Monapi

• Name: Monapi
• URL: https://monapi.dev/
• Category: x402 seller middleware / API paywall wrapper
• Tags: ethereum-ecosystem
• Summary: Monapi is seller-side x402 paywall glue. It prices routes, wraps MCP tools, and hides most of the 402 loop. Useful middleware, not a rail.
• What it does:
  • Wraps Express routes with a monapi() middleware so protected endpoints return 402 Payment Required until the caller pays in USDC through x402-compatible flows
  • Wraps Next.js handlers with withMonapi() and supports multi-route protection with monapiProxy()
  • Wraps MCP tool handlers with monapiMcp() so AI-agent tools can be sold on a pay-per-call basis rather than only via subscriptions or API keys
  • Supports either one global price or per-route pricing maps, plus optional payment callbacks for post-payment logging or workflow hooks
  • Supports Base, Arbitrum, and Polygon plus testnets, with USDC as the documented payment token in the current release
  • Ships an npx monapi init wizard that detects the framework, helps configure a wallet, and generates starter configuration and code
• Key claims:
  • The point is to make x402 paywalling feel like framework middleware instead of a protocol-integration project.
  • Express, Next.js, and MCP support are why the note earns space. This is more than a tiny one-route helper.
  • The real control sits in route pricing, facilitator choice, wallet destination, and payment callbacks. Seller-side operating glue, not a new rail.
  • The roadmap still reads ahead of the shipped product. The live thing is a route-paywall wrapper.
• Whitepaper: No canonical standalone Monapi whitepaper or litepaper surfaced in this pass. The clearest current source of truth was the official site and canonical GitHub repository/README; see ../whitepapers/monapi-primary-sources-2026-05-03.md.
• Sources:
  • https://monapi.dev/
  • https://github.com/DenisTheM/monapi
  • https://raw.githubusercontent.com/DenisTheM/monapi/main/README.md

Internal linkages

• Best upward reads: x402 and 402-index.

Control surface

• The leverage sits in route-pricing defaults, accepted network and token choices, facilitator selection, wallet destination, and how payment callbacks get wired into the seller backend.

• Useful seller-side glue. Still wrapper middleware above stronger paid-request standards.

• Last reviewed: 2026-06-18 UTC