Mermail: agent inbox and wallet for signup, codes, and pay
Technical guide to Mermail (mermail.app) — private agent email (@mermail.to), user-controlled Agent Wallet via PayBox, MCP/API/CLI. Hermes OAuth setup, pricing, when to use vs AgentMail-style inboxes.
devrels.xyz/a/233short linkMermail (mermail.app) gives an AI agent a private email identity and a user-controlled Agent Wallet so it can finish web errands: sign up, receive verification codes, pay, and keep receipts — without borrowing your personal Gmail or raw card.
Public launch: Product Hunt · Mermail (Aug 15, 2026). Console: console.mermail.app. Docs: docs.mermail.app.
What you get
| Piece | Role |
|---|---|
| Agent email | Hosted address (e.g. *@mermail.to) or verified custom domain — registrations, OTPs, vendor threads, receipts |
| Agent Wallet | Delegated balances via PayBox — transfers, swaps, pay one selected x402 resource under standing grants / approval / signing policy you configure |
| MCP | One connection for email + wallet tools (ChatGPT, Claude, Cursor, Codex, OpenClaw, Hermes, …) |
| API / CLI / Skills | Mailbox automation, batch JSON, agent skills, task triage |
Control model (upstream docs): email side effects need explicit authorization. Payments stay inside PayBox policy — Mermail does not add a second approval layer.
Workflow
- Create inbox — hosted Mermail address or custom domain
- Connect AI — MCP, Agent Skill, or CLI
- Optional payments — connect PayBox → Agent Wallet for funding, transfer/swap, x402 under your limits
- Run errand — register → code from inbox → pay → archive receipt
Example use cases from product copy: buy domains under a cap, book services, pay small invoices, cancel subscriptions, vendor follow-ups, refund/support mail.
Hermes setup (Streamable HTTP + OAuth)
From mermail.app/integrations/hermes: interactive Hermes uses OAuth — do not put x-api-key on the interactive path. Use Streamable HTTP (POST), not SSE.
# ~/.hermes/config.yaml — merge under mcp_servers
mcp_servers:
mermail:
url: "<Mermail MCP Streamable HTTP URL from console>"
auth: oauth
# interactive: hermes mcp login mermail (fresh terminal; OAuth needs >30s)- Copy MCP URL from Mermail console
- Add server block; run
hermes mcp login mermailin a new terminal (in-session reload often too short for OAuth) - Authorize on console.mermail.app, pick workspace; tokens cache under
~/.hermes/mcp-tokens/ hermes chator/reload-mcp; try a mailbox list tool
Headless / jobs: drop auth: oauth, set headers.x-api-key: ${MERMAIL_API_KEY} from ~/.hermes/.env. Prefer MCP for interactive loops; CLI for batch JSON/JMESPath (non-interactive destructive flags need --yes).
Pricing (public site)
| Tier | Price | Highlights |
|---|---|---|
| Free | $0/mo | 1 inbox · 1k emails/mo · 1 GB · 10 API RPM · 1k API credits · hosted domain |
| Developer | Intro $1/mo then $19/mo | 5 inboxes · 10k emails · 10 GB · 100 RPM · 50k credits · custom domains |
| Enterprise | Custom | Volume, compliance, private deploy |
Confirm current numbers on the pricing page before budgeting.
When to use
| Use Mermail | Use something else |
|---|---|
| Agent must own signup email + OTP loop | Human-only inbox client (Upstream, etc.) |
| Same identity needs capped web pay + receipts | Inbox-only agent mail (e.g. AgentMail) if you already have payment rails |
| MCP agents (Hermes/Claude/Cursor) finishing errands | Pure on-chain x402 without email/OTP |
Related on DevRels: agent payment patterns in pay.sh / x402 pieces — Mermail is the identity + OTP + wallet shell, not a replacement for every merchant API.
Links
Summary
Mermail wires agent email and PayBox Agent Wallet so agents can complete signup → verify → pay → receipt under your policy. Connect via MCP (OAuth for Hermes interactive; API key headless), scale from free single inbox to Developer multi-inbox, and keep payment authority in PayBox grants — not in the model prompt.
Keep reading
Agents still hit APIs that want a human account and credit card. pay.sh turns 402 Payment Required into a one-line wallet-approved call on Solana stablecoins.
Paste https://api.paybox.sh/mcp into your agent. The user grants a wallet or card once. The agent gets signatures and payment artifacts — not seeds, not PANs.
OpenAPI-built trading tools were not enough. Agents still needed the prose: which operation, which constraints, which auth. Alpaca put that behind MCP too.
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