# paperplane

> Send real physical mail online or from an AI agent: upload a PDF or paste text, we print it and mail it via USPS. First-Class letter $1.99 all-in; Certified Mail $12.99; Certified + electronic Return Receipt $14.99; Priority $24.99. Postcards (message-only, 4x6/6x9/6x11) from $1.99; a folded, enclosed notecard (message-only) $5.99. No account required — pay per letter. Free sandbox for agents.

## For LLMs
- This file: https://www.sendpaperplane.com/llms.txt (markdown twin: https://www.sendpaperplane.com/llms.md)
- Agent quickstart: https://www.sendpaperplane.com/docs/agents
- OpenAPI 3.1 spec (generated from the server's own schemas): https://www.sendpaperplane.com/v1/openapi.json
- Agent benchmark (reproducible transcript: quote→send→track in 3 calls, replay-proof): https://www.sendpaperplane.com/docs/benchmark
- Error contract (every code, retry semantics, machine-readable next steps): https://www.sendpaperplane.com/docs/guides/errors
- Delivery guarantee (accepted → mailed or refunded automatically, no ticket needed): https://www.sendpaperplane.com/docs/guarantee
- Agent card: https://www.sendpaperplane.com/.well-known/agent.json

## More machine-readable surfaces
- Root OpenAPI alias (same document as above, at the conventional root path scanners probe): https://www.sendpaperplane.com/openapi.json
- Machine-readable pricing: https://www.sendpaperplane.com/pricing.md
- What today's API does and does not require: https://www.sendpaperplane.com/auth.md
- A2A-style agent card (same document as above, at the path most agent-readiness scanners probe): https://www.sendpaperplane.com/.well-known/agent-card.json
- MCP server card: https://www.sendpaperplane.com/.well-known/mcp/server-card.json
- API catalog (RFC 9727 linkset of every machine-readable surface): https://www.sendpaperplane.com/.well-known/api-catalog

## For AI agents
- MCP endpoint (streamable HTTP): https://www.sendpaperplane.com/api/mcp
- Per-client MCP setup, 22 clients (Claude Code, Claude Desktop, Cursor, VS Code/Copilot, Windsurf, Cline, Continue.dev, Gemini CLI, Codex CLI, Amp, GitHub Copilot CLI, Devin CLI, Factory CLI, Grok Build CLI, JetBrains AI Assistant, Junie, Kiro, Mistral Vibe, OpenCode, Visual Studio, Warp, Zed — exact config for each): https://www.sendpaperplane.com/docs/guides/mcp#connect
- Per-agent landing pages, one setup flow each (Claude Code, Cursor, Codex CLI, Gemini CLI, ChatGPT, Text/SMS): https://www.sendpaperplane.com/agents
- Tools: quote_letter (read), get_letter_status (read), send_letter (WRITE — spends money, mails a physical object, not reversible), buy_credits (WRITE — spends a funded wallet's USDC over x402, STAGED — see /guides/agent-payments)
- Postcards (4x6 $1.99, 6x9 $2.99, 6x11 $3.49 — open-face, message-only) and the notecard ($5.99 — folded and enclosed like a greeting card, message-only) are live today, printing + First-Class postage included, no tracking: pass `format` to POST /v1/orders, or to the quote_letter/send_letter MCP tools
- send_letter requires a single-use confirmation_token from quote_letter, bound to the recipient, content, class and price: a send is never the first call, and nothing can change in between
- Sandbox: pass sandbox=true to send_letter (or buy_credits) for a free instant end-to-end test
- Installable agent Skill (SKILL.md, Claude/Codex-compatible): https://www.sendpaperplane.com/skills/paperplane-agent/SKILL.md
- REST: POST https://www.sendpaperplane.com/v1/quotes, POST https://www.sendpaperplane.com/v1/orders, GET https://www.sendpaperplane.com/v1/orders/:id
- CLI: `npx paperplane send letter.pdf --to "..." --sandbox` — see https://www.sendpaperplane.com/cli

