Write the failing tests first.
Ship the passing code faster.
Paste a feature spec or a function signature. RedSpec generates a complete red test suite — Jest, Vitest or Pytest, auto-detected — then scaffolds the minimal implementation to make it green. Real TDD ordering, enforced.
npx redspec gen ./spec.md
Your failing test suite appears here. These tests should fail first — that's the point.
Free tier: 5 generations/month. No signup to try the demo.
From spec to green in three steps
RedSpec enforces the discipline most "AI test" tools skip: the tests come first, and they fail first.
1. Paste your spec
A description, a function signature, an acceptance-criteria list — anything. RedSpec auto-detects your framework from package.json or pyproject.toml.
2. Get a red suite
A complete, idiomatic test suite covering happy path, edges, and errors — that fails because the code doesn't exist yet. That's correct TDD.
3. Go green
Write the code, or let RedSpec scaffold the minimal implementation. Watch coverage climb as each test flips from red to green.
Why RedSpec, not a "write me a test" prompt
Real TDD ordering
Tests are generated to fail first and are tracked through red → green. No skipped steps, no expect(true) filler.
PR bot (Pro)
Connect your repo and RedSpec comments on every pull request with the exact missing-test gaps and a coverage delta.
Framework-aware
Jest, Vitest, and Pytest today — detected automatically. Idiomatic describe/it blocks and pytest classes.
Coverage deltas
Every run reports which behaviors are now covered, so you know the suite actually specifies the spec.
Open-source CLI
npx redspec runs in your terminal and CI. The hosted PR bot is the only paid piece.
Your code stays yours
Specs are sent for generation and not retained for training. Bring-your-own-key supported in the CLI.
Simple pricing
Start free in your terminal. Upgrade when you want the PR bot watching your repo.
Free
- Open-source CLI
- 5 spec-to-suite generations / month
- Jest · Vitest · Pytest
- Coverage targets per run
Pro
- Unlimited generations
- GitHub PR bot — missing-test gaps on every PR
- Coverage-delta tracking
- Priority generation
- Email support
Founding members lock in $19/mo for life. No spam, unsubscribe anytime.