Verify it yourself

Everything in this section is meant to be checked, not taken on faith. This page collects the commands and the on-chain evidence in one place. Run the curl commands against the live facilitator, and open any transaction hash on a block explorer to confirm it settled.

The facilitator runs on Railway and cold-starts in up to about 13 seconds if it has been idle. If the first request is slow, run it twice.

Check the live facilitator

All five commands were run against the live deployment and return the responses shown (abridged).

# 1. Both schemes on stellar:testnet, with sponsored fees advertised truthfully.
curl -s https://facilitator.rail402.dev/supported | jq
# {
#   "kinds": [
#     { "x402Version": 2, "scheme": "exact", "network": "stellar:testnet",
#       "extra": { "areFeesSponsored": true } },
#     { "x402Version": 2, "scheme": "upto",  "network": "stellar:testnet",
#       "extra": { "uptoContract": "CCMM3FMGEH7FHRYXZ3WQDQCTIWDXGZBGW7D4UT7NKH34SUQACYC3U54X",
#                  "areFeesSponsored": true } }
#   ],
#   "extensions": ["bazaar"],
#   "signers": { "stellar:*": ["GBRVXNCL55KOEB7WU3BPSEL34PSUH63UCIFPZDUBIVJBRRG5ZB7V4YR7"] }
# }

# 2. Durable catalog, live signer count, degraded-mode field.
curl -s https://facilitator.rail402.dev/health | jq
# { "status": "ok", "networks": ["stellar:testnet"], "signers": 1,
#   "catalog": { "entries": 3, "storage": "durable" } }

# 3. Browse the Bazaar catalog (the list key is `items`).
curl -s "https://facilitator.rail402.dev/discovery/resources?limit=2" | jq
# { "x402Version": 2, "items": [ { "resource": ".../demo/convert", "accepts": [...] } ],
#   "pagination": { "limit": 2, "offset": 0, "total": ... } }

# 4. Natural-language search (the array key is `resources`, not `items`).
curl -s "https://facilitator.rail402.dev/discovery/search?query=tide" | jq
# { "x402Version": 2, "resources": [ { "resource": ".../quote", ... } ] }

# 5. Confirm a settlement on chain. The fee source is the facilitator, not the buyer.
curl -s "https://horizon-testnet.stellar.org/transactions/3f6031ed4d3d17100992b1e003f9bcc6da51ef684cc1ba402432ae52166a903f" \
  | jq '{ successful, ledger, fee_charged, source_account }'
# { "successful": true, "ledger": 3879480, "fee_charged": "22973",
#   "source_account": "GDR7HR3T..." }   (the facilitator, sponsoring the fee)

Command 5 confirms two invariants at once. fee_charged is paid by source_account, which is the facilitator’s signer, so the fee is sponsored. That source is not the buyer whose auth entry moved the funds, so the settlement is non-custodial. See Fee sponsorship and the non-custodial invariant.

Settled transactions

One settlement per scheme, per payer type, per asset. Open any hash on stellar.expert using the form https://stellar.expert/explorer/testnet/tx/<hash>. These are regenerated by the canary suite and kept current in docs/status/.

Scheme	Payer	Asset	How	Transaction
`exact`	`G` keypair	self-issued	unmodified stock client	`3f6031ed…`
`exact`	`G` keypair	real USDC	SDK, default fee ceiling	`cfb8c0fd…`
`exact`	`G` keypair	real USDC	upstream e2e suite, stock axios	`52c62499…`
`exact`	`G` keypair	real USDC	upstream e2e suite, stock fetch	`5c5e2231…`
`exact`	`G` (MCP agent)	self-issued	agent, zero pre-integration	`0b149e8d…`
`exact`	`C` smart account	self-issued	`__check_auth`, via verify and settle	`168929e9…`
`upto`	`G` keypair	self-issued	3.5M of a 10M ceiling	`5e5d862c…`
`upto`	`G` keypair	real USDC	0.075 of a 0.20 ceiling	`1fb4452b…`
`upto`	`C` smart account	self-issued	750k of a 2M ceiling, budget reconciled	`0d78d7cf…`

The two upstream-e2e rows are settlements produced by the unmodified x402 repository’s own test clients pointed at Rail402, in real testnet USDC (Conformance). The C-smart-account upto row demonstrates budget reconciliation: the on-ledger budget afterwards reads the actual 750k, not the 2M ceiling, which is only reachable if the settlement contract called the policy’s release (Smart accounts).

Deployed contracts

Both contracts are deployed on testnet and reproduce byte-for-byte from source with stellar contract build. Open either at https://stellar.expert/explorer/testnet/contract/<address>.

Contract	Address	wasm sha256
`upto` settlement	`CCMM3FMG…C3U54X`	`a19f563e764dfd52a0d229c063e7ac1a1b36f6a976f552a8e19b91ee8e4ef84a`
Agent spending policy	`CC3XJMYT…F7LEC`	`6d9307303a7f11e14b98530688e1cccb259fc35c537b71561429e77bc4aaa232`

The smart-account layer reuses OpenZeppelin’s audited stellar-accounts. The account and its ed25519 verifier (CCC4DCEZ…) are OpenZeppelin’s; only the budget policy above is Rail402’s. See Smart accounts.

Upstream contributions

Four Rail402 contributions are public upstream.

Contribution	Where
Merged into Stellar Developer Docs	`stellar/stellar-docs#2718`
`__check_auth` client fix (smart-account signing)	`x402-foundation/x402#3018`
`upto` for Stellar, proposed	`stellar/x402-stellar#71`
`exact` and `upto` design, with SDF engineers	`stellar/x402-stellar#72`

Run the whole loop yourself

The end-to-end flow, settling a real payment, cataloging it, and finding it by natural-language search, is one command against the live facilitator.

git clone https://github.com/tolgayayci/rail402 && cd rail402 && pnpm install
pnpm canary discovery-loop --facilitator https://facilitator.rail402.dev

It runs a stock @x402 client through verify, settle, catalog, and search, and prints the settled transaction hash. The conformance harness (@rail402.dev/conformance) does the same against the upstream x402 e2e suite.

Next steps

Wire-level conformance

How Rail402 interoperates with stock x402 clients.

The settlement path

What the facilitator does with a signed auth entry.

The upto scheme

The contract behind the metered rows above.

Deployment

Where and how the live service runs.

Overview

Settlement on Stellar

Metered payments (upto)

Discovery & agents

Search & retrieval

Conformance & operations

Verify it yourself

Check the live facilitator

Settled transactions

Deployed contracts

Upstream contributions

Run the whole loop yourself

Next steps

Wire-level conformance

The settlement path

The upto scheme

Deployment

​Check the live facilitator

​Settled transactions

​Deployed contracts

​Upstream contributions

​Run the whole loop yourself

​Next steps

Wire-level conformance

The settlement path

The upto scheme

Deployment

Check the live facilitator

Settled transactions

Deployed contracts

Upstream contributions

Run the whole loop yourself

Next steps