paperplane vs. Lob

If you are evaluating mail-sending APIs, you have probably already found Lob — it is the incumbent in this space. This page is not a sales pitch dressed as a comparison. paperplane and Lob solve overlapping but genuinely different problems, and the honest answer to "which one should I use" depends on what you are sending, how often, and whether a human or an AI agent is driving the send.

Where paperplane is different

Three things are real, verifiable differences today, not marketing claims:

• No account, no API key, for a single letter. Lob's model is a provisioned account: you sign up, generate an API key, and manage it like any other cloud credential before your first send. paperplane lets you send one letter by paying per-use through a Stripe checkout link, or by buying a prepaid credit code up front — no account object exists for a one-off send. This matters if you need to mail something once, or if you are prototyping an integration and do not want a credential to provision and rotate yet.
• A real MCP server for AI agents. paperplane exposes an MCP endpoint at /api/mcp (see app/api/[transport]/route.ts in the codebase) with three tools — quote_letter, send_letter, and get_letter_status — so an agent running in Claude Desktop, Claude Code, or another MCP-speaking host can quote and mail a letter without any custom wrapper code. Lob does not currently publish an MCP server; an agent built against Lob has to go through a hand-written REST or SDK integration instead. Full details on the quote-then-send safety pattern are on the MCP mail guide.
• One all-in price. paperplane starts at $1.99 all-in for First-Class, postage, printing and the envelope included, with the same number on the pricing page, in the quote and on the receipt. Lob's pricing is published as per-piece rates with postage on top, tiered by volume.

Where Lob is ahead

A comparison that only lists paperplane's advantages would not be a comparison worth trusting. Two gaps are real and worth stating plainly:

• Official SDKs in 8 languages. Lob ships maintained client libraries for TypeScript/Node, PHP, Java, Python, Ruby, Elixir, C#/.NET, and Go, plus frontend address-verification widgets. paperplane does not have official SDKs yet — today it's REST (POST /v1/quotes, POST /v1/orders) or MCP, both callable from any language, but without a generated, idiomatic client library. SDK generation is planned but not shipped.
• Postcards, checks, and international mail at production scale. Lob supports these today, with the volume and reliability track record of a mature platform. paperplane sends letters only — First-Class, Certified, Certified + electronic Return Receipt, and Priority, domestic only. If your use case is postcard marketing, check disbursement, or mailing outside the US, paperplane is not the right tool yet.

Side-by-side

Which one actually fits

If you are sending postcards or checks, mailing internationally, or you already have a mature mail-sending pipeline built against Lob's SDKs, switching would be a step backward — Lob covers that ground and paperplane does not. If you need to send one Certified Mail letter today without creating an account, or you are wiring mail into an AI agent that speaks MCP, paperplane is built for exactly that. Some teams end up using both: Lob for bulk, multi-format campaigns, and paperplane for the occasional one-off letter or an agent workflow that should not need a provisioned API credential to send its first piece of mail.

Pricing above is current paperplane retail: First-Class $1.99, Certified Mail $12.99, Certified + electronic Return Receipt $14.99, Priority Mail $24.99. Lob pricing is set by Lob and not reproduced here — check lob.com for their current rates.