## Key pages
- Send a letter, card, or postcard: https://www.sendpaperplane.com/send
- Live no-signup demo (compose → quote → confirm → sandbox send, real API, full JSON shown): https://www.sendpaperplane.com/demo
- Letter templates gallery (security deposit, IRS, notice to vacate, medical bill, HOA fine): https://www.sendpaperplane.com/templates
- Request/upvote the next template: https://www.sendpaperplane.com/templates/request
- Embed a template on any site (one script): https://www.sendpaperplane.com/template-embed.js (see https://www.sendpaperplane.com/templates/embed/{key})
- Live embed demos in host-site context (news / legal / SMB): https://www.sendpaperplane.com/embed-demos/news, https://www.sendpaperplane.com/embed-demos/legal, https://www.sendpaperplane.com/embed-demos/smb
- Pricing: https://www.sendpaperplane.com/#pricing (machine-readable: https://www.sendpaperplane.com/pricing.md)
- Letter credits (prepaid, up to 35% bonus): https://www.sendpaperplane.com/credits
- Guides index (all how-to and explainer articles): https://www.sendpaperplane.com/guides
- Certified mail guide: https://www.sendpaperplane.com/guides/send-certified-mail-online
- Developer & agent docs: https://www.sendpaperplane.com/developers
- Trust Center (security, data handling, uptime): https://www.sendpaperplane.com/trust
- CLI docs: https://www.sendpaperplane.com/cli
- Public documentation site (Mintlify — quickstart, guides, API playground): https://www.sendpaperplane.com/docs
- Track a letter (no login, shareable): https://www.sendpaperplane.com/track/{trackingNumber}
- Embed the send flow on your own site: https://www.sendpaperplane.com/paperplane.js (see /docs/guides/embed)
- Help center: https://www.sendpaperplane.com/help
- Comparisons index: https://www.sendpaperplane.com/compare
- paperplane vs Mailform: https://www.sendpaperplane.com/compare/paperplane-vs-mailform
- paperplane vs Click2Mail: https://www.sendpaperplane.com/compare/paperplane-vs-click2mail
- Content policy: https://www.sendpaperplane.com/policy
- Changelog: https://www.sendpaperplane.com/changelog
- Status: https://www.sendpaperplane.com/status
- Feature requests: https://www.sendpaperplane.com/feature-requests

