Why X402Flex
x402 V2 standardizes how payments are requested and carried over HTTP. X402Flex standardizes how those payments are authorized, rate‑limited, and settled on EVM.
x402 V2 vs X402Flex (honest framing)
x402 V2 is the HTTP payment standard. It focuses on API‑native payment negotiation, discovery, and cross‑network compatibility. X402Flex is the on‑chain settlement and authorization engine that makes those HTTP payments verifiable and safe across multiple funding rails.
x402 V2 pushes toward wallet‑based access, automatic discovery, dynamic pay‑to routing, CAIP‑based network identifiers, and modular SDKs. That makes the facilitator + on‑chain settlement layer more critical than ever. X402Flex is the EVM layer purpose‑built for that role.
References: x402 V2 launch, Coinbase x402 docs.
Why X402Flex is better (in the ways developers and partners care about)
1) Deterministic on‑chain settlement (one canonical truth)
Every payment scheme routes through a single settlement point (X402FlexRegistry) and emits one canonical PaymentSettledV2 event. Wallets, merchants, and indexers all reconcile against the same on‑chain record, regardless of how the payer funded the transaction.
2) Multiple real‑world funding rails
X402Flex supports Permit2, ERC‑2612, EIP‑3009, and push deposits. That means developers can accept what users already have instead of betting on a single token standard or wallet capability.
3) Session‑based identity + spending guardrails
x402 V2 is moving toward wallet‑based access and reusable sessions. X402Flex already enforces session caps, daily caps, rate limits, spend nonces, and claimable sessions on‑chain—giving merchants and platforms safety controls that HTTP alone can’t enforce.
4) Cryptographic intent binding (no “trust me”)
X402Flex binds merchant, token, amount, deadline, payer, resourceId, and referenceHash into the intent hash + witness signature. This prevents “paid for X, fulfilled for Y” failures when payment routing or recipients are dynamic.
5) Failure‑mode hardening for real networks
Balance‑delta checks, replay protection, cancellation, trusted routers, and token allowlists are built in. This turns a spec into infrastructure operators can run with confidence.
6) The layer that matters more as x402 grows
Once payments live inside HTTP, the differentiator becomes how safely and consistently you authorize, settle, replay‑protect, and meter usage on‑chain. That is exactly what the Router / Registry / SessionStore stack is optimized for.
One‑line summary you can reuse
“x402 V2 standardizes how to request/pay over HTTP; X402Flex standardizes how to settle and enforce it on EVM—with multi‑rail funding, cryptographic intent binding, and session‑based spend controls that make agentic and pay‑per‑request commerce safe.”
Want to integrate?
If you want to build on X402Flex (or run your own router), start with: