual performance." Channel-specific, not one-size-fits-all.
Channel plan — prioritized Reddit (r/learnprogramming, r/webdev), Hacker News Show HN, dev newsletters (TLDR, Cooper Press), and Product Hunt — each with timing, post format, and a draft.
SEO blog post outline — e.g. "Why code challenges beat tutorials for learning JavaScript" → targets long-tail dev learners searching for practice platforms.
Demo video brief — script structure: show the sandbox, submit code, see the grade + skill map update. 60-second hook for Twitter/X.
Launch day sequence — staggered posts so HN, Reddit, and PH don't cannibalize each other.
All of it is revisable, channel-aware, and stored in a living plan that updates as you learn what's working.
If you want to see the actual copy Zarek drafted for a dev-tool launch, happy to share more. You can also just try it yourself: https://zarek.tech/
Or reach out directly: wangc2016217@gmail.com
Hey, really cool product — the idea of generating hands-on coding lessons from a goal or deadline is something I've wanted for ages.
I'm building [Zarek](https://zarek.tech/) — an AI launch co-pilot for SaaS founders. Thought you might find it useful, so I ran Tully Courses through it to show what it actually produces.
Here's what Zarek put together for a launch like yours:
Channel plan — it mapped out the right venues (Hacker News, Product Hunt, dev-focused newsletters, SEO blog) and scheduled each one in sequence, rather than blasting everything at once.
> Example step: "Submit a Show HN post on Tuesday 9am PT — lead with the 30-second demo, not the feature list. Title: 'Show HN: I built a tool that generates runnable coding lessons from your goal or deadline.'"
Copy per channel — it drafted distinct copy for each venue, not one post copy-pasted everywhere.
> Example (Reddit r/learnprogramming): "I kept hitting the same wall — tutorials that teach syntax but don't make you write anything real. So I built Tully: paste in your goal ('learn async/await in 3 days'), it builds a lesson, you write real code in the browser, it runs and grades it. Would love brutal feedback."
SEO blog draft — it outlined and wrote a first draft targeting the specific search terms your audience uses.
> Example title: "How to Learn a New Framework in 72 Hours (With Real Code, Not Toy Examples)"
The whole thing took a few minutes. You review, approve, or edit each piece before anything goes anywhere — nothing auto-posts to your accounts.
If you want to try it: https://zarek.tech/
Happy to answer questions too — wangc2016217@gmail.com
The distinction between generating an answer and evaluating what someone actually produced is pretty clear here. I’m curious which part users notice first when they try the lesson.