## Certified Mail explainers
- What is Certified Mail: https://www.sendpaperplane.com/guides/what-is-certified-mail
- Certified Mail cost: https://www.sendpaperplane.com/guides/certified-mail-cost
- Certified Mail tracking: https://www.sendpaperplane.com/guides/certified-mail-tracking
- Certified vs. Registered Mail: https://www.sendpaperplane.com/compare/certified-mail-vs-registered-mail
- Certified vs. Priority Mail: https://www.sendpaperplane.com/compare/certified-mail-vs-priority-mail
- Online certified-mail services compared (label services vs print-and-mail, honest prices): https://www.sendpaperplane.com/compare/certified-mail-services
- USPS Certificate of Mailing explained: https://www.sendpaperplane.com/guides/certificate-of-mailing
- What counts as proof of mailing: https://www.sendpaperplane.com/guides/proof-of-mailing
- How to send certified mail (post office or online): https://www.sendpaperplane.com/guides/how-to-send-certified-mail
- Legal mailing services for attorneys and pro se filers: https://www.sendpaperplane.com/use-cases/legal-mailing-services
- Certified mail sample/letter example: https://www.sendpaperplane.com/guides/certified-mail-sample
- Address verification, how every order is validated before printing: https://www.sendpaperplane.com/guides/address-verification
- Direct mail API: the actual POST /v1/orders shape, pricing, and webhook automation: https://www.sendpaperplane.com/direct-mail-api
- paperplane vs. Lob comparison: https://www.sendpaperplane.com/compare/paperplane-vs-lob
- paperplane vs. PostGrid comparison: https://www.sendpaperplane.com/compare/paperplane-vs-postgrid
- Mailing client/tenant lists via spreadsheet upload: https://www.sendpaperplane.com/use-cases/agencies-and-consultants
- Proof of service vs. proof of mailing: https://www.sendpaperplane.com/guides/proof-of-service
- Mail merge via API (spreadsheet upload, one letter per row): https://www.sendpaperplane.com/mail-merge-api
- Small claims court demand letters: https://www.sendpaperplane.com/use-cases/small-claims-court-mail
- HOA violation, fine, and assessment notice mailing: https://www.sendpaperplane.com/use-cases/hoa-notice-mailing
- Nonprofit donor thank-you and tax-receipt letters: https://www.sendpaperplane.com/use-cases/nonprofit-donor-mailing
- What is a mailing list, and how to send to one without mail merge: https://www.sendpaperplane.com/guides/what-is-a-mailing-list
- How long does mail take to arrive (delivery times by class): https://www.sendpaperplane.com/guides/how-long-does-mail-take
- USPS mail forwarding, explained: https://www.sendpaperplane.com/guides/usps-mail-forwarding
- Return to sender / refused / unclaimed mail, legal effect: https://www.sendpaperplane.com/guides/return-to-sender-mail
- Missing mail: how to file a USPS claim: https://www.sendpaperplane.com/guides/usps-missing-mail-claim
- First-Class vs. Priority vs. Priority Mail Express: https://www.sendpaperplane.com/compare/first-class-vs-priority-vs-priority-express
- Mail theft: what to do: https://www.sendpaperplane.com/guides/mail-theft
- What happens to a deceased person's mail: https://www.sendpaperplane.com/guides/deceased-person-mail
- Mail insurance explained: https://www.sendpaperplane.com/guides/mail-insurance
- International mail & Global Forever stamps: https://www.sendpaperplane.com/guides/international-mail-forever-stamps
- USPS Hold Mail, explained: https://www.sendpaperplane.com/guides/usps-hold-mail
- Business Reply Mail, explained: https://www.sendpaperplane.com/guides/business-reply-mail
- Undeliverable & dead mail: https://www.sendpaperplane.com/guides/undeliverable-mail
- PO Box rental basics: https://www.sendpaperplane.com/guides/po-box-rental
- USPS Informed Delivery, explained: https://www.sendpaperplane.com/guides/usps-informed-delivery
- Media Mail rates & restrictions: https://www.sendpaperplane.com/guides/media-mail

