Oneliq: One Interface for All Stablecoin Flows

Oneliq is a non-custodial interface for Circle's stablecoin infrastructure on Arc Testnet. It does not custody funds, run its own bridge, or operate its own AMM. Every settlement operation calls into a Circle contract: App Kit Swap, CCTP V2, Circle Gateway, or Circle Programmable Wallets. Oneliq is the form, the route planner, and the transaction history. Circle is the settlement layer.

The infrastructure it surfaces

Before looking at the products individually, it helps to know what Circle technology each one calls. Oneliq is a thin UX layer; the interesting engineering is in the protocols underneath.

Circle App Kit Swap handles the USDC-to-EURC exchange on Arc Testnet. The exchange rate is fetched live from Circle's aggregator at quote time. Oneliq presents the quote, shows slippage, and submits the transaction when you confirm. The swap contract is Circle's.

CCTP V2 is the burn-and-mint bridge that moves USDC between chains without wrapping. When Trade routes a cross-chain transfer, it submits a burn transaction on the source chain, then Circle's attestation service authorizes a mint on the destination. Fast mode settles in roughly 20 seconds with a small Circle fee. Standard mode settles in 13 to 19 minutes with no fee. Oneliq calls the same CCTP V2 contracts deployed across all eight supported chains.

Circle Gateway is the escrow contract that powers Unified Balance. Depositing USDC into Gateway locks it in escrow on the source chain and increases your chain-agnostic balance. Spending from Gateway instructs Circle to release USDC from the appropriate source chain escrow and mint it at a destination of your choice. The spend authorization is an EIP-712 BurnIntent signature, not a separate on-chain transaction per source chain.

Circle Programmable Wallets is the contract infrastructure behind Agent. The auto top-up and scheduled send flows create and execute recurring transfer policies via Programmable Wallets. Agent is the first Oneliq product where Circle's wallet automation layer is directly exposed to end users.

What ships today

Trade: three settlement routes from one form

Trade is Oneliq's primary interface for moving value across chains. The form takes a source token, a destination token, a destination chain, and an amount. The route planner determines whether the operation requires a swap, a bridge, a Gateway spend, or some combination of the three. The assembled route is shown as a step pipeline before any signature is requested.

A swap on Arc Testnet uses Circle App Kit and settles in roughly five seconds. A bridge between any two of the eight supported chains uses CCTP V2. A Gateway spend uses a BurnIntent signature and settles in roughly 30 seconds. Complex routes chain these steps. Converting EURC on Arc to USDC on Base Sepolia, for example, runs as a two-step pipeline: App Kit swap on Arc, then CCTP V2 bridge to Base Sepolia. The source picker separates wallet balances from Gateway deposits in a two-column panel, and a Unified Balance row aggregates Gateway deposits across multiple chains when more than one is funded. Read the Trade deep-dive for a full walkthrough of each routing path.

Balance: one USDC pool across eight chains

Balance surfaces Circle's Unified Balance API through three deposit operations and three spend modes. Depositing USDC from any of the eight supported chains puts it into Circle Gateway's escrow on that source chain. From that point the balance is chain-agnostic. The underlying USDC is held wherever you deposited it. What increases is an accounting entry in Circle's system, redeemable on any chain where Gateway is deployed.

When spending, you choose how the source funds are allocated. Auto mode lets Circle Gateway route from whichever chains hold enough balance, minimizing the number of source chains involved. Single mode draws the full amount from one chain you select. Manual mode lets you specify a custom per-chain split. All three modes deliver standard USDC to the recipient address on the chosen destination chain. The recipient does not need a Unified Balance account. See the Balance post for the full deposit-and-spend walkthrough.

Agent: automated USDC transfers (preview)

Agent is in public preview. It exposes two automation modes built on Circle Programmable Wallets. Auto top-up monitors a wallet balance on a selected chain and issues a USDC transfer when the balance drops below a configured threshold. Scheduled send issues recurring transfers on a fixed interval: once, daily, weekly, or monthly. Both modes store the policy parameters on-chain via the Programmable Wallets contract. A daily safety cap limits total outflow. Policies can be paused or revoked at any time from the same interface.

The key design constraint is that Agent can only automate flows between wallets you control. The recipient address for both modes is set at policy creation time and cannot be changed without revoking and recreating the policy. This is not a limitation of Oneliq's interface; it reflects the access model of Circle Programmable Wallets, which requires explicit ownership proof before modifying any policy.

History: cross-chain activity in one view

History collects and displays completed operations across all eight chains in a single feed: swaps, CCTP bridges, Gateway spends, Gateway deposits, and agent executions. Each entry links to the transaction on the relevant chain explorer. The feed updates in real time as the connected wallet's operations confirm.

History is read-only. It queries each chain's RPC and Arc's event logs. There is no centralized indexer behind it. If a chain's RPC is unreachable, entries for that chain may lag until the connection recovers.

The network: Arc Testnet

All five products run on Arc Testnet as their home chain. Arc is an EVM-compatible Layer 1 developed by Circle with two properties that matter structurally for Oneliq.

First, USDC is the native gas token. Every transaction on the network settles fees in USDC rather than a separate gas token. This means there is no "need ETH for gas" bootstrapping problem. USDC from your wallet or Gateway deposit is the same asset you use to pay for the transaction that moves it. This simplifies the balance model across all five products.

Second, Arc has deterministic sub-second finality. There are no reorgs on Arc. When a transaction confirms, it is confirmed. This matters for CCTP V2 because the bridge waits for source-chain finality before the attestation service processes the burn. Faster finality on Arc means faster bridge confirmation when Arc is the source chain.

The seven other chains Oneliq connects to are standard EVM testnets: Ethereum Sepolia, Base Sepolia, Avalanche Fuji, Arbitrum Sepolia, Optimism Sepolia, Polygon Amoy, and Unichain Sepolia. CCTP V2 and Circle Gateway are deployed on all eight.

What Oneliq is not

Oneliq does not custody funds. The interface submits transactions to contracts that Circle or the Arc Foundation deployed. Your wallet signs each transaction. Oneliq cannot pause, block, or redirect your assets at any point in the flow.

Oneliq does not run its own AMM, bridge, or Gateway contract. The contracts that execute each operation belong to Circle or the Arc Foundation. If those protocols have a bug, that bug exists regardless of whether Oneliq surfaces them or not. Oneliq's trust assumptions are the same as the trust assumptions of the underlying Circle products.

Oneliq does not have its own token. There is no governance token, no airdrop, no points program. Anyone claiming otherwise is running a scam.

Oneliq does not charge fees on swaps, bridges, or Gateway flows in the current testnet stage. The fees shown in the Trade form come from the underlying protocols: the Circle App Kit swap spreads, the CCTP V2 Fast Transfer fee, and the Gateway BurnIntent processing fee. These are Circle's fees, not Oneliq's.

Oneliq is a non-custodial frontend currently on Arc Testnet. Nothing here is financial advice. We don't custody funds; you always retain control of your wallet.