The knowledge required to build production grade authentication, handle Stripe webhooks, or design a rate limited API has been free and publicly accessible for a decade.
Engineers making $200k aren't hoarding secret information. They have reps. They've built these systems under pressure, with specs, with tests that tell them when they're wrong.
That's the gap, it's not knowledge. Reps under realistic conditions.
The way we practice is broken
Think about how most developers "practice" right now:
Algorithm platforms: You solve puzzles in a blank text box. No file system, no terminal, no dependencies. Then you wonder why you freeze when someone asks you to build something real.
Tutorial projects: You follow along, copy the code, it works. You feel productive. Two weeks later you couldn't recreate it from scratch if someone paid you.
Side projects: You build what you want, skip what's hard, never get feedback on whether your approach was actually good.
None of these simulate what the job actually is: you get a spec, you open a codebase, you figure it out, and someone reviews your work.
What "reps" actually looks like
When I thought about what actually leveled me up as a developer, it was never solving algorithm puzzles. It was:
- The first time I wired up JWT auth with refresh tokens and realized I had no idea how token rotation worked
- Struggling through my first Stripe integration and learning why webhook idempotency matters the hard way
- Building an API and finding out my "working" pagination broke on edge cases because I never tested past page 1
These are the reps that compound. And there was nowhere to practice them deliberately.
So I built one
I spent 8 months building RealDev, a platform where you practice building real features, not solving puzzles.
Here's what a session looks like:
- You pick a challenge (e.g., "Build a JWT authentication system" or "Add rate limiting to a REST API")
- You get dropped into a real development environment, full terminal, package manager, actual dependencies
- You write real code across real files
- Your submission runs against integration tests that check actual behavior, not "does this function return 42"
- AI-powered code review tells you what a senior dev would flag in PR review
The challenges are the stuff you'd actually do at work: auth systems, CRUD APIs with validation, payment flows, real-time features.
The hardest part of building this
Running isolated code execution was brutal. Each user gets their own Docker container with a full dev environment: Node.js, Python, Go, Java, C, real package managers.
I also massively underestimated challenge design. Writing a good real world challenge is 10x harder than writing an algorithm problem. You need realistic specs, integration tests that check behavior without being brittle, and a difficulty curve that teaches without handholding. I threw out more challenges than I shipped.
What this is NOT
Being honest:
- Not a replacement for learning fundamentals. If you don't know what an API is, start with tutorials first. RealDev is for people who know the concepts but need reps.
- Not going to help you pass FAANG algorithm rounds. If your target company asks you to implement Dijkstra's, go grind LeetCode. I'm not pretending that's going away.
- Not a massive platform yet. I'm a solo dev. The challenge library is growing but it's not hundreds of challenges deep. Quality over quantity for now, starting simple.
Try it, roast it
It's live at realdev.dev with a free and pro tier. I'm building this in the open and genuinely want feedback. What challenges would you want to see? What's missing? What sucks?
The thing I keep coming back to: every senior dev I know got good by building real things under real constraints. Not by solving puzzles. I just want to make those reps more accessible.
What's the skill that actually leveled you up as a developer? I'd bet it wasn't an algorithm.
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