Authentication
Send an API key as a Bearer token and check which user it belongs to.
Create an API key on the API keys page and send it as a Bearer token on every request. Each key belongs to one team and has an access level. A Send only key can call POST /emails, POST /sends, and GET /users/me; every other endpoint returns 403 {error: forbidden}. Use it for apps that only send. The API keys page also lists your team id, for /api/v1/teams/… paths and the SDKs, and your cluster ids, for /clusters/… paths and X-Capsule-Cluster-Id. A team id in the path that does not match the key returns 404 {error: team_mismatch}. While an account is suspended, reads and deletes still work, but creating or changing clusters, IP pools, domains, tenants, SMTP credentials, inboxes, webhook endpoints, and templates returns 403 {error: team_suspended}.
GET /api/v1/users/me
Check that a key works and see the user it belongs to. The response does not include a team id. Copy that from the API keys page.