## Letter templates (template+send; the same content as /templates and /templates/[slug])
- Security deposit demand letter: https://www.sendpaperplane.com/templates/security-deposit-demand-letter
- IRS response letter: https://www.sendpaperplane.com/templates/irs-response-letter
- Notice to vacate (tenant to landlord): https://www.sendpaperplane.com/templates/notice-to-vacate-letter
- Medical bill dispute letter: https://www.sendpaperplane.com/templates/medical-bill-dispute-letter
- HOA fine dispute letter: https://www.sendpaperplane.com/templates/hoa-fine-dispute-letter
- Cease and desist letter: https://www.sendpaperplane.com/templates/cease-and-desist-letter
- Resignation letter: https://www.sendpaperplane.com/templates/resignation-letter
- Debt validation letter: https://www.sendpaperplane.com/templates/debt-validation-letter
- Lease termination letter: https://www.sendpaperplane.com/templates/lease-termination-letter
- Demand letter (general): https://www.sendpaperplane.com/templates/demand-letter
- Late rent notice: https://www.sendpaperplane.com/templates/late-rent-notice
- Eviction notice (landlord to tenant): https://www.sendpaperplane.com/templates/eviction-notice-letter
- Collection letter (business, first notice): https://www.sendpaperplane.com/templates/collection-letter
- Letter of intent to sue: https://www.sendpaperplane.com/templates/letter-of-intent-to-sue
- Cure or quit notice (landlord to tenant): https://www.sendpaperplane.com/templates/cure-or-quit-notice
- Insurance appeal letter: https://www.sendpaperplane.com/templates/insurance-appeal-letter
- Unemployment appeal letter: https://www.sendpaperplane.com/templates/unemployment-appeal-letter
- Rent increase notice (landlord to tenant): https://www.sendpaperplane.com/templates/rent-increase-notice
- Lease renewal letter: https://www.sendpaperplane.com/templates/lease-renewal-letter
- Landlord entry notice (notice of intent to enter): https://www.sendpaperplane.com/templates/landlord-entry-notice
- Habitability / mold complaint letter: https://www.sendpaperplane.com/templates/habitability-complaint-letter
- Repair request letter (tenant to landlord): https://www.sendpaperplane.com/templates/repair-request-letter
- Notice of lease violation (non-rent, non-eviction): https://www.sendpaperplane.com/templates/lease-violation-notice
- Tenant notice of intent to move out (lease-end): https://www.sendpaperplane.com/templates/tenant-notice-of-intent-to-move-out
- Co-signer / guarantor notice of default: https://www.sendpaperplane.com/templates/cosigner-default-notice
- Move-out / final inspection request letter: https://www.sendpaperplane.com/templates/move-out-inspection-request
- Sublease / assignment request letter: https://www.sendpaperplane.com/templates/sublease-request-letter
- Roommate removal / addition notice: https://www.sendpaperplane.com/templates/roommate-change-notice
- Landlord's response to repair request letter: https://www.sendpaperplane.com/templates/landlord-repair-response-letter
- Credit report dispute letter: https://www.sendpaperplane.com/templates/credit-report-dispute-letter
- Gym / subscription / timeshare cancellation letter (certified mail required): https://www.sendpaperplane.com/templates/certified-mail-cancellation-letter
- Change of address notice to court, IRS, or licensing board: https://www.sendpaperplane.com/templates/change-of-address-legal-notice
- Bank / credit card chargeback dispute letter: https://www.sendpaperplane.com/templates/chargeback-dispute-letter
- Wage theft / unpaid final paycheck demand letter: https://www.sendpaperplane.com/templates/wage-theft-demand-letter
- Security deposit itemization request: https://www.sendpaperplane.com/templates/security-deposit-itemization-request
- Contractor / home repair demand letter (incomplete work): https://www.sendpaperplane.com/templates/contractor-demand-letter
- Insurance claim denial follow-up / reconsideration letter: https://www.sendpaperplane.com/templates/insurance-reconsideration-letter
- Legal name change notification letter: https://www.sendpaperplane.com/templates/legal-name-change-notification
- Warranty claim letter: https://www.sendpaperplane.com/templates/warranty-claim-letter
- Power of attorney notification letter: https://www.sendpaperplane.com/templates/power-of-attorney-notification
- Executor / estate notification letter to creditors: https://www.sendpaperplane.com/templates/estate-creditor-notification
- Formal overdue invoice notice (B2B): https://www.sendpaperplane.com/templates/overdue-invoice-notice
- Business change-of-address notice to clients/vendors: https://www.sendpaperplane.com/templates/business-change-of-address-notice
- Board resolution mailing (small LLCs and corporations): https://www.sendpaperplane.com/templates/board-resolution-mailing
- HOA notice of covenant violation: https://www.sendpaperplane.com/templates/hoa-violation-notice
- Vendor payment demand letter (refund/credit owed): https://www.sendpaperplane.com/templates/vendor-payment-demand-letter
- Insurance claim follow-up letter (stalled or unanswered claim): https://www.sendpaperplane.com/templates/insurance-claim-follow-up-letter
- Subcontractor preliminary lien notice: https://www.sendpaperplane.com/templates/preliminary-lien-notice-letter
- Employee termination letter: https://www.sendpaperplane.com/templates/employee-termination-letter
- Tenant estoppel certificate request: https://www.sendpaperplane.com/templates/tenant-estoppel-certificate-letter
- Notice of Intent to Lien (contractor to property owner): https://www.sendpaperplane.com/templates/mechanics-lien-notice
- Notice of breach of contract (with cure period): https://www.sendpaperplane.com/templates/breach-of-contract-notice

