Docs & GitHub

Everything public lives under github.com/Payloadhq. Free projects are MIT-licensed; product repos carry documentation and links to the paid kits.

Free & open source

payload-sample-mcp-server

Free sample MCP server on the official MCP Python SDK demonstrating per-tool-call x402 payments: unpaid callers get machine-readable payment requirements, paying callers get results, free tools stay free. Companion to the MCP Monetization Engine.

MIT Python MCP

mcp-monetization-demo

Runnable demo of the metering mechanic behind the MCP Monetization Engine: per-tool-call metering with a free quota, then machine-readable PAYMENT REQUIRED. Stdlib Python only, hard-capped so it can't replace the paid kit.

MIT Python

n8n-reliability-free-samples

Two production n8n workflows from the n8n Reliability Guard (failure-alert dispatcher, HTTP timeout circuit breaker), import-ready with zero credentials required.

MIT n8n

mcp-manifest-validator

Validate an MCP server.json manifest before you publish: required fields, name format, semver, transport declarations, and the common mistakes registries reject. Zero dependencies.

MIT Python MCP

n8n-workflow-linter

Static lint for exported n8n workflow JSON: missing error handling, HTTP nodes without timeouts or retries, hardcoded secrets, trigger problems, dead nodes. Each finding names the node and the fix.

MIT Python n8n

csv-duplicate-inspector

Inspect a CSV for duplicate risk before a migration: exact-duplicate rows, key-column duplicates, near-duplicates. Streams large files instead of loading them.

MIT Python CSV

mcp-readiness-check

Free GitHub Action: 10 MCP server readiness checks on every pull request — manifest validity, name format, semver, transport, secret heuristics. Use Payloadhq/mcp-readiness-check@v1.

MIT GitHub Action MCP

Product documentation repos

x402-paid-api-starter-kit — docs and checkout link for the Veyline Developer Primer.
mcp-monetization-kit — docs and checkout link for the MCP Monetization Engine.
stableledger — docs and checkout link for StableLedger.

Veyline quickstart

Start free, get an API key, and make your first calls. The free Sandbox tier includes 1,000 operations per month and the full safety foundation.

Start your free sandbox. In the Veyline pricing section, enter your email and click Start Free. Your API key is shown once — copy it immediately; it cannot be recovered later.
Check your account. curl -H "Authorization: Bearer YOUR_KEY" https://payload-rail.fly.dev/v1/veyline/status returns your org, tier, and status. .../v1/veyline/usage shows operations used against your included allocation.
Run a hosted action on your subscription. curl -X POST -H "Authorization: Bearer YOUR_KEY" -H "Content-Type: application/json" -d '{"intent":"purchase","target":"api.example.com/data","max_spend_usdc":"0.05"}' https://payload-rail.fly.dev/v1/callx402/actions/preflight authorizes a preflight check metered to your subscription and returns an invocation id; the action itself executes in your callx402 runtime. List all actions with GET https://payload-rail.fly.dev/v1/callx402/actions.

Every call sends your key as Authorization: Bearer <key>. Keys are product-bound to Veyline. The full machine-readable API reference is in agents.json.

Privacy policies

Public privacy policies for Payload products: github.com/Payloadhq/privacy.

AI Search Readiness Audit privacy policy — the extension is 100% client-side: no account, no server, no analytics, no tracking.

Support

Questions about any product: contact@payloadhq.dev.