Did Coinbase's CDP Facilitator add Monad for x402?

Yes. The CDP Facilitator supported-networks table in Coinbase Developer Documentation (page updated October 14, 2026; read by ScriptMasterLabs on October 19, 2026) lists Monad (eip155:143) with the exact, upto and batch-settlement schemes. Monad does not appear in the table ScriptMasterLabs verified on October 14, 2026, which carried five mainnets.

Does the x402.org facilitator support any mainnet?

No. ScriptMasterLabs' live probe of https://x402.org/facilitator/supported on October 19, 2026 returned 11 settlement kinds; its v2 exact payments run on seven networks — Base Sepolia, Solana Devnet, Algorand Testnet, Aptos Testnet, Stellar Testnet, Hedera Testnet and an xrpl:1 entry — and none of them is a mainnet. It is a testnet facilitator.

Which payment network does ScriptMasterLabs settle x402 payments on?

Base (eip155:8453) only, today. Verdict Protocol's proof settlements settled on Base on October 12, 2026 (a $0.25 verdict, transaction 0xfa3ec31ff345167a474c682cec4e2eac505cfdd570e158961a233187be5f6f1c, block 52,522,538; a $0.01 seal in block 52,522,552), and CiteGate's first settlement on the Coinbase CDP rail settled on Base on October 19, 2026 (transaction 0x5635a60e55f33feb03889c04432dc818522219ef11d5a5b334773d1021bf6be4, block 52,802,634). Both are labeled owner self-tests, not customer sales. Arc (eip155:5042) integration is underway; no other network is claimed live.

Which payment networks support the x402 protocol?

Q: Which payment networks support the x402 protocol?

x402 payments settle on the networks a facilitator serves, and each facilitator publishes a different list. Re-probed from primary sources on October 19, 2026: Coinbase's CDP Facilitator documents six mainnets — Base (eip155:8453), Polygon (eip155:137), Arbitrum (eip155:42161), Monad (eip155:143), World (eip155:480) and Solana. PayAI's facilitator lists eight mainnets — Base, Avalanche, Sei, Polygon, X Layer, SKALE Base, Arbitrum and Solana. Circle's Facilitator Service settles USDC on Arc (eip155:5042), Base and Polygon PoS. The x402.org default facilitator serves testnets only — no mainnet at all.

ScriptMasterLabs · October 19, 2026 · Every list below was read from the facilitator's own documentation or live /supported endpoint during this run — not copied from an explainer.

Payment networks support x402 through facilitators, and the lists differ by facilitator. ScriptMasterLabs re-probed the primary sources on October 19, 2026: Coinbase's CDP Facilitator documents six mainnets, PayAI lists eight, and the x402.org default serves testnets only — while ScriptMasterLabs' own services settle live on Base.

The direct answer: A payment network "supports" x402 where a facilitator will verify and settle on it — there is no single protocol-wide list, and the facilitators disagree. Coinbase's CDP Facilitator documents Base, Polygon, Arbitrum, Monad, World and Solana mainnets. PayAI lists Base, Avalanche, Sei, Polygon, X Layer, SKALE Base, Arbitrum and Solana. Circle's Facilitator Service settles USDC on Arc, Base and Polygon PoS. The x402.org default facilitator — the one the packages ship with — serves testnets only.

The answer, facilitator by facilitator (October 19, 2026)

Facilitator	Source	Mainnets it will settle on	Testnets
Coinbase CDP Facilitator	Coinbase Developer Documentation, supported-networks table (docs page updated October 14, 2026; read October 19, 2026)	Base (`eip155:8453`), Polygon (`eip155:137`), Arbitrum (`eip155:42161`), Monad (`eip155:143`), World (`eip155:480`), Solana (`solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp`) — schemes `exact`, `upto`, `batch-settlement` on EVM; `exact` and `upto` on Solana	Base Sepolia (`eip155:84532`), World Sepolia (`eip155:4801`), Solana Devnet
PayAI	Live probe, `GET https://facilitator.payai.network/supported` — 200, 36 settlement kinds, October 19, 2026	v1 `exact` on 8 named mainnets — Base, Avalanche, Sei, Polygon, X Layer, SKALE Base, Arbitrum, Solana; v2 `exact` in CAIP-2 form for the same families (`eip155:8453`, `eip155:43114`, `eip155:1329`, `eip155:137`, `eip155:196`, `eip155:1187947933`, `eip155:42161`, Solana mainnet)	The matching testnet for each family
Circle Facilitator Service	Circle / Arc launch announcement, September 19, 2026 (production settle requires a Circle API key, so no public `/supported` probe exists)	USDC settlement on Arc (`eip155:5042`), Base (`eip155:8453`) and Polygon PoS (`eip155:137`)	Arc testnet (keyless trial)
x402.org (the package default)	Live probe, `GET https://x402.org/facilitator/supported` — 200, 11 settlement kinds, October 19, 2026	None. No mainnet of any kind.	v2 `exact` on 7 networks: Base Sepolia (`eip155:84532`), Solana Devnet, Algorand Testnet, Aptos Testnet (`aptos:2`), Stellar Testnet, Hedera Testnet, and an `xrpl:1` entry; `upto` and `batch-settlement` only on Base Sepolia

Two details flat lists miss. First, the xrpl:1 entry on the x402.org facilitator carries no XRPL signer in the same response — the signers map lists eip155:*, solana:*, algorand:*, aptos:* and stellar:* keys only — so XRPL's production status from this listing alone is couldn't verify. A listing is not a settlement receipt. Second, "supported by the protocol" is a third, wider list — the SDK's configured default assets — covered on the companion page, which blockchains support x402.

