{"uid":"cap_fW4CWP3HAo3ZueqbeCUWj","slug":"postagent-physical-mail-api-print-mail-letter-via-usps-a6355ee7","name":"PostAgent Physical Mail API – Print & Mail Letter via USPS","description":"Print and mail physical US letters (PDF, HTML, Markdown, DOCX, or image) and postcards via USPS, paid in USDC — with certified/registered proof options and standalone address verification at POST /v1/verify. Integration flow: POST /v1/documents to upload, POST /v1/quotes to lock a fixed USDC price for a recipient, then pay the returned per-quote x402 URL to create and mail the piece. Price is fixed per quote.","url":"https://postagent-api.interpretai.tech/v1/print","method":"POST","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["POST"],"type":"string"},"queryParams":{"type":"object","properties":{"webhookUrl":{"type":"string","description":"Optional HTTPS URL that receives job status webhooks after the letter is created."}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"1.24","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$1.37/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"1.37","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"1.37","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_Vj2MbrJ-2bpV5ErUWJ26p","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"1.37","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Prints and mails a physical US letter (PDF, HTML, Markdown, DOCX, or image) via USPS, paid in USDC using the x402 payment protocol","exampleAgentPrompt":"Mail this attached PDF contract to John Smith at 123 Main St, Austin TX 78701 — print it and send it via USPS, and notify me at https://myapp.com/webhooks/mail when it's been dispatched.","exampleUseCases":[{"title":"Automated contract delivery to clients","prompt":"Send this Word document contract to our client at 456 Oak Avenue, Denver CO 80202 via USPS — print it professionally and let me know when it's in the mail at my webhook endpoint so I can follow up"},{"title":"Physical invoice distribution via postal service","prompt":"Mail these three invoices as printed PDFs to our vendors — first one goes to 789 Elm Street, Chicago IL 60601, second to 321 Pine Road, Seattle WA 98101, and third to 654 Maple Drive, Boston MA 02101 — use USDC to pay and send status updates to my system"},{"title":"Legal notice dispatch with certified proof","prompt":"I need to send this registered legal notice as an HTML document to 987 Birch Lane, Miami FL 33101 with certified mail tracking — pay in USDC and post confirmation to my webhook when it's delivered"}],"resultDescription":"The agent receives confirmation that the letter has been created and queued for USPS mailing, along with a job ID and status. If a webhookUrl was provided, the agent also receives asynchronous status updates (e.g. created, mailed) posted to that URL. The fixed USDC price was locked at the quote stage before this call.","failureModes":["Invalid or unsupported document format — only PDF, HTML, Markdown, DOCX, and image files are accepted","Missing required quote step — the x402 payment URL must be obtained from /v1/quotes before calling /v1/print","Payment failure — insufficient USDC balance or invalid x402 payment header","Invalid US recipient address — non-US or malformed addresses will be rejected","Webhook URL unreachable — optional webhook notifications may silently fail if the provided URL is unavailable","Document upload not completed — /v1/documents must be called first to upload the file before printing"],"whenToPreferThis":"Use this endpoint when an AI agent needs to physically mail a document to a US address via USPS, especially in automated workflows where the user cannot or does not want to visit a post office. Ideal for sending invoices, legal notices, contracts, or personal letters in digital formats (PDF, HTML, Markdown, DOCX, image). Prefer this over email delivery when a physical paper record is required or when the recipient does not have a digital address. The USDC/x402 payment model makes it suitable for crypto-native or agent-driven workflows without traditional billing setup.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T00:30:19.101Z","isFirstParty":false}