API ReferenceOverview

API Overview

Authenticate with API keys, manage rate limits and credits, and explore Supasend's email sending, inbox, and dedicated IP endpoints.

Send and manage email with the Supasend API

Use the Supasend API to send email through connected Gmail, Outlook, or custom SMTP mailboxes. Manage inbox messages collected through IMAP polling, including replies, inbound messages, bounces, and automatic replies organized into threads.

Authentication

Authenticate every request with an X-API-Key header.

API keys use the format sk_live_<64 hex characters>. Keep your API key private and send it with every request to https://api.supasend.io.

Rate limits

Each API key supports up to 60 requests per minute.

Requests above the limit return HTTP 429. Add retry handling with backoff when your integration reaches the limit.

Credits

Each email send uses one credit. New accounts receive 100 free credits at registration.

Track your available credits before sending high-volume campaigns. The Credits endpoints provide usage and balance details.

Explore the API

Endpoint documentation is organized by tag in the sidebar:

  • Auth and API Keys: Authenticate requests and manage keys.
  • Send: Send email through connected mailboxes.
  • Mailboxes: Connect and manage Gmail, Outlook, and custom SMTP accounts.
  • Inbox: Retrieve classified messages and conversation threads.
  • Credits and Wallet: Review credit usage and account balance.
  • Logs: Inspect API activity.
  • Dedicated IPs: Manage dedicated IP resources.
  • Account: Manage account information.
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