Build onchain financial experiences faster with SDKs
App Kits is an SDK suite that gives developers a consistent way to quickly embed onramp,1 bridge, earn, borrow,2 and other onchain financial primitives into their apps.
Core onchain actions, one standardized developer experience
Adopt App Kit SDKs to access multiple capabilities, helping teams ship faster and simplify development.
onramp()1
Bring a seamless fiat-to-crypto funding experience to your app using familiar payment methods.
1// Fetch a session minted on your server (requires session route on server)
2const session = await kit.onramp.fetchSession({
3 url: "/api/onramp/sessions",
4 body: {
5 userId: "user-123",
6 destinationAddress: "USER_WALLET_ADDRESS",
7 },
8});
9
10// Mount the widget inline
11const widget = kit.onramp.mountIframe({
12 session,
13 container: document.getElementById("onramp-root")!,
14 onDepositSettled: ({ payload }) => console.log("settled", payload),
15});earn()
Embed in-app earn experiences without the complexity of stitching together DeFi infrastructure.
1// Fetch vault details
2const { vaults } = await kit.earn.exploreVaults({
3 chain: "Arc_Testnet",
4 sortBy: "apy",
5});
6
7// Deposit into the first vault
8const result = await kit.earn.deposit({
9 from: { adapter, chain: "Arc_Testnet" },
10 vaultAddress: vaults[0].vaultAddress,
11 amount: "10.00",
12});borrow() Coming soon2
Offer BTC-backed USDC borrowing without building or managing the underlying DeFi infrastructure. (Coming soon)
1// Borrow 1000 USDC against cirBTC
2const result = await kit.borrow({
3 from: { adapter: viemAdapter, chain: "Arc_Testnet" },
4 marketId: "0x1111111111111111111111111111111111111111111111111111111111111111",
5 borrowAmount: "1000.0",
6});bridge( )
Integrate CCTP using the recommended approach for moving USDC across supported chains without building custom crosschain transfer logic.
1// Transfer 1.00 USDC from Solana to Arc
2const result = await kit.bridge({
3 from: { adapter: solanaAdapter, chain: 'Solana_Devnet' },
4 to: { adapter: viemAdapter, chain: 'Arc_Testnet' },
5 amount: '1.00',
6});
7
8send( )
Standardize token transfers across wallets and supported blockchains through a single SDK interface.
1// Send 1.00 USDC to a wallet on Arc Testnet
2const result = await kit.send({
3 from: { adapter: chain: "Arc_Testnet" },
4 to: { "RECIPIENT_ADDRESS" },
5 amount: "1.00",
6 token: "USDC",
7});
8swap( )
Add swap functionality across assets and chains without managing routing, liquidity, or provider integrations yourself.
1// Swap 1.00 USDC to EURC
2const result = await kit.swap({
3 from: { adapter: viemAdapter, chain: "Arc_Testnet" },
4 tokenIn: "USDC",
5 tokenOut: "EURC",
6 amountIn: "1.00",
7});unifiedBalance( )
Support chain-abstracted balances that enable faster crosschain USDC access without extra bridging.
1// Deposit 1.00 USDC into the Unified Balance from Base
2const depositBase = await kit.unifiedBalance.deposit({
3 from: { adapter: viemAdapter, chain: "Base_Sepolia" },
4 amount: "1.00",
5 token: "USDC",
6});
7// Deposit 1.00 USDC into the Unified Balance from Arbitrum
8const depositArb = await kit.unifiedBalance.deposit({
9 from: { adapter: viemAdapter, chain: "Arbitrum_Sepolia" },
10 amount: "1.00",
11 token: "USDC",
12});
13// Spend 1.50 USDC from the Unified Balance on Arc
14const spendResult = await kit.unifiedBalance.spend({
15 amount: "1.50",
16 from: { adapter: viemAdapter },
17 to: {
18 adapter: viemAdapter,
19 chain: "Arc_Testnet",
20 recipientAddress: "0xRecipientAddress",
21 },
22});Open and interoperable SDKs
Built to work seamlessly with Circle products like CCTP and USDC, App Kits also supports third-party wallets, tokens, and integrations so teams can build across chains.
Integrate with your existing wallets, frameworks, and infrastructure — including third-party wallet providers, viem, ethers.js, and your own RPC endpoints.
Build on Circle infrastructure today and expand to new assets, chains, protocols, and capabilities through the same SDK as the platform evolves.
Configure revenue sharing within supported transaction flows without requiring separate contracts or fee logic management.
Embed Onchain Financial Flows with App Kits
Launch onchain experiences faster with ready-to-integrate fund flows.
Acquire assets
Onramp1 lets your users buy USDC in your app using familiar payment methods, including Apple Pay, Google Pay, debit cards, and bank transfers.
Move assets
Send, Swap, Bridge, and Unified Balance let users access and move tokens across supported chains without stitching together custom integrations.
