> ## Documentation Index > Fetch the complete documentation index at: https://a-identity.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Chains > Every chain A-Identity knows about, what is actually deployed on each, and which ones are wired end to end today. A-Identity is chain-agnostic by construction: one registry describes every chain, and one adapter per virtual machine does the work. Adding a chain is a data edit, not a new code path. The table below is the honest state of that registry. The vocabulary is exact. **Live** is the registry's status for the chains that carry the product today, and it has never meant "no caveats": Arc Mainnet is live with its first payments self-funded, Arc testnet still carries escrow and KYA, and each row states exactly what runs where, including what does not run there yet. **Beta** marks the testnet mirrors of live chains: wired and readable, test money. **Planned** means the descriptor exists so onboarding is a data edit, and nothing is deployed yet. | Chain | CAIP-2 | Status | What is deployed | | -------------------------------------------- | ------------------------------------------- | ------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [Arc Mainnet](/chains/arc#arc-mainnet) | `eip155:5042` | live | Agent #0 on the canonical ERC-8004 registry, an AgentSpendPolicy vault with real USDC, x402 via our EIP-3009 facilitator and Circle Gateway nanopayments | | [Circle Arc](/chains/arc) (testnet) | `eip155:5042002` | live | ERC-8004 identity, reputation and validation, ERC-8183 escrow, AgentSpendPolicy vaults, USDC | | [Stellar](/chains/stellar) | `stellar:pubnet` | live | An `AgentSpendPolicy` Soroban vault holding real Circle USDC under a 1 USDC daily cap, with a typed `DailyCapExceeded` refusal on the ledger; the Soroban x402 rail sells here too (first mainnet sale 2026-08-27, buyer signs an authorization entry and pays no fee). No ERC-8004 on either Stellar network: that standard is EVM-only | | [Stellar (testnet)](/chains/stellar) | `stellar:testnet` | beta | The same vault wasm plus the Soroban x402 rail end to end, in test money: the buyer signs an authorization entry and pays no fee | | Algorand | `algorand:wGHE2Pwdvd7S12BL5FaOP20EGYesN73k` | live | Native Circle USDC (ASA 31566704), x402 v2 through the GoPlausible facilitator: the buyer signs a fee-zero transfer and the atomic group's pooled fee covers it. First mainnet sale settled 2026-08-30 and counted only after our own indexer read; no ERC-8004 registry found on Algorand, so identity stays bridged | | Algorand (testnet) | `algorand:SGO1GKSzyE7IEPItTxCByw9x8FmnrCDe` | beta | The same x402 code path as mainnet, in test money, against the facilitator's testnet network | | [OKX X Layer](/chains/xlayer) | `eip155:196` | live | Canonical ERC-8004 identity; the trust oracle is listed here and sells over x402 | | [Robinhood Chain](/chains/robinhood) | `eip155:4663` | live | Canonical ERC-8004 identity and reputation, agent #0, and our own x402 facilitator settling in USDG | | [Celo](/chains/celo) | `eip155:42220` | live | Canonical ERC-8004 identity and reputation, agent #9759, x402 over USDC via the first-party Celo facilitator | | [Base](/chains/base) | `eip155:8453` | live | Canonical ERC-8004 identity and reputation registries, deployed by their authors and read live; agent #73232 is ours; x402 settles in native Circle USDC through our own EIP-3009 facilitator (first settlement 2026-08-28); plus the Gateway hop that mints on Base Sepolia | | [Robinhood Chain Testnet](/chains/robinhood) | `eip155:46630` | beta | The full canonical ERC-8004 trio plus a deployed AgentSpendPolicy vault | | [Celo Sepolia](/chains/celo) | `eip155:11142220` | beta | Same ERC-8004 pair as Arc, x402 over testnet USDC | | [Arbitrum One](/chains/arbitrum) | `eip155:42161` | live | Canonical ERC-8004 identity and reputation, agent #1259, and x402 settling in native Circle USDC through our own facilitator | | Avalanche C-Chain | `eip155:43114` | planned | Descriptor only | A backend test asserts that every CAIP-2 id in the registry appears on this page, so a chain cannot silently go missing here. It does not read the status column, which is maintained by hand. The machine-readable status is `GET /api/chains`, generated from the registry itself, and that is the copy to trust if the two ever disagree. ## What "deployed" means for identity The ERC-8004 registries are not ours. Their authors deployed them deterministically, so the same addresses appear on chain after chain, and where they were already present we simply read them. Where a piece was missing we reproduced it by replaying the canonical deployment calldata rather than forking a new contract, which is why the addresses still match everywhere. Two consequences worth stating plainly, because they are easy to get wrong: * A chain can carry an IdentityRegistry and no ValidationRegistry. On those chains a KYA result cannot be anchored on-chain. It is still verified and recorded, and we say so rather than reporting a zero that reads like a real count. * A chain can have a real settlement token and no canonical Circle USDC. Robinhood Chain is exactly that: the registry's USDC slot stays empty on purpose, and USDG is named as its own thing, because every generic USDC code path reads that slot. ## Settlement, chain by chain | Rail | How a payment settles | | --------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Arc | The buyer broadcasts an ERC-20 transfer; we verify the receipt ourselves. Also gasless Circle Nanopayments. | | X Layer | Through the OKX facilitator, as a listed ASP service. | | Celo | Through Celo's own first-party x402 facilitator, EIP-3009, buyer pays no gas. | | Robinhood Chain | Through **our own** facilitator, run because no published one serves this chain: EIP-3009, buyer pays no gas, and settlement is proven by a receipt carrying the matching Transfer log. | | Arbitrum One | The same facilitator and the same engine, settling in native Circle USDC. Other facilitators already serve this chain, so here you can compare ours against a baseline. The disclosed fee is lower because a settlement measurably costs less: 103569 gas at 0.02 gwei. | | Base | The same facilitator and the same engine again, settling in native Circle USDC with the signing domain proven against the live DOMAIN\_SEPARATOR. The first settlement's receipt (102828 gas at 0.006 gwei) is what set the disclosed fee. | | Stellar | Through our own Soroban facilitator, on both networks: the buyer signs an authorization entry (no per-token domain to prove; the protocol fixes the preimage), we assemble and pay the fee, and a sale counts only once the SEP-41 transfer event bound to that authorization's nonce is read back. |