CRIER
a Vima Brosta LLC service · manual · received a message?
§ · message relay · for AI agents

Your agent finished. Someone has to hear about it.

Crier delivers an email, an SMS, or a signed webhook from an AI agent to a person or a system, and keeps retrying for hours after the agent's session is gone. No mail server, no phone number, no account, no API key: one x402 micropayment per message, refused before payment whenever it cannot run.

base url https://crier.vimabrosta.com auth none; no accounts, no keys payment x402, per message, USDC on Base or Solana

01Three ways out

Agents end. The people and systems they work for do not. Each channel below is one purchase: the relay accepts the message, settles the payment, sends within seconds, and retries on a fixed ladder if the other side is down. A free status endpoint says what happened.

Tariff. One purchase per message; nothing recurs.
channelcaps per destinationprice
Emailsubject, text (HTML optional), reply-to; sent from the relay's address with a footer and an unsubscribe link 4 per hour · 12 per day$0.01
SMSan E.164 number, up to 300 characters; sent from the relay's number with an opt-out suffix 2 per hour · 6 per day$0.05
WebhookJSON or text to a public URL, POST or PUT, HMAC signed; retried at 30 s, 2 m, 10 m, 1 h, 6 h 600 per hour per host$0.005

02How a message is bought

  1. Send the request with no payment. The 402 lists every accepted payment option and, if the request would be refused, says so before you pay.
  2. Pay and retry the identical request with the X-PAYMENT header and an Idempotency-Key. A network retry can never send or charge twice.
  3. Receive 202 with a delivery id and a one-time secret. The message goes out within seconds; GET /v1/deliveries/{id} reports sent, failed, or still queued.
POST /v1/emailapplication/json
{
  "to": "person@example.com",
  "subject": "Your order 42 shipped",
  "text": "Tracking number 1Z999. It arrives Thursday.",
  "reply_to": "ops@your-company.example",
  "from_name": "Order Desk"
}
# 202
{"id":"dl_…", "secret":"dls_…", "status":"queued", "to":"p***@example.com", "receipt":{"price":"$0.01"}}

03What the recipient sees

A relay that can be mistaken for the sender is a relay that gets blocked. So every email is delivered from crier@vimabrosta.com as "name via Crier", with a footer naming the relay and an unsubscribe link; every SMS comes from Crier's own number with "reply STOP to opt out" appended. An agent may set a display name and a reply-to address, and nothing else about who it appears to be.

An address that bounces, complains, replies STOP, or unsubscribes goes on a list Crier will never write to again, for any agent, and a request to send there is refused before payment. A person who wants to know what they received starts at /received.

04What Crier keeps, and does not do

  • The destination and the content are held only until a delivery is final, then deleted. What remains for 7 days is a masked destination, hashes, and the status.
  • Content is never read for meaning, scored, or used for anything but delivery.
  • Per-destination caps are enforced before payment, so no agent can turn the relay on one person.
  • Webhook receivers must be public; private, loopback, and internal addresses are refused, and resolution is re-checked at connection time.
  • The sender is responsible for having a lawful reason to contact the people it messages. Crier is for messages a person expects from an agent working for them or with them, not for bulk marketing; the caps make bulk impossible by construction.

05Interfaces

Machines first. Everything on this page is available at a fixed address in a form an agent can read on a token budget.

06Asked before you ask

What is Crier?

Crier is a pay-per-message relay for AI agents. An agent hands it a destination and a message, pays one micropayment, and Crier delivers the email, SMS, or webhook, retrying for hours if the receiver is down, after the agent's session has ended.

How does an AI agent pay?

Through x402. The agent sends the request, receives HTTP 402 with the exact price and the accepted networks, pays with USDC on Base or Solana, and retries the same request. There is no account, no API key, and no subscription.

What does it cost?

An email is $0.01, an SMS is $0.05, a webhook is $0.005. Each is one purchase; a request that cannot run is refused before payment and costs nothing.

I received a message. Who sent it?

An AI agent run by someone who knows your address. Crier carried it; it did not choose you and does not read what it relays. Every email carries an unsubscribe link and every SMS says reply STOP; either stops every agent that uses the relay, permanently.

Can an agent spoof a sender?

No. Every email is sent from Crier's own fixed address with a footer naming the relay, and every SMS from Crier's own number. An agent may set a display name and a reply-to address, and that is all.

What does Crier keep?

The destination and the content only until the delivery is final, then they are deleted. A masked destination, hashes, and the status remain for 7 days. Addresses that opted out are kept, hashed, so they are never written to again.

How do agents find Crier?

Through the x402 Bazaar catalog, /llms.txt, the OpenAPI document, and the MCP endpoint. Crier is operated by Vima Brosta LLC, which also runs Stumble (watches, wakes, and crons for agents) and Umpire (signed verdicts and reputation).

07Terms, in short

Messages are one-time micro-purchases, accepted or refused before payment settles, and not refundable at these prices. Crier relays; acting on a message, and having the right to send it, are the sender's responsibility. Recipients who opt out are honored for every sender. Service is provided as-is by Vima Brosta LLC. The full terms are at /terms; questions and opt-out requests go to contact@vimabrosta.com.