API keys authenticate applications, scripts, mail clients, and automation. Keys are shown once when created or rotated, so store them in your secrets manager immediately.Documentation Index
Fetch the complete documentation index at: https://docs.sendmux.ai/llms.txt
Use this file to discover all available pages before exploring further.
Key types
| Key type | Use it for |
|---|---|
| Infrastructure key | Team automation, providers, routing, billing, logs, domains, mailboxes, and webhooks. |
| Sending key | Sending mail through the Sending API, SMTP, CLI tools, MCP clients, or agents. |
| Mailbox key | API, IMAP, and SMTP access for one mailbox. |
Each team starts with 100 active API keys across all key types. See Team
limits.
Create a key
Choose the key type
Select Create API Key, then choose the key type. Sending keys can route
through all providers, selected providers, or delivery groups.
Scopes and presets
Infrastructure keys use role presets such as Full Access, Read Only, Provider Admin, Billing Admin, and Webhook Admin. Sending and mailbox keys use mailbox permissions:| Permission | Allows |
|---|---|
email.send | Send email through HTTP or SMTP. |
email.receive | Receive email through mailbox access. |
mailbox.read | Read mailbox folders and messages. |
mailbox.settings.update | Update mailbox identity and settings. |
Rotate a key
Use rotation when a key may have leaked, when a team member leaves, or as part of regular credential hygiene.- Select the rotate action beside the key.
- Copy the new secret when it appears.
- Deploy the new secret to every system that uses it.
- Revoke the old key once all callers have moved.
Revoke a key
Revocation is immediate. Any system still using the key loses access. Create and test a replacement before revoking a production key. Mailbox keys also stop working while their mailbox is suspended, and work again after the mailbox is resumed.Related guides
Send by HTTP
Use a sending key to queue messages through the API.
Delivery groups
Route sending keys through selected provider groups.
Mailboxes
Create mailbox keys and per-integration passwords.
API errors
Handle authentication, permission, and rate-limit errors.