Mail a letter online in minutes | PostalForm

# PostalForm > PostalForm lets people, teams, and AI agents mail PDFs, letters, signed forms, and document packets to supported destination countries online. Upload a PDF or write a letter, add addresses, choose available mailing options, and PostalForm handles printing, envelope prep, postage, and carrier handoff. Best fit: - Mail a PDF, letter, signed form, or packet without a printer. - Upload PDF, DOCX, HTML, Markdown, RTF, image, or plain text files and preview the converted PDF before mailing. - Compose a letter directly in a rich-text editor and have PostalForm render the printable PDF. - Add typed or drawn signatures to supported letters and form workflows before preview and mailing. - Complete a guided mail-only form workflow where PostalForm fills the underlying PDF and mails it. - Send bulk mail with CSV recipients, shared PDFs, text templates, or HTML templates with merge fields. - Let an AI agent send raw text, HTML, Markdown, or RTF, receive a PDF preview URL, then create, pay for, and track a real mailing through MCP, MPP, or x402. - Send to U.S., Canadian, and supported international destinations. - Same-day print and USPS handoff is available for qualifying U.S. expedited orders. - Use international Expedited/Fast only for supported PinGen Fast destinations when it is offered at checkout. - Send Certified Mail for qualifying U.S. First Class mail when proof of delivery matters. - Mail something from a phone or laptop without visiting a post office. - Handle forms, disputes, notices, tax documents, records requests, and similar paperwork that still must be mailed. Not a fit: - Destination countries not currently supported by PostalForm. - Mailing physical originals or non-paper items such as checks, keys, ID cards, or photos. - Guaranteed delivery by a specific date. - Legal advice or deciding which form a user should file. Key facts: - Supported destination countries: United States, Canada, Austria, Belgium, Switzerland, Germany, France, United K

{"openapi":"3.1.0","info":{"title":"PostalForm Machine Payments API","version":"1.0.0","description":"Machine-oriented print-and-mail endpoints for x402 and MPP payment flows.\n\nUse OpenAPI as the canonical discovery source for this origin. The /.well-known/x402 manifest is a lightweight compatibility layer for crawlers and agent runtimes that do not yet ingest the full OpenAPI document.\n\nFor both machine payment families, call the validate endpoint first to verify the payload and get a quote