POSTBOX / EARLY ACCESS Built for agents. Controlled by you.
Give your agent its own email identity, the context you want it to keep, and the access it needs to work. One workspace. Every conversation connected.
Save this article with our research. The section on memory is the part I want to come back to.
Source text, sender notes, and explicit memories stay distinct. Your research keeps its context.
Your agent can find the saved article and read its source when you ask it to revisit the research.
search_context{ "inbox_id": "research",
"query": "memory" }
Illustrative workflow · no email sent or account connected
01 / THE WORKSPACE
Read the mail. Curate the context.
Decide what your agent can access.
This is the article I mentioned. The section on…
Three ideas worth keeping in mind.
A home for the next conversation.
Maya to Research assistant
This is the article I mentioned.
The section on long-term memory feels especially relevant. Keep it with our research so we can come back to it.
— Maya
Saved with your note and original source.
A home for related ideas.
Explicit context, chosen by you.
Save articles, organize research into collections, and keep the preferences you want your agent to remember.
“The section on long-term memory is relevant to our next project.”
research@example.test
A separate place for credentials.
Never mixed into knowledge.
Keep website credentials attached to the inbox they belong to, with explicit, audited password reveals.
••••••••••••••••
02 / CONTINUITY, WITH CONTROL
A place for what your agent needs.
A clear boundary around what it can do.
Turn articles and conversations into a source-linked library. Add the preferences you explicitly want remembered.
research@agent.exampleA dedicated inbox with threads, replies, attachments, drafts, and scheduled sends. Managed like email should be.
Keep website credentials in their own vault. Reveal them explicitly, under manage permission, with an audit record.
Delegate inbox scopes, require approval before sending, and revoke access when the job changes.
03 / BUILT TO CONNECT
The work you manage here is available to your agent through the REST API and MCP. Mail, knowledge, credentials, and access share the same permission boundaries.
Read the MCP guide ↗POST /v1/inboxes/{inbox_id}/messages
Authorization: Bearer YOUR_SCOPED_TOKEN
Idempotency-Key: YOUR_UNIQUE_REQUEST_ID
Content-Type: application/json
{
"to": ["you@example.com"],
"subject": "A thought worth keeping",
"text": "Here’s what I found…"
}One inbox. Scoped access. Repeatable requests.
A FEW THINGS TO KNOW
Yes. Postbox currently ships as a local-first application. The workspace connects using an inbox ID and scoped token. Local delivery is simulated; no external email is sent.
A deployed API and worker, durable storage, a configured SendGrid account and sending domain, and production identity configuration. Live provider setup is separate from the local workspace.
Not yet. Customer signup, team management, and subscription billing are planned SaaS work. The workspace available today is for configured inboxes; opening it does not create a hosted account.
Vault access is scoped to an inbox and requires manage permission. Read and send permissions do not grant vault access. Reveals are explicit and audited; credentials are not included in knowledge search.
MAKE ROOM FOR WHAT’S NEXT
Local-first today. Built with API and MCP access from the start.