inflow-node

Official Node.js SDKs for the InFlow payments platform.

Accounts & environments

Register a Seller account and create an API key in the InFlow dashboard, then pass environment to the SDK. That's the only configuration you need — the SDK resolves the right endpoint internally (don't set baseUrl).

For network egress allowlisting only: the SDK makes its outbound API calls to https://sandbox.inflowpay.ai (sandbox) and https://api.inflowpay.ai (production). You never set these yourself.

What's here

This monorepo houses InFlow's open-source Node.js packages, organized by product. Every package, example, and product doc folder uses a product prefix (x402-, …) so multiple products can coexist without ambiguity.

Packages

All packages publish under the @inflowpayai scope on npm and depend on @x402/core@^2.12.0 as a peer.

Package	npm	Role
@inflowpayai/x402		Core types + HTTP client
@inflowpayai/x402-seller		Facilitator client + seller client + inflowAccepts helper
@inflowpayai/x402-buyer		InflowClient — foundation x402Client subclass for buyers

The MPP packages publish under the same scope but declare mppx@^0.6.28 as their peer instead of @x402/core:

Package	npm	Role
@inflowpayai/mpp		Core: MPP Method definitions, wire types, codec, HTTP client
@inflowpayai/mpp-seller		Method.toServer + InFlow redeem/settle driver — accepting MPP
@inflowpayai/mpp-buyer		Method.toClient + InFlow buyer-endpoint driver — paying via MPP

# Seller accepting MPP payments
pnpm add @inflowpayai/mpp-seller mppx

# Buyer paying via MPP
pnpm add @inflowpayai/mpp-buyer mppx

See the MPP product docs for the seller/buyer integration shape.

Sellers integrate via the foundation V2 middleware (paymentMiddlewareFromConfig from @x402/express, @x402/hono, @x402/fastify, or @x402/next) and pass InFlow's facilitator client into its facilitatorClients array. See the x402 quickstart for the integration shape.

Common installs:

# Seller in Express (foundation middleware + InFlow facilitator)
pnpm add @inflowpayai/x402-seller @x402/express @x402/core express

# Seller in Fastify
pnpm add @inflowpayai/x402-seller @x402/fastify @x402/core fastify

# Seller in Next 16 App Router
pnpm add @inflowpayai/x402-seller @x402/next @x402/core next

# Buyer (InFlow-signed paths only)
pnpm add @inflowpayai/x402-buyer @x402/core

# Buyer composing InFlow with foundation EVM and/or SVM signing
pnpm add @inflowpayai/x402-buyer @x402/core @x402/evm @x402/svm

See the x402 product docs for quickstarts.

Examples

Runnable end-to-end examples live in examples/. Start a seller, then run a buyer against it.

x402:

• x402-seller-express — Express server with three protected routes.
• x402-seller-hono — same shape on Hono via @hono/node-server.
• x402-seller-fastify — same shape on Fastify; @x402/fastify mutates the Fastify instance in place rather than returning middleware.
• x402-seller-next — Next 16 App Router; proxy.ts carries the InFlow wiring and Route Handlers stay x402-free.
• x402-buyer-fetch — paying a protected endpoint with @inflowpayai/x402-buyer + native fetch.
• x402-buyer-axios — paying a protected endpoint with @inflowpayai/x402-buyer + axios.
• x402-buyer-x402-evm — foundation-only EVM buyer (no @inflowpayai/* imports) paying an InFlow seller.
• x402-buyer-x402-svm — foundation-only SVM buyer paying an InFlow seller; same idea on Solana devnet.
• x402-facilitator — InFlow facilitator as a foundation drop-in: vanilla @x402/express seller + foundation-only EVM buyer, with no INFLOW_API_KEY (uses createUnauthenticatedInflowFacilitator).

MPP:

• mpp-aep-seller-express — Express server applying AEP API-key authentication before MPP payment enforcement on the same protected routes.
• mpp-seller-express — Express server accepting MPP payments via mppx's Express adapter + InFlow's inflow seller method, plus a multi-currency /api/checkout route via inflowChargesNodeListener.
• mpp-seller-hono — same shape on Hono via mppx/hono and @hono/node-server; the multi-currency /api/checkout route uses inflowCharges on the core mppx/server instance.
• mpp-buyer-fetch — paying via MPP through a transparently polyfilled global fetch.
• mpp-buyer-manual — paying via MPP through the explicit, non-polyfill mppx.fetch.

Supported runtimes

Node 22 LTS or newer at runtime; the packages ship engines.node: >=22.0.0. CI exercises Node 22 (maintenance LTS until April 2027) and Node 24 (active LTS, April 2028 EOL). Node 20 went EOL on 2026-04-30 and is no longer supported.

Monorepo

For a tour of the monorepo itself — tooling, contributing, publishing — see docs/monorepo:

• contributing — workflow, branch model, commit conventions.
• tooling — pnpm, Turborepo, tsup, Vitest, MSW, ESLint, Prettier.
• publishing — Changesets flow and npm provenance.
• documentation — TSDoc, README, and docs/ style guide.

Security

See SECURITY.md for disclosure. Examples under examples/ are illustrative and out of scope.

License

MIT.