Paid implementation plans

Tested plans for agentic businesses.

Inspect the evidence for free. Buy the complete Markdown plan with x402 or MPP.

Plans

1 ready

Sell one existing HTTP route with x402 V2

$0.50 · revised 2026-08-23

Outcome

This plan adds a $0.50 x402 V2 payment gate to one existing FastAPI GET route.

The route accepts Base USDC through the CDP facilitator. Its first 402 challenge includes CDP Bazaar discovery metadata.

The final proof is an HTTP 200 response, a settlement receipt, and a successful Base transaction.

This plan does not contain a code package. It contains commands and code blocks that you apply to your API.

Tested environment

ItemTested value
OSUbuntu 26.04 LTS, x86_64
Python3.14.4
pip25.1.1
cdp-sdk1.47.1
fastapi0.141.1
httpx0.28.1
python-dotenv1.2.3
uvicorn0.52.3
x4022.19.0 with `evm`, `extensions`, and `fastapi` extras
x402 networkeip155:8453` (Base mainnet)
Base USDC0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
CDP facilitator basehttps://api.cdp.coinbase.com/platform/v2/x402
Facilitator supporthttps://api.cdp.coinbase.com/platform/v2/x402/supported
Facilitator verificationhttps://api.cdp.coinbase.com/platform/v2/x402/verify
Facilitator settlementhttps://api.cdp.coinbase.com/platform/v2/x402/settle

Friction sections

  • Friction 1: Pin the environment before you edit the route
  • Friction 2: The receiver does not need a hot key
  • Friction 3: Store the facilitator keys without exposing them
  • Friction 4: FastAPI and x402 use different path-parameter syntax
  • Friction 5: Make sure that the 402 occurs before request validation
  • Friction 6: Read the amount from the V2 header
  • Friction 7: Use a separate buyer with a hard cap
  • Friction 8: Bazaar indexing starts after settlement

23 acceptance checks

View the complete order on BaseScan

Paste into your coding agent

Buy Sell one existing HTTP route with x402 V2 for $0.50.

Use one of these paid GET routes:
- https://krimskrams.xyz/v1/plans/plan-1-sell-one-route-x402-v2 over x402 on Base USDC
- https://krimskrams.xyz/mpp/v1/plans/plan-1-sell-one-route-x402-v2 over MPP on Tempo

JSON catalog slug: plan-1-sell-one-route-x402-v2