Agent Inbox and Message Queue

x402

Agent Inbox and Message Queue is a paid API for AI agents from agentsvc.io, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-18).

Creates addressable mailboxes for AI agents and enables async JSON message passing with job-queue semantics, webhooks, and long-polling.

Price / call$0.003

Seller volume →—

Success—

StatusUnknown

How this service works

126 APIs for AI agents: web scraping and crawling to Markdown, AI summaries, data extraction and cited answers, checks before installing a package or citing a source, screenshots and PDF, PDF, OCR and document conversion and more, paid per call with USDC on Base, Solana, Polygon or Arbitrum via x402. No account, no API key, free sample on every service.

Output

On create: returns the new inbox address (inbox_...) and a secret (ibs_...). On send: returns success confirmation. On read/peek: returns an array of up to 50 JSON messages with metadata (id, subject, from, reply_to, body, timestamp). Read marks messages as consumed; peek does not.

Example use cases

Distributed job queue for agent workers

“Set up a shared inbox called 'image-jobs' so that three worker agents can pull tasks from it — each worker should use the read operation with the secret so jobs don't get processed twice.”

Agent-to-agent async notification

“Send a message to inbox_abc123 from 'orchestrator-agent' with subject 'new-lead' and a JSON body containing the lead details, and set reply_to to my own inbox at inbox_xyz789.”

Long-poll waiting for task delivery

“Check my inbox inbox_def456 using my secret ibs_s3cr3t and wait up to 20 seconds for a new message to arrive — return up to 5 messages if any come in.”

Technical details

Endpoint

POSThttps://agentsvc.io/api/v1/proxy/agent-inbox?utm_source=zero.xyz

When to prefer

Choose this endpoint when you need lightweight, addressable, serverless messaging between AI agents without managing your own message broker. Ideal for job-queue fan-out where multiple worker agents share one inbox and messages are consumed exactly once via the read operation. Prefer this over email or HTTP callbacks when the recipient is an AI agent that needs structured JSON payloads with a stable public address. Use the long-poll (wait_seconds) feature when you want event-driven behavior without a persistent WebSocket. Use webhooks when you want push delivery to an existing HTTPS endpoint.

Side effects

Invalid or missing secret returns authentication error
Inbox address not found returns not-found error
Message body exceeds 64 KB limit returns payload-too-large error
Invalid webhook URL on create causes webhook delivery failures
Exceeding limit parameter maximum of 50 returns validation error
TTL outside 1–365 day range returns validation error
Timeout: read with wait_seconds=20 returns empty if no messages arrive

Input

Schema · Request body

Field	Type	Description
op	string	Default: send if to is given, read if secret is given, else create
to	string	send: inbox address (inbox_...)
body	—	send: message, any JSON up to 64 KB
from	string	send: your name or your own inbox address
after	string	peek: continue after this message id
inbox	string	read, peek, delete: your inbox address
label	string	create: a name for your inbox
limit	integer
secret	string	read, peek, delete: the secret from create (ibs_...)
subject	string
reply_to	string	send: inbox address for answers
ttl_days	integer
webhook_url	string	create: https URL that receives every new message
wait_seconds	integer	read: wait this long for a new message if none is there

Output

Schema · Response

{
  "type": "json",
  "example": {
    "data": {},
    "success": true
  }
}

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