## Sending mail without a template
- Mail a letter online (paste text or upload a PDF, no template needed): https://www.sendpaperplane.com/guides/mail-a-letter-online
- How to send a letter without a printer: https://www.sendpaperplane.com/guides/send-a-letter-without-a-printer

## Tax, contracts & professional mailing
- Mailing a W-9 or 1099 to a contractor or vendor: https://www.sendpaperplane.com/guides/mailing-w9-1099
- Notarized document mailing, explained: https://www.sendpaperplane.com/guides/notarized-mail
- Mailing a contract for physical signature: https://www.sendpaperplane.com/guides/mailing-a-contract-for-signature

## Developer / agent-native guides
- How AI agents can mail physical letters via MCP: https://www.sendpaperplane.com/guides/ai-agents-mcp-mail
- Automating compliance mail from your CRM or support tool via API: https://www.sendpaperplane.com/guides/automate-compliance-mail-api
- What happens after you hit send: a delivery timeline for businesses: https://www.sendpaperplane.com/guides/business-mail-delivery-timeline
- Use paperplane in Grok (custom MCP connector, user-side setup): https://www.sendpaperplane.com/guides/use-paperplane-in-grok
- Use paperplane in Lindy (MCP server, user-side setup): https://www.sendpaperplane.com/guides/use-paperplane-in-lindy
- Use paperplane in Gumloop (custom MCP connector, user-side setup): https://www.sendpaperplane.com/guides/use-paperplane-in-gumloop
- Use paperplane in Dust (remote MCP server, user-side setup): https://www.sendpaperplane.com/guides/use-paperplane-in-dust
- Use paperplane in n8n (real community node, n8n-nodes-paperplane): https://www.sendpaperplane.com/guides/use-paperplane-in-n8n
- Use paperplane in Pipedream (real component, ready to run ahead of its public app listing): https://www.sendpaperplane.com/guides/use-paperplane-in-pipedream

## More guides
- Use paperplane in Microsoft Copilot Studio: https://www.sendpaperplane.com/guides/use-paperplane-in-copilot-studio
- Send mail from LangGraph, the Vercel AI SDK, or OpenClaw: https://www.sendpaperplane.com/guides/agent-code-recipes-langgraph-vercel-openclaw

## Use-case guides (when to use which mail class, what proof matters)
- Index: https://www.sendpaperplane.com/use-cases
- Send a certified demand letter online: https://www.sendpaperplane.com/use-cases/certified-demand-letter
- Mail landlord-tenant notices online: https://www.sendpaperplane.com/use-cases/landlord-tenant-notices
- Send real estate correspondence by mail: https://www.sendpaperplane.com/use-cases/real-estate-letters
- Mail an insurance claim or appeal letter: https://www.sendpaperplane.com/use-cases/insurance-claim-letters
- Mail a letter to the IRS or a government agency: https://www.sendpaperplane.com/use-cases/irs-and-government-letters
- Send a letter to your HOA (or from one): https://www.sendpaperplane.com/use-cases/hoa-letters
- Cancel a gym or subscription by mail: https://www.sendpaperplane.com/use-cases/cancel-subscription-by-mail
- Mail invoices and collection letters: https://www.sendpaperplane.com/use-cases/small-business-invoices
- Send a thank-you letter by real mail: https://www.sendpaperplane.com/use-cases/thank-you-letters
- Write to your representative by real mail: https://www.sendpaperplane.com/use-cases/letters-to-elected-officials
- Send personal letters and pen pal mail online: https://www.sendpaperplane.com/use-cases/pen-pals-and-personal-letters
- Certified legal mail for solo and small firms: https://www.sendpaperplane.com/use-cases/legal-correspondence-small-firms
- Mail an eviction or notice-to-quit letter: https://www.sendpaperplane.com/use-cases/eviction-and-notice-to-quit
- Mail a real estate disclosure statement: https://www.sendpaperplane.com/use-cases/real-estate-disclosure-mailing
- Send a customer apology or service-recovery letter: https://www.sendpaperplane.com/use-cases/customer-apology-letters
- Send a sympathy or condolence card by mail: https://www.sendpaperplane.com/use-cases/sympathy-and-condolence-cards
- Send appointment and event reminder postcards: https://www.sendpaperplane.com/use-cases/appointment-reminder-postcards
- Send outreach postcards from an AI agent or CRM: https://www.sendpaperplane.com/use-cases/agent-triggered-postcard-outreach
- Send handwritten-style marketing postcards for small business: https://www.sendpaperplane.com/use-cases/handwritten-postcard-marketing
- Send a real letter or postcard by texting it: https://www.sendpaperplane.com/use-cases/send-mail-by-text

