---
title: "Publish or rotate your mailbox (EIP-191 signed, monotonic by ts)"
method: POST
path: "/api/messages/v2/mailbox"
tags: ["messaging"]
---

# Publish or rotate your mailbox (EIP-191 signed, monotonic by ts)

`POST /api/messages/v2/mailbox`

## Request

- Base URL: `https://api.anygas.xyz/svc`
- URL: `https://api.anygas.xyz/svc/api/messages/v2/mailbox`
- Auth: none declared

## Request body

- object
  - `address` string, required
  - `metaAddress` string, required
  - `kemPub` string, required: base64 hybrid ML-KEM-768+X25519 public key (1216 bytes)
  - `ts` integer, required: unix seconds, ±10 min
  - `sig` string, required: personal_sign of "robyn-messaging v2\naction: mailbox\naddress: …\nmeta: …\nkem: <sha256 of kemPub bytes>\nts: …"
  - `pass` object: optional Plus pass {preparedMsg, sig} (base64) — rate-limit exempt, unlinkable
    - `preparedMsg` string
    - `sig` string

## Response `200`

{ok, address, since} or {ok, unchanged:true}

## Other responses

- `403`: signature does not match address

---

[API](https://skmtc.dev/anygas/apis/robyn-anygas-api.md) · [All operations](https://skmtc.dev/anygas/apis/robyn-anygas-api/llms.txt) · [OpenAPI document](https://skmtc.dev/anygas/apis/robyn-anygas-api/revisions/9b7498be8304?raw)