KeyKeeperFOR DEVELOPERS
One mail service. More ways to build.
Use REST or MCP to give your application a real mailbox. We’re growing that foundation into a lightweight transactional email service on our own infrastructure.
New agents can receive mail immediately and start with zero sending credits. Sending requires existing credits; new funding is paused. Broad transactional sending is being prepared for a controlled pilot.
BUILD AGAINST THE CURRENT API
Your mailbox is
a programmable interface.
Create an agent account for your integration. Use its key to list and read incoming mail. Accounts with existing credits can submit messages, including attachments, from their own mailbox address.
- Keep the key on your serverDo not embed it in public frontend code or URLs.
- Make retries safeReuse the same Idempotency-Key and identical payload after a timeout.
- Account for recipientsOne credit per accepted recipient. Sending is capped per account.
Send with existing credits
curl --fail-with-body https://keykeeper.world/api/v1/agent/send \
-H "Authorization: Bearer $KEYKEEPER_API_KEY" \
-H 'Content-Type: application/json' \
-H 'Idempotency-Key: unique-message-001' \
-H 'User-Agent: MyAgent/1.0' \
-d '{"to":"[email protected]","subject":"Hello","body":"A message from my agent."}'An accepted response means SMTP accepted the message. It is not a delivered event. If the outcome is unknown, keep the original key and reconcile before trying a new send.
TOWARD A RESEND ALTERNATIVE
A useful pilot comes before
a broad sending launch.
The first pilot will use KeyKeeper’s own account and security notifications. These are the readiness gates.
| Capability | Current state |
|---|---|
| Mailbox registration, receiving and reading | Available |
| Authenticated REST / MCP sending | Existing credits required |
| Recipient accounting and idempotent retries | Available |
| Scoped developer keys and sender controls | Next milestone |
| Delivery events, bounce handling and suppressions | Next milestone |
| Custom domains with per-domain DKIM | In development |
| Unrestricted developer onboarding and new funding | Not open yet |