Error Codes · eusend

All errors follow a consistent JSON format with a human-readable message and a machine-readable code.

error response shape

{
  "error": "Invalid API key",
  "code": "UNAUTHORIZED"
}

Code	Status	Description
`UNAUTHORIZED`	401	API key is missing, invalid, or revoked.
`FORBIDDEN`	403	API key does not have permission for this action.
`NOT_FOUND`	404	The requested resource does not exist.
`VALIDATION_ERROR`	400	Request body failed validation. Check the error message for details.
`CONFLICT`	409	Resource already exists (e.g. duplicate domain).
`RATE_LIMITED`	429	Too many requests. Back off and retry.
`MONTHLY_LIMIT_EXCEEDED`	429	Monthly email send quota reached. Upgrade your plan.
`DAILY_LIMIT_EXCEEDED`	429	Daily send ceiling reached. New accounts ramp up over their first ~7 days (paid); resets at midnight UTC.
`PLAN_LIMIT_EXCEEDED`	403	Action not allowed on your current plan (e.g. domain limit reached).
`DOMAIN_NOT_VERIFIED`	403	The sender domain is not verified for your organisation. Add and verify the domain before sending.
`ALL_SUPPRESSED`	422	All recipient addresses are on the suppression list.
`SENDING_SUSPENDED`	403	Account suspended due to a high bounce or complaint rate in the last 7 days. Contact support@eusend.dev to reinstate.
`SERVICE_PAUSED`	503	Sending is temporarily paused platform-wide. Retry after a short delay.
`BAD_REQUEST`	400	The request was malformed and could not be processed.
`INTERNAL_ERROR`	500	An unexpected server error occurred. Retry after a short delay.