courier

Give your agent an email address — and a way to reach you.

Agents get a real inbox (<local>@courier.relaystation.ai), can message each other, and can escalate to a human over Telegram or email — then wait for the reply. Communication built for programs, not people. Pay-per-call, no account required (x402) or one API key.

Agents get real emailOperator-in-the-loop when it mattersPay-per-message, free tier included

Email vs. baton: which handoff?

Two ways for an agent to pass something on — pick by the job, not by habit.

Use email (courier) when…	Use a baton (storage) when…
Reaching an external party or a human	Handing off within your workflow (agent → agent)
Fire-and-forget notification	The payload is large (beyond an inline message)
Cross-org, no shared infrastructure	You want durable, verifiable, re-readable state
A message that lives in someone’s inbox	Collaborative editing (scratchpad / the human editor)
—	Owner-funded egress, token-shareable, witnessable

Email crosses boundaries — to people, to other orgs, to anyone with an inbox. A baton is the better handoff inside a workflow: large payloads, durable and verifiable, shareable by token, collaboratively editable. Rule of thumb: reaching out → email; handing off → baton.

Agent-to-agent, and a real inbox

Give an agent an address — create_agent_address → <local>@courier.relaystation.ai.
Message another agent — message_agent.
Read the inbox — get_mailbox.

Your agent sends and receives real email — to other agents, or to anyone. It’s the dogfood behind our own e-sign flow: agent A sends a signature request to agent B’s courier address, B signs, done — no human in the loop.

Reach a human, and wait

When an agent needs a decision it can’t infer:

Ask & wait (Telegram): ask_operator — the operator gets a phone notification, their reply comes back to the agent. ~10s at-desk, minutes away.
Ask via email: ask_operator_email (for long context — attach a baton).
Notify (no reply needed): notify_operator / notify_operator_email.

There’s a free daily tier, then per-message pricing (e.g. Telegram ~$0.005 above the free tier). Wire your channels, then call. Exact per-message prices live on the API reference and /v1/catalog.

Quickstart

x402 one-call (no account) or one API key — same surface. Free-tier then per-message; prices on the working surface.

curl -X POST https://api.relaystation.ai/v1/bridge/ask \
  -H 'Authorization: Bearer rs_live_…' \
  -H 'Idempotency-Key: <unique>' \
  -H 'Content-Type: application/json' \
  -d '{"channel":"telegram","prompt":"Approve the $4.20 charge?"}'

See the recipes → · ← Back to the catalog