Getting your API key
- Sign up at console.flowsbuilt.com
- Subscribe to the SDK you want (ChurnKit Free is automatic)
- Go to API Keys → Generate API Key
- Copy the key — it is shown once and never stored in plaintext
Key formats
| Prefix | Environment | Use for |
|---|---|---|
ck_live_ | Production | Live user data |
ck_test_ | Test | Development and CI |
Test keys send data to an isolated namespace — they never affect production metrics or fire production webhooks.
Using your key
Pass the key when constructing the SDK client:Keeping keys secure
- Store keys in environment variables (
.env, Railway secrets, Vercel env vars, etc.) - Rotate keys immediately if leaked — revoke the old key from the Console
- Use test keys (
ck_test_) in CI/CD pipelines - Create separate keys per environment (staging, production)