Send branded email
Text and HTML from a verified sender.
Sender and branding
Use an active platform inbox address or a verified domain in the selected workspace. from is a bare address; from_name supplies its display name. text is required even with html. HTML is your branding, without an InboxIt marketing footer.
Delivery lifecycle
201 means accepted. pending means awaiting processing, queued means handed to delivery, delivered means remote server acceptance. It does not guarantee inbox placement. Native provider failures may appear as failed while emitting email.bounced.
Idempotency
Idempotency-Key is required: 1–100 letters, digits, underscores or hyphens. Reuse the same key and payload after an ambiguous timeout. A different payload with the same key returns 409. If the delivery status is uncertain, check the logs before sending again.
Outreach and unsubscribe
Set purpose to outreach for paced API delivery with unsubscribe controls. By default InboxIt adds a workspace unsubscribe footer and one-click headers. Use unsubscribe_url for your HTTPS preference page on an exact hostname verified in this workspace. The one-click header still uses InboxIt unless you also supply unsubscribe_one_click_url. A custom one-click endpoint must accept unauthenticated form POSTs with List-Unsubscribe=One-Click. Your backend must immediately call POST /workspace-suppressions with the recipient and reason unsubscribe, and stop your own follow-ups. Do not unsubscribe on GET: link scanners visit links. Use opaque recipient tokens, not exposed email addresses.
Integration controls
Use a separate workspace and scoped API key per customer. Domain, webhook and workspace-suppression APIs support explicitly granted scopes. POST /suppressions remains session-admin only and account-wide. GET /emails/:id reports status and next_attempt; POST /emails/:id/cancel cancels pending jobs only. Your campaign engine owns sequences, schedules, sender rotation and stop-on-reply. API outreach defaults to 50 sends per domain across the account in 24 hours, with 120 seconds between dispatches and a 24-hour queue expiry. Unlimited Enterprise volume does not remove these safeguards.
Content limits
One recipient. Subject up to 200 characters; text up to 10,000; HTML up to 80,000; display name up to 100. Up to five attachments, 2 MB each and 5 MB total. No CC/BCC, scheduled or batch sends. Quotas, suppressions and account verification apply.