postfleet

Secure email infrastructure for AI agents.

CommunityOnlineAPI key requiredGlobalFreeCan modify data

What it can do

List Mailboxes: List the mailboxes you can use, newest first, each with its id and email address. Call this when you need a mailbox_id for any other tool, or to check whether you already have a mailbo
Create Mailbox: Create a NEW email mailbox this agent owns. Call this when list_mailboxes shows you have no suitable mailbox yet — mailboxes persist across sessions, so creating a second one for the s
List Domains: List the account's custom sending domains with their id, name, and verification status. Call this when you want to create a mailbox on a custom domain (pass the id of a verified domain a

What data it sees

Do you need an account

An API key from the service settings is required

Secure email infrastructure for AI agents. Every inbound message is verified, sanitized, and screened for prompt injection before your agent reads it — hidden HTML, zero-width characters, and decode-then-apply payloads are stripped or fail closed — then delivered as typed JSON. Outbound send is idempotent, with optional human approval on consequential replies.

Server tool list (14)

Raw names from tools/list. Only developers need these.

list_mailboxes	List the mailboxes you can use, newest first, each with its id and email address. Call this when you need a mailbox_id for any other tool, or to check whether you already have a mailbox before creating one — it is usually the first call in a workflow. Returns every mailbox on the account, or just your own if your API key is scoped to a single mailbox. An empty list means you have none yet — use create_mailbox.
create_mailbox	Create a NEW email mailbox this agent owns. Call this when list_mailboxes shows you have no suitable mailbox yet — mailboxes persist across sessions, so creating a second one for the same purpose strands mail in the first. Returns a working address immediately. Optional slug personalizes the address (agent-<slug>@...). To create the mailbox on a custom domain instead of the shared one (<slug>@yourdomain.com), pass a domain_id from list_domains — the domain must be verified.
list_domains	List the account's custom sending domains with their id, name, and verification status. Call this when you want to create a mailbox on a custom domain (pass the id of a verified domain as create_mailbox's domain_id), or to check whether a domain has finished verifying. Only status "verified" domains can host mailboxes; an empty list means only the shared platform domain is available.
send_email	Send a new email from one of your mailboxes. Call this when starting a NEW conversation; to answer an email you received, use reply_email instead (it threads correctly). Pass a client_id (any unique string you make up) and reuse the SAME client_id if you retry after an error — that guarantees the email is sent at most once. If the mailbox requires human approval, the send is queued as a draft and returns {draft_id, status:"pending_approval"} instead of a message id — that is NOT a failure and must NOT be retried; the email goes out once a human approves it (check with list_drafts).
reply_email	Reply to an email you received. Call this when answering an existing message — recipient, subject, and conversation threading are derived automatically from the original. Pass a client_id (any unique string you make up) and reuse the SAME client_id if you retry after an error — that guarantees the reply is sent at most once. If the mailbox requires human approval, the reply is queued as a draft and returns {draft_id, status:"pending_approval"} instead of a message id — that is NOT a failure and must NOT be retried; it is sent once a human approves it (check with list_drafts).
list_inbox	List recent messages in a mailbox, newest first, with comprehension status per message. Call this when checking what has arrived; use read_email for full content and extracted data.
read_email	Read one email in full: cleaned body, sanitization report (screened against known hidden-content patterns), classification, and data extracted to the mailbox schema. Call this when you need the content or extraction of a specific message.
wait_for_email	Block until a matching email arrives in a mailbox (or time out). Call this when you just sent an email and need the reply, or are expecting an inbound message — instead of polling list_inbox yourself. Returns the full message on match, or {timed_out:true}.
create_draft	Prepare an email as a draft without sending it. Call this when you want to stage a message for later or for a human to review before it goes out — send it afterward with send_draft. Same fields as send_email, or omit to/subject and pass reply_to_message_id to draft a threaded reply. Returns the draft id with status "draft".
list_drafts	List the open drafts in a mailbox (status draft, pending_approval, or sending), newest first. Call this when you need to see messages you have staged or that are queued waiting on human approval, e.g. after a send returned status "pending_approval".
get_draft	Read one draft in full by its id: recipient, subject, body text, and current status. Call this when you need the content of a specific draft — e.g. to review what is queued for approval after list_drafts, or before editing it with update_draft.
update_draft	Edit the to, subject, or text of a draft that has not been sent yet — omitted fields keep their current value. Call this when a draft needs changes, e.g. a human declined to approve it and you are revising it. The reply target cannot be changed (create a new draft to reply to a different message), and a draft that is already sending or sent can no longer be edited.
send_draft	Send a draft you prepared, by its id. Call this when a staged draft is ready to go out. If the mailbox requires human approval, this returns 202 {draft_id, status:"pending_approval"} — the draft is queued for a human to approve, which is NOT a failure and must NOT be retried; it is sent once approved. Otherwise it sends immediately and returns the message id.
delete_draft	Discard a draft by its id so it will never be sent. Call this when a staged or pending-approval message should be withdrawn — e.g. it is no longer needed or was created by mistake. A draft that is already sending or sent cannot be deleted.