A Lob / PostGrid alternative built for AI agents

If you've looked at putting physical mail behind an AI agent, you've probably found Lob or PostGrid. They're good — genuinely good — but they were built for engineering teams wiring direct mail into an application, not for an agent that wants to send one letter, right now, without a procurement step. That mismatch is the whole reason Mailsnail exists.

Here's the honest comparison, and when each one is the right call.

Where Lob and PostGrid are strong

Credit where it's due. Lob and PostGrid are mature direct-mail APIs with excellent address verification — Lob covers 240+ countries — plus webhooks, sandboxes, and the throughput an enterprise mail program needs. If you're a team shipping statements or campaigns at volume and you already live in API keys, they're a solid choice, and this page isn't trying to talk you out of them.

Where they get in an agent's way

The friction shows up the moment the sender is an agent rather than a backend team:

• You need an account and API keys first. An agent can't self-serve past a signup wall and a key vault.
• Minimums and monthly fees. Lob's lower-cost tiers carry a monthly platform fee — fine when you amortize it over volume, dead weight when you want a handful of pieces per event.
• No first-party MCP server. Neither exposes an official MCP surface, so an agent reaches them only through community wrappers you have to trust and maintain.
• Pricing you have to look up. An agent deciding whether a send is worth it wants the number inline, not a tier table.

The comparison

	Mailsnail	Lob	PostGrid
No signup / no keys for the agent	✅	❌ account + keys	❌ account + keys
Official MCP server	✅ npx -y mailsnail	❌ community wrappers	❌ community wrappers
Pricing	Flat & public — $1.50 letter, $9 certified, $1 postcard	Per-piece + monthly fee on lower tiers	Per-piece, account-based
Pay-per-piece, no monthly minimum	✅	⚠️ tier-dependent	⚠️ tier-dependent
Address verification	✅ USPS CASS	✅ CASS + 240+ countries	✅ CASS + international
Certified mail	✅ $9, one flag	✅ (enterprise)	✅
Open-source / provider-agnostic	✅	❌	❌
Best for	An agent sending real mail with no setup	Enterprise direct-mail at scale	Account-based direct-mail + verification

You don't have to fully switch

If you already have a Lob key and want to keep Lob's fulfillment, you can — Mailsnail is provider-agnostic. Run it in managed mode for the no-signup default, or point it at your own Lob or Click2Mail credentials and keep Mailsnail purely as the agent-facing MCP layer. Because the core is open-source, you can read exactly how the money and the mail move before you trust it with either.

When to pick which

• Pick Lob if you're an enterprise running high-volume direct mail and you need the broadest global address verification.
• Pick PostGrid if you want an account-based direct-mail API with strong verification, built into an app rather than an agent.
• Pick Mailsnail if the thing sending the mail is an agent, you want a price you can read off the page, and you'd rather have a letter in the mail in minutes than an account approved by Friday.

Related guides

• How to send physical mail from an AI agent — the umbrella how-to.
• Send a letter from Claude, Cursor, or Codex — per-client setup.

{
  "mcpServers": {
    "mailsnail": {
      "command": "npx",
      "args": [
        "-y",
        "mailsnail"
      ],
      "env": {
        "MAIL_PROVIDER": "managed",
        "MAIL_API_BASE_URL": "https://api.mailsnail.dev"
      }
    }
  }
}