x402B is the Boson Protocol implementation of the x402-escrow-schema — a non-custodial escrow payment scheme for x402 HTTP servers.
It keeps x402's HTTP-native, gasless, single-round-trip UX and replaces the trusted-server payment model with Boson Protocol escrow. Funds enter a non-custodial Boson Diamond escrow at commit time; they release to the seller only after the buyer signals delivery (or the dispute window expires); a registered third-party dispute resolver can split funds and slash a seller bond if delivery fails.
The SDK is designed so that existing x402 servers and clients can adopt it as a drop-in addition. Servers add a Boson scheme to their accepts[] array; clients that understand the escrow scheme handle it, and those that don't fail cleanly with a structured "unsupported scheme" error — never an accidental settle.
All packages publish under @bosonprotocol/.
| Package | Purpose |
|---|---|
x402-core |
escrow scheme JSON schemas + TypeScript types; EIP-712 builders for FullOffer (protocol domain), the protocol meta-tx envelope, and the four BPIP-12 token-auth strategies (ERC-3009 ReceiveWithAuthorization, EIP-2612 Permit, Permit2, plain approve); exchange state machine model. |
x402-evm |
EVM-specific implementation. Calldata builders for ExchangeCommitFacet.createOfferAndCommit (deferred), OrchestrationHandlerFacet2.createOfferCommitAndRedeem (atomic on-chain redeem), and the MetaTransactionsHandlerFacet.executeMetaTransactionWithTokenTransferAuthorization envelope that carries them. Wraps @bosonprotocol/core-sdk. |
x402-server |
Framework-agnostic resource server. 402 builder, FullOffer signer wrapper, fulfillment negotiator, nextActions emitter, post-redeem endpoint set. Adapter sub-package: x402-server-express (further adapters planned). |
x402-client |
Framework-agnostic client. Interceptor that parses the 402, picks a fulfillment channel option and a token-auth strategy, signs the meta-tx + token authorization(s), retries, then drives post-redeem actions through whichever channel is preferred. Adapter sub-package: x402-client-fetch (further adapters planned). |
x402-facilitator |
Reference verify + settle service for the escrow scheme. Submits via MetaTransactionsHandlerFacet.executeMetaTransactionWithTokenTransferAuthorization. Adapter sub-package: x402-facilitator-express. |
x402-fulfillment |
Pluggable FulfillmentChannel interface + atomic / email / XMTP / webhook / IPFS-pointer implementations. |
x402-actions |
Channel registry, ChannelAdapter contract, and the nextActions envelope builder. Drives off the state-machine tables in x402-core to advertise legal next transitions on every server response and powers the post-redeem endpoint set. |
@bosonprotocol/core-sdk— contract calls, subgraph reads, meta-tx helpers, dispute helpers.@bosonprotocol/metadata— offer metadata schemas.@bosonprotocol/common— EIP-712 hashing helpers.
This repo implements the x402-escrow-schema specification. The generic spec defines the wire format, fulfillment channel interface, state machine, and nextActions envelope. x402B provides:
- The Boson-specific
OfferCommitment(BosonTypes.FullOffer, BPIP-10) - The meta-tx entry-point (
MetaTransactionsHandlerFacet.executeMetaTransactionWithTokenTransferAuthorization, BPIP-12) - Boson Diamond as the escrow contract
- The
boson-action-id prefix - Integration with
@bosonprotocol/core-sdkandbosonprotocol/agentic-commerce
| # | File | Status |
|---|---|---|
| 00 | boson-impl-00-overview.md | detailed |
| 01 | boson-impl-01-escrow-scheme.md | detailed — wire format source of truth |
| 02 | boson-impl-02-flows.md | detailed — sequence diagrams |
| 03 | boson-impl-03-fulfillment-channels.md | detailed — pluggable fulfillment channels |
| 04 | boson-impl-04-state-machine-and-next-actions.md | detailed — self-describing responses |
| 05 | boson-impl-05-server-sdk.md | stub |
| 06 | boson-impl-06-client-sdk.md | stub |
| 07 | boson-impl-07-facilitator.md | detailed — facilitator service contract |
| 08 | boson-impl-08-agent-mode.md | stub |
| 09 | boson-impl-09-seller-metadata.md | stub |