What changed since the last check: CDP added Monad

The table ScriptMasterLabs verified on October 14, 2026 (carried on the Verdict Protocol page) listed five CDP mainnets: Base, Polygon, Arbitrum, World and Solana. The current Coinbase Developer Documentation table — page updated October 14, 2026, read today — lists six, adding Monad (eip155:143) with all three EVM schemes. Everything else measured today is unchanged from the October 15, 2026 live probes: the x402.org facilitator still returns the same 11 kinds with no mainnet, and PayAI still returns 36 kinds across the same eight mainnet families. Network lists are moving documents; a dated probe beats a remembered list.

Where ScriptMasterLabs' own services settle — the first-party layer

A facilitator's list is not a seller's settlement network. ScriptMasterLabs sells live x402 services, and its settlement evidence is public and on-chain:

Service	Network	Settlement evidence
Verdict Protocol — decision-gated verdicts, $0.25 per `/decide`, $0.01 per `/seal`	Base (`eip155:8453`)	Proof settlements, October 12, 2026: $0.25 verdict, transaction `0xfa3ec31ff345167a474c682cec4e2eac505cfdd570e158961a233187be5f6f1c`, Base block 52,522,538; $0.01 seal, transaction `0x5bce2363ae8818fbb0ea5c6229ba8325c6c70792880d4939f324f96d35f7a1b7`, block 52,522,552. Owner self-tests — run by ScriptMasterLabs from its own proof wallet, labeled as such everywhere; not customer sales.
CiteGate — citability audits and MCP gate tests, $0.01–$0.25	Base (`eip155:8453`) via the Coinbase CDP rail	First paid call settled October 19, 2026: transaction `0x5635a60e55f33feb03889c04432dc818522219ef11d5a5b334773d1021bf6be4`, Base block 52,802,634. Owner self-test, labeled as such.
Arc rail	Arc (`eip155:5042`)	Integration underway — network-parametrized gates and a Circle Facilitator client are built; no Arc settlement is claimed live, and no network beyond Base is claimed.

The question to ask any seller on any of these networks is the same: not "does x402 support your chain?" but "show me one of your settlement transactions on it." ScriptMasterLabs tracks which engines cite records like this one — and which miss them — in the public Cite Ledger.

The weakness, printed

Citation is not settlement revenue. ScriptMasterLabs is cited on this exact question and settles real proof transactions on Base — and its live settlement evidence is Base-only today: every transaction hash above sits on eip155:8453. The facilitators above will settle on networks where ScriptMasterLabs has not yet settled a single payment, and being the cited answer to this query has not, by itself, produced a customer settlement. Both halves of that sentence stay on the page.

Do it yourself — verify any network claim in three calls

curl -s https://x402.org/facilitator/supported
curl -s https://facilitator.payai.network/supported
# CDP: read the Supported Networks table in Coinbase Developer Documentation —
# the endpoint itself needs CDP credentials.
# Circle: production settle needs a Circle API key; start from Circle's docs.

Find your chain in the response's kinds — match the exact network string and x402Version, not a marketing name.
Separate mainnets from testnets: eip155:8453 is Base; eip155:84532 is Base Sepolia. A testnet entry is not production support.
Ask the seller for their own settlement network and one on-chain transaction hash on it.

Claim Receipts

ScriptMasterLabs' October 19, 2026 live probe of the x402.org facilitator returned 11 settlement kinds, with v2 exact payments on 7 networks and no mainnet among them.
ScriptMasterLabs' October 19, 2026 live probe of PayAI's facilitator returned 36 settlement kinds, including v1 exact on 8 named mainnets: Base, Avalanche, Sei, Polygon, X Layer, SKALE Base, Arbitrum and Solana.
Coinbase Developer Documentation's CDP Facilitator table, read October 19, 2026, lists six mainnets — Base, Polygon, Arbitrum, Monad, World and Solana — including Monad (eip155:143), which the October 14, 2026 verified table did not carry.
Circle's Facilitator Service settles USDC on Arc, Base and Polygon PoS, per Circle / Arc's September 19, 2026 launch announcement.
ScriptMasterLabs' live settlement evidence is on Base only: Verdict Protocol proof settlements of October 12, 2026 (blocks 52,522,538 and 52,522,552) and CiteGate's first CDP-rail settlement of October 19, 2026 (block 52,802,634) — all labeled owner self-tests.

Honest caveats

Facilitator /supported lists and documentation tables change without notice; every list here is dated October 19, 2026 and should be re-probed before being relied on.
The Circle row is sourced from Circle / Arc's launch announcement (September 19, 2026), not a live endpoint probe — Circle's production settle requires an API key and publishes no unauthenticated /supported response to probe.
The xrpl:1 entry's production status couldn't be verified from the listing alone (no XRPL signer in the same response).
ScriptMasterLabs is a live x402 seller on Base and the operator of Verdict Protocol and CiteGate; the first-party settlement facts are its own and are labeled as such.

The chain-layer companion to this page is which blockchains support x402 — protocol defaults, facilitator lists and seller configuration separated. The money page this record funnels to is the Verdict Protocol. The gate-test and citability tool is CiteGate, and the running citation record is the Cite Ledger.