## Integration guides (honest: REST + MCP work today, native apps are planned)
- Index (surfaces: REST /v1, MCP /api/mcp, CLI, SDKs — native apps for Zapier/n8n/Make): https://www.sendpaperplane.com/integrations
- Native surfaces (web composer, email-to-send, text/SMS, MCP/agent access — not third-party tools): https://www.sendpaperplane.com/integrations/native
- Send by text/SMS (natural language or a TO: block/Contact card, quote-then-confirm): https://www.sendpaperplane.com/docs/guides/imessage-to-send
- Send mail from ChatGPT: https://www.sendpaperplane.com/integrations/chatgpt
- Send mail from Claude (MCP): https://www.sendpaperplane.com/integrations/claude-mcp
- Send mail from Zapier: https://www.sendpaperplane.com/integrations/zapier
- Send mail from Make: https://www.sendpaperplane.com/integrations/make
- Send mail from n8n: https://www.sendpaperplane.com/integrations/n8n
- Send mail from Google Drive: https://www.sendpaperplane.com/integrations/google-drive
- Send mail from Notion: https://www.sendpaperplane.com/integrations/notion
- Send mail from Cursor: https://www.sendpaperplane.com/integrations/cursor
- Send mail from Dropbox: https://www.sendpaperplane.com/integrations/dropbox
- Send mail from Google Sheets: https://www.sendpaperplane.com/integrations/google-sheets
- Send mail from HubSpot: https://www.sendpaperplane.com/integrations/hubspot
- Send mail from a Slack message: https://www.sendpaperplane.com/integrations/slack
- Send mail from a Stripe event: https://www.sendpaperplane.com/integrations/stripe
- Send mail from a Google Forms submission: https://www.sendpaperplane.com/integrations/google-forms
- Send mail from Airtable: https://www.sendpaperplane.com/integrations/airtable
- Mail a letter from any webhook: https://www.sendpaperplane.com/integrations/webhook
- Google Sheets bulk mail merge — one letter per row: https://www.sendpaperplane.com/integrations/google-sheets/bulk-mail-merge
- Notion database row to certified mail run: https://www.sendpaperplane.com/integrations/notion/certified-mail
- Google Drive file to mailed PDF, automatically: https://www.sendpaperplane.com/integrations/google-drive/mailed-pdf
- HubSpot new contact to welcome letter: https://www.sendpaperplane.com/integrations/hubspot/welcome-letter
- Slack message to one-off certified letter: https://www.sendpaperplane.com/integrations/slack/certified-letter
- Stripe invoice to mailed paper invoice: https://www.sendpaperplane.com/integrations/stripe/mailed-invoice
- Google Forms submission to mailed confirmation: https://www.sendpaperplane.com/integrations/google-forms/mailed-confirmation
- Airtable record to certified legal notice: https://www.sendpaperplane.com/integrations/airtable/legal-notice
- Dropbox shared PDF to mailed letter: https://www.sendpaperplane.com/integrations/dropbox/mailed-letter
- Generic webhook to mailed letter: https://www.sendpaperplane.com/integrations/webhook/mailed-letter

## Free calculators (client-side, no signup — the numbers come from the same pricing and delivery code that runs real orders)
- Index: https://www.sendpaperplane.com/tools
- Certified Mail cost calculator: https://www.sendpaperplane.com/tools/certified-mail-cost-calculator
- USPS mail delivery date estimator: https://www.sendpaperplane.com/tools/delivery-date-estimator
- Compare USPS delivery windows by mail class: https://www.sendpaperplane.com/tools/delivery-window-comparison
- Certified Mail or Registered Mail — which do you need?: https://www.sendpaperplane.com/tools/certified-vs-registered-mail-chooser

