Deliverability & limits
An Extrovert inbox is a real account an agent can use for sign-ups, replies, notifications, and reviewed outbound mail. Extrovert provides authenticated sending and a rolling limit so one inbox cannot consume unbounded shared capacity.
Authenticated sending
Section titled “Authenticated sending”Every inbox is registered as an authenticated sender when it is created. Extrovert publishes or verifies the required SPF, DKIM, and DMARC records for the sending domain. NS-delegated domains let Extrovert serve those records and MX directly.
Authentication makes the sender legitimate; it does not guarantee inbox placement. Content, recipient expectations, complaints, bounces, and domain history still affect delivery.
Per-message limits
Section titled “Per-message limits”Aim for about 1 MB of attachment files in total with a short message body. Encoding makes the files larger, and large bodies leave less room for attachments.
Each email may contain at most 50 combined To/Cc/Bcc recipients and 20 attachments. The complete encoded message must fit within 1,800,000 bytes, including headers and text/HTML bodies. See size examples and error responses.
The rolling send limit
Section titled “The rolling send limit”The volume control is a per-inbox rolling 24-hour recipient limit.
| Setting | Current behavior |
|---|---|
| Default | 75 recipients per rolling 24 hours |
| Configuration | daily_send_limit on the inbox |
| Allowed range | 1-10,000 |
| Required permission to change | mailbox:quota |
| Over the limit | 429 with Retry-After |
The limit counts recipients, not API calls. A single message addressed to multiple people consumes capacity for each recipient.
Review and suppression controls
Section titled “Review and suppression controls”Free-plan outgoing messages include an Extrovert promotional footer. Text and HTML versions of the same message carry the same promotion, and the footer appears in the platform’s Sent copy. Paid-plan messages do not carry this footer.
If a free-plan message cannot be prepared for sending, the request returns
503 unavailable or the reviewed send reports a delivery failure. Nothing is
submitted for delivery on that attempt; retry after the service recovers.
Agent-plane sends follow the effective review policy. A queued response means nothing was delivered yet. Suppression and contact-list checks run before release, and subscribed bulk mail can receive unsubscribe headers when that feature is configured.
Direct SMTP enters the Review Loop and enforces recipient restrictions, suppression, unsubscribe policy and platform accounting. SMTP acceptance means custody; a required review waits for approval in the review thread before delivery. It is disabled per inbox by default and can be enabled by a customer administrator or an explicitly authorized Full account control connection within current human roles, for a paid account. Exported credentials do not grant SMTP submission on their own. API, SDK, and MCP sends continue through the Review Loop regardless of this setting.
Inspect current status
Section titled “Inspect current status”Use get_deliverability_status for the current organization rollup and
list_deliverability_findings for bounded, actionable findings. The console groups these under
Deliverability with health and suppression views. Treat provider-specific diagnostics as internal;
public errors and instructions describe the condition and recovery action without exposing the
underlying sending vendor.
Reputation isolation
Section titled “Reputation isolation”Domains and delegated subdomains have their own authentication configuration. Use separate domains when workloads require independent operational or reputation boundaries; do not assume the platform dynamically scores or reroutes senders.