Solve challenges sourced from real-world engineering at Google, Meta, Stripe, Spotify, Netflix, Shopify, Airbnb, Slack, Vercel, Nvidia, Uber, Atlassian, and Canva.

Everything you need to master AI coding

Real code

Production codebases from open source repos. Not toy problems or algorithm drills. You build features, fix bugs, and refactor in code that actually shipped.

AI built in

An AI copilot that sees your full context. Learn to prompt effectively, delegate the right tasks, and verify what comes back.

Get scored

Submit your code and see which tests pass and fail. Pro users unlock the full AI collaboration rubric with dimension breakdowns, badge tiers, and personalized coaching insights.

Better prompts come from deeper engineering knowledge

When you understand how real systems work, your prompts get sharper. Sponge tracks both so you can see the connection.

AI collaboration score tracked across sessions
42 average first session score, 82 average latest session score
+95% average improvement over 8 practice sessions

Get started in minutes

Pick a challenge, code with AI, get scored.

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