Rotating SMS API Keys Without Taking Login Offline

OTP security best practices cover bcrypt for codes and HTTPS for transport. This article focuses on a different secret: your SMS gateway API key—the credential that authorizes spend and sends. It complements, not duplicates, that guide.

Different From Hashing OTP Codes

User-facing OTP values are short-lived secrets you hash at rest. API keys are long-lived authentication to your provider. Leaked keys let an attacker send messages on your bill—see OTP fraud for attack patterns. Rotation reduces how long a stolen key works.

Dual-Key Cutover Pattern

If your dashboard allows creating a second key before revoking the old one, deploy in three steps: add new key to secrets store, roll pods or Lambdas to pick up new secret, verify traffic, revoke old key. Avoid big-bang restarts during peak login unless you run blue-green with both keys briefly valid.

Where Keys Live

Never commit keys to git. Use a secrets manager or encrypted CI variables. For local dev, document a fake key that points to mocks as in testing OTP in staging. Production keys should be readable only to the runtime role that calls your OTP API.

Leak Response Checklist

1. Revoke the compromised key immediately in the provider dashboard.
2. Issue a new key and deploy through your normal pipeline.
3. Review recent sends for anomalous countries or volume spikes.
4. Postmortem: how did the key leak—log, ticket, screenshot?

FAQ

See FAQ above.