# PostalForm Machine Payments API

**Canonical:** https://apis.io/apis/postalform-com/postalform-machine-payments-api/  
**Provider:** PostalForm — https://apis.io/providers/postalform-com/  
**Base URL:** https://postalform.com/api/machine  
**Documentation:** https://postalform.com/developers

PostalForm Machine Payments API is one of 4 APIs that [PostalForm](https://apis.io/providers/postalform-com/) publishes on the [APIs.io](https://apis.io/) network, described by a machine-readable OpenAPI specification. Tagged areas include Physical Mail, x402, Machine Payments, Agents, and Agentic Commerce. The published artifact set on APIs.io includes an OpenAPI specification, API documentation, and an API reference.

Machine-oriented print-and-mail REST API for autonomous agents: validate and quote, then create, pay for and poll document mail orders (PDF, server-rendered letter in text/html/markdown/rtf, workflow form, or CSV bulk campaign), flower letters and MPP-only shipping labels. No API key — every paid create answers HTTP 402 with an x402 PAYMENT-REQUIRED header (USDC on Base, Coinbase CDP facilitator) or MPP WWW-Authenticate: Payment challenges (Tempo, Stripe shared payment token, card), and the retry reuses the same request_id, which the contract treats as a strict idempotency key. 17 operations across 17 paths, OpenAPI 3.1.0 with x-payment-info and x-agent-guidance extensions, served at https://postalform.com/openapi.json.

## Operations (17)

| Method | Path | Summary |
|---|---|---|
| GET | `/api/machine/forms` | List workflow forms available to machine order flows |
| GET | `/api/machine/forms/{slug}/schema` | Get a machine-usable workflow form schema |
| POST | `/api/machine/orders/validate` | Validate an x402 machine order and return a quote |
| POST | `/api/machine/orders` | Create or reuse an x402 machine order |
| GET | `/api/machine/orders/{id}` | Get x402 machine order status |
| POST | `/api/machine/flower-letters/validate` | Validate an x402 flower-letter order and return a Florist One quote |
| POST | `/api/machine/flower-letters` | Create or reuse an x402 flower-letter order |
| GET | `/api/machine/flower-letters/{id}` | Get x402 flower-letter order status |
| POST | `/api/machine/mpp/orders/validate` | Validate an MPP machine order and return a quote |
| POST | `/api/machine/mpp/orders` | Create or reuse an MPP machine order |
| GET | `/api/machine/mpp/orders/{id}` | Get MPP machine order status |
| POST | `/api/machine/mpp/flower-letters/validate` | Validate an MPP flower-letter order and return a Florist One quote |
| POST | `/api/machine/mpp/flower-letters` | Create or reuse an MPP flower-letter order |
| GET | `/api/machine/mpp/flower-letters/{id}` | Get MPP flower-letter order status |
| POST | `/api/machine/mpp/shipping-labels/validate` | Validate an MPP shipping-label request and return live rates |
| POST | `/api/machine/mpp/shipping-labels` | Create, pay for, and download an MPP shipping label |
| GET | `/api/machine/mpp/shipping-labels/{id}` | Get MPP shipping-label payment, fulfillment, and download status |

## Machine-readable artifacts (7)

- **OpenAPI** — https://raw.githubusercontent.com/api-evangelist/postalform-com/refs/heads/main/openapi/postalform-com-machine-payments-openapi.json
- **OpenAPI** — https://postalform.com/openapi.json
- **Documentation** — https://postalform.com/developers
- **APIReference** — https://postalform.com/openapi.json
- **Documentation** — https://postalform.com/agents
- **Overlay** — https://raw.githubusercontent.com/api-evangelist/postalform-com/refs/heads/main/overlays/postalform-com-machine-payments-overlay.yaml
- **APIsJSON** — https://raw.githubusercontent.com/api-evangelist/postalform-com/refs/heads/main/apis.yml

## Other PostalForm APIs (3)

- [PostalForm Projects Public API](https://apis.io/apis/postalform-com/postalform-projects-public-api/)
- [PostalForm MCP Server](https://apis.io/apis/postalform-com/postalform-mcp-server/)
- [PostalForm A2A Agent](https://apis.io/apis/postalform-com/postalform-a2a-agent/)

## Tags

Physical Mail, x402, Machine Payments, Agents, Agentic Commerce

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/postalform-com/postalform-machine-payments-api/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/postalform-com/.