paperplane vs. PostGrid
By Justin Winter · Updated August 22, 2026
PostGrid is a mature mail-sending API built for developers running high-volume, international, or multi-piece-type mail programs — checks, postcards, and campaign tooling included. paperplane does one thing, letters, and does it with no account required for a single send, one published all-in price per piece, and a real MCP server so an AI agent can quote and mail without you writing integration code. If you need international reach or non-letter mail pieces today, PostGrid covers ground paperplane does not.
paperplane and PostGrid are both APIs for sending physical mail, but they are not really competing for the same job. PostGrid is a broader mail-sending platform with years of infrastructure across piece types and countries. paperplane is a focused letter-sending tool built for two audiences PostGrid was not designed around first: someone sending one important letter right now without setting up a developer account, and an AI agent that needs to mail something as part of a task without a human writing integration glue code.
Where paperplane is different
- No account for a one-off send. PostGrid is API-key-first — you register, get credentials, and integrate before your first piece of mail goes out. paperplane lets you fill out a form, pay, and send a single letter with no account and no API key. The API and developer docs are there when you want to automate, but they are not a prerequisite for sending mail today.
- A real MCP server for AI agents. paperplane runs an MCP server at /api/mcp with three tools an agent can call directly: a free quote, a confirmed send gated behind that quote's token, and a status check. That means a Claude Desktop or Claude Code session can quote and mail a letter inside the conversation, no custom REST wrapper required. Reaching PostGrid from an agent means building that wrapper yourself first.
- One published all-in price. Every paperplane format has one price with postage, printing and the envelope included, published on the pricing page and returned by the quote before anything is sent. There is no rate card to decode and no per-piece tier to qualify for, which most mail APIs, PostGrid included, cannot say for a single order.
Where PostGrid is ahead
PostGrid has real strengths paperplane does not try to match today, and it would be dishonest to pretend otherwise:
- International mail. PostGrid supports sending mail outside the US, with rules and available services that vary by destination country. paperplane sends to US addresses only — international is not live here.
- Broader piece-type range. PostGrid supports postcards, checks, and campaign-oriented tooling built for sending the same piece to many recipients at once, at real production scale. paperplane sends letters — First-Class, Certified, Certified with electronic Return Receipt, and Priority — and does not yet support postcards, checks, or bulk/campaign sends. If your workflow needs any of those, PostGrid is the tool that has them today.
Side-by-side
| paperplane | PostGrid | |
|---|---|---|
| Account required to send | No, for a single letter | Yes, API key from the first send |
| AI agent integration | Native MCP server (/api/mcp) | REST API only — agent access needs custom integration |
| Piece types | Letters only | Letters, postcards, checks, and more |
| International mail | Not available | Available, varies by country |
| Bulk/campaign sending | Not available — one letter at a time | Available |
| Pricing transparency | One all-in price per piece, published up front | Per-piece rates, typically volume-tiered |
| Starting price | $1.99 First-Class | Varies by piece type and volume tier |
How to choose
If you need to mail internationally, send postcards or checks, or run a mail campaign to a list of recipients, PostGrid is built for that today and paperplane is not — go with PostGrid rather than waiting on us. If what you actually need is to get one important letter into the US mail — a legal notice, a contract, a certified filing — without creating a developer account first, or you are building an AI agent that should be able to mail something on its own without a bespoke integration, paperplane is built specifically for that.
See the full price breakdown on our Certified Mail cost guide, or read how the MCP server works for agent integrations.
Common questions
Does paperplane require an account like PostGrid does?
No. PostGrid is built around API keys and a developer account from the first request. paperplane lets you send a single letter from the website with just a credit card — no account, no API key — and separately offers an API and MCP server for anyone building recurring or programmatic sends. Use whichever entry point matches what you are actually doing.
Can paperplane send postcards, checks, or international mail like PostGrid?
Not today. paperplane sends letters only, to US addresses. PostGrid supports a broader range of piece types (postcards, checks, and more) and international mailing with country-by-country rules. If your use case is a postcard campaign, a check run, or mail leaving the US, PostGrid is the right tool right now — we would rather say that plainly than pretend otherwise.
What does "MCP server" mean and why does it matter here?
MCP (Model Context Protocol) lets an AI agent call a tool directly instead of you writing custom integration code around a REST API. paperplane runs a real MCP server at /api/mcp with three tools — quote_letter, send_letter, get_letter_status — so an agent in Claude Desktop, Claude Code, or another MCP client can price and mail a letter in the same conversation. PostGrid, like most mail APIs, expects a traditional REST integration; an agent can still call it, but someone has to build that bridge first.
Is paperplane cheaper than PostGrid?
It depends on volume and mail class. paperplane publishes flat retail prices — $1.99 First-Class, $12.99 Certified, $14.99 Certified with electronic Return Receipt, $24.99 Priority — all-in, postage and printing included, so the number on the page is the number you pay. PostGrid, like most volume mail APIs, is generally priced around per-piece rates that improve with committed volume; for a single letter or a handful of one-off sends, comparing our flat price against their lowest-tier per-piece rate is the fair comparison, and we would rather you check both than take our word for it.