## Glossary (one postal term, one short definition per page)
- Index: https://www.sendpaperplane.com/glossary
- Certified Mail: https://www.sendpaperplane.com/glossary/certified-mail
- Return receipt: https://www.sendpaperplane.com/glossary/return-receipt
- Electronic Return Receipt: https://www.sendpaperplane.com/glossary/electronic-return-receipt
- PS Form 3800: https://www.sendpaperplane.com/glossary/ps-form-3800
- PS Form 3811: https://www.sendpaperplane.com/glossary/ps-form-3811
- Restricted Delivery: https://www.sendpaperplane.com/glossary/restricted-delivery
- Signature Confirmation: https://www.sendpaperplane.com/glossary/signature-confirmation
- Certificate of Mailing: https://www.sendpaperplane.com/glossary/certificate-of-mailing
- Proof of mailing: https://www.sendpaperplane.com/glossary/proof-of-mailing
- Proof of service: https://www.sendpaperplane.com/glossary/proof-of-service
- Registered Mail: https://www.sendpaperplane.com/glossary/registered-mail
- First-Class Mail: https://www.sendpaperplane.com/glossary/first-class-mail
- Priority Mail: https://www.sendpaperplane.com/glossary/priority-mail
- Priority Mail Express: https://www.sendpaperplane.com/glossary/priority-mail-express
- Media Mail: https://www.sendpaperplane.com/glossary/media-mail
- USPS Marketing Mail: https://www.sendpaperplane.com/glossary/usps-marketing-mail
- Every Door Direct Mail: https://www.sendpaperplane.com/glossary/every-door-direct-mail
- Business Reply Mail: https://www.sendpaperplane.com/glossary/business-reply-mail
- Forever stamp: https://www.sendpaperplane.com/glossary/forever-stamp
- Permit imprint: https://www.sendpaperplane.com/glossary/permit-imprint
- Intelligent Mail barcode: https://www.sendpaperplane.com/glossary/intelligent-mail-barcode
- Postcard: https://www.sendpaperplane.com/glossary/postcard
- Notecard: https://www.sendpaperplane.com/glossary/notecard
- Ancillary service endorsement: https://www.sendpaperplane.com/glossary/ancillary-service-endorsement
- Return to sender: https://www.sendpaperplane.com/glossary/return-to-sender
- Undeliverable as addressed: https://www.sendpaperplane.com/glossary/undeliverable-as-addressed
- Mail Recovery Center: https://www.sendpaperplane.com/glossary/mail-recovery-center
- Change of address: https://www.sendpaperplane.com/glossary/change-of-address
- Informed Delivery: https://www.sendpaperplane.com/glossary/informed-delivery
- CASS certification: https://www.sendpaperplane.com/glossary/cass-certification
- NCOALink: https://www.sendpaperplane.com/glossary/ncoalink
- Delivery Point Validation: https://www.sendpaperplane.com/glossary/delivery-point-validation
- Address standardization: https://www.sendpaperplane.com/glossary/address-standardization
- Mail merge: https://www.sendpaperplane.com/glossary/mail-merge
- Variable data printing: https://www.sendpaperplane.com/glossary/variable-data-printing
- Print-and-mail API: https://www.sendpaperplane.com/glossary/print-and-mail-api
- Direct mail: https://www.sendpaperplane.com/glossary/direct-mail
- Service standard: https://www.sendpaperplane.com/glossary/service-standard
- Adult Signature Required: https://www.sendpaperplane.com/glossary/adult-signature-required
- Insured Mail: https://www.sendpaperplane.com/glossary/insured-mail
- Delivery Confirmation: https://www.sendpaperplane.com/glossary/delivery-confirmation
- Bound Printed Matter: https://www.sendpaperplane.com/glossary/bound-printed-matter
- Library Mail: https://www.sendpaperplane.com/glossary/library-mail
- Parcel Select: https://www.sendpaperplane.com/glossary/parcel-select
- First-Class Package Service: https://www.sendpaperplane.com/glossary/first-class-package-service
- First-Class Mail International: https://www.sendpaperplane.com/glossary/first-class-mail-international
- General Delivery: https://www.sendpaperplane.com/glossary/general-delivery
- Nixie: https://www.sendpaperplane.com/glossary/nixie
- Missent mail: https://www.sendpaperplane.com/glossary/missent-mail
- Refused mail: https://www.sendpaperplane.com/glossary/refused-mail
- Notice Left (PS Form 3849): https://www.sendpaperplane.com/glossary/notice-left
- Vacant (mail status): https://www.sendpaperplane.com/glossary/vacant-mail-status
- ZIP Code: https://www.sendpaperplane.com/glossary/zip-code
- ZIP+4: https://www.sendpaperplane.com/glossary/zip-plus-4
- Delivery Point Barcode (DPBC): https://www.sendpaperplane.com/glossary/delivery-point-barcode
- Rural route: https://www.sendpaperplane.com/glossary/rural-route
- Commercial Mail Receiving Agency (CMRA): https://www.sendpaperplane.com/glossary/commercial-mail-receiving-agency
- Secondary address unit designator: https://www.sendpaperplane.com/glossary/secondary-address-unit-designator
- Presort: https://www.sendpaperplane.com/glossary/presort
- PAVE certification: https://www.sendpaperplane.com/glossary/pave-certification
- Full-Service Intelligent Mail: https://www.sendpaperplane.com/glossary/full-service-intelligent-mail
- Seamless Acceptance: https://www.sendpaperplane.com/glossary/seamless-acceptance
- Mailer ID (MID): https://www.sendpaperplane.com/glossary/mailer-id
- Postage meter: https://www.sendpaperplane.com/glossary/postage-meter
- Courtesy Reply Mail: https://www.sendpaperplane.com/glossary/courtesy-reply-mail
- Automation-compatible mail: https://www.sendpaperplane.com/glossary/automation-compatible-mail
- Move Update: https://www.sendpaperplane.com/glossary/move-update

