Idempotency Keys

To avoid sending duplicate emails when retrying failed requests or handling at-least-once webhooks (e.g. Stripe checkout completion), include an Idempotency-Key header.

How It Works

You supply a unique key (such as checkout_session_12345 or a UUID) in the Idempotency-Key HTTP header.
If Mailofly receives another request with the identical key within 24 hours, it returns the existing message result instead of dispatching a second email.

curl -X POST "https://api.mailofly.com/api/emails" \
  -H "Authorization: Bearer mf_live_..." \
  -H "Idempotency-Key: invoice_98765" \
  -d '{ ... }'

Related topics

Manage API Keys API Key Security Leaked API Keys Create API key SDKs

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