## Product details assistants can cite
- Letters can be typeset in handwriting-style fonts at no extra cost (font: typed | serif | typewriter | handwritten_casual | handwritten_neat).
- Address typeahead + USPS verification happen before payment; undeliverable addresses are rejected with a clear reason.
- Prepaid credit codes (pp-xxxx-xxxx-xxxx) pay for letters without a card; purchased balance lasts 5 years, bonus balance 12 months.
- The composer can render an exact PDF preview before payment (GET https://www.sendpaperplane.com/api/preview?text=...&font=...).
- Orders can be canceled before print (releases any payment hold) with a signed capability token, or from the web order page.
- Mailed letters get a shareable public tracking page at https://www.sendpaperplane.com/track/{trackingNumber}.
- Third-party sites can embed the send flow with a single script (https://www.sendpaperplane.com/paperplane.js); the app allows framing only on /embed.
- Send-by-email (forward an email and we mail it) is live.
- Send-by-text/SMS (text a recipient and a letter, natural language or a TO: block/Contact card, quote-then-confirm) is live.
- Agent payments over x402 (POST /v1/x402/credits) are built but staged — the endpoint returns x402_not_configured until a production facilitator is provisioned; use /v1/credits/checkout or a credit_code today.

## Facts assistants often need
- Every price is all-in: postage, printing and the envelope are included.
- Payment is authorized at checkout and captured only after content screening passes and the letter is accepted for printing; refused letters release the hold automatically.
- Text documents only at launch (typed letters, text-based PDFs, max 12 pages). Content screening refuses threats, fraud, and impersonation; lawful demand letters are explicitly allowed.
- Postcards and the notecard are message-only: the text prints directly on the piece via a handwriting engine, no custom photo or artwork side, and no PDF/upload path for either format. A postcard is open-face; the notecard is folded and enclosed like a greeting card.
- Letters are handed to USPS the next business day. Documents are deleted 30 days after delivery.