Tools you need to build onchain finance
Whether you're integrating a single financial capability or building a complete onchain application, App Kits gives you the tools you need to ship faster on Circle infrastructure.
Resources
View the list of supported assets and blockchains.
Learn how to swap tokens across chains and create custom fees.
1. Onramp availability and supported payment methods vary by region. At launch, Onramp Kit is available in the EU, UK, and US.
2. Borrow is available on Arc testnet and planned, but not yet available, on mainnet. Availability, timing, and functionality may change.
3. Borrow currently supports BTC as collateral. Support for ETH and additional collateral assets is planned over time.
4. Certain App Kits SDKs integrate with third-party protocols and smart contracts that are not owned or controlled by Circle and may be subject to separate terms, risks, and availability.
5. At launch, Earn Kit supports Morpho vaults with BTC and ETH as collateral. Support for additional third-party markets and collateral types is planned over time.
Sample apps provided for demonstration and educational purposes only, intended for Arc testnet use only, and not production-ready. See Arc.io for more.
App Kits is offered by Circle Technology Services, LLC ("CTS"), a software provider. CTS does not provide regulated financial, legal, or advisory services and is not responsible for the content, accuracy, legality, or functionality of third-party applications or services integrated with App Kits. Integrators are solely responsible for their own compliance, including obtaining any necessary licenses. App Kits has not been reviewed or approved by any regulatory authority. Features may change at any time. Nothing herein constitutes a commitment, warranty, or guarantee; legal, regulatory, tax, or investment advice; an offer to sell any security or financial instrument; or an endorsement of any protocol, strategy, or transaction.
Arc Onramp is technology infrastructure provided by Circle Technology Services, LLC that connects you to third-party identity verification and payment services. Arc Onramp Terms and third-party terms apply. Onramp does not hold, control, or custody your funds or assets. Offramp not yet available. For questions, visit the Arc Help Center.
CCTP is a crosschain messaging infrastructure service provided by Circle Technology Services, LLC ("CTS"). CCTP is non-custodial; CTS does not hold, control, manage, or transfer user assets or act as a transfer agent, registrar, broker-dealer, investment adviser, or clearing agency. CCTP is not a financial, payment, or advisory service and has not been reviewed or approved by NYDFS or any other regulatory authority. Transfers are irreversible; CTS cannot recover assets sent to an incorrect address. CTS does not vet, endorse, or back third-party assets; such assets are subject solely to the applicable third-party terms and risks. Issuers are solely responsible for their services and compliance with applicable laws. Any fee estimates are non-binding previews; actual fees may differ. Assets are subject to a number of risks, including, but not limited to, price volatility and smart-contract, relay, and bridge vulnerabilities. Availability is subject to change. Developer terms apply.
Unified Balance Kit is a software development kit (“SDK”) provided by Circle Technology Services, LLC ("CTS"). CTS is a software provider and does not provide regulated financial or advisory services. Not reviewed or approved by NYDFS or any other regulatory authority. You are solely responsible for services you provide to users, including obtaining any necessary licenses or approvals and otherwise complying with applicable laws in all jurisdictions where your application is made available.
Unified Balance Kit is non-custodial. Funds are held in Gateway smart contracts and are not held or controlled by CTS at any time. Blockchain transactions are irreversible. Fee estimates are previews only; actual fees may differ. Transfer times vary by chain, route, and network conditions and are not guaranteed. Permissionless withdrawals are subject to a 7-day delay. Features may be modified, delayed, or discontinued at any time. Developer Terms apply.
Earn Kit is intended to provide software infrastructure and technical tooling that may enable third parties to build or offer access to certain vault-related functionality for their own users. Each integrator is solely responsible for ensuring that its use of the Earn Kit, including how it structures, offers, markets, monetizes, or supports related products and services, complies with all applicable laws and regulations. By providing the Earn Kit, Circle is providing software infrastructure and technical tools only and does not provide legal, tax, or regulatory advice. Integrators should consult their own advisors before launching or offering any related product or service.
USDC and EURC areis issued by regulated affiliates of Circle. See Circle’s list of regulatory authorizations.
Arc is an open L1 blockchain launched by Arc Network Services LLC ("Arc LLC") and operated by a permissioned validator set. Arc LLC provides software services only and does not offer regulated financial or advisory services. Arc has not been reviewed or approved by the New York State Department of Financial Services or any other regulatory authority.
The Arc network is provided "as is" and "as available." Use of Arc involves inherent risks associated with blockchain technology, including smart contract vulnerabilities, network disruptions, and the absence of recourse for transaction errors or losses. The ability to transact on Arc depends on the ability to obtain and use USDC to pay gas fees. Neither Arc LLC nor any permissioned validator is responsible for the content, accuracy, legality, or functionality of third-party applications, protocols, or services built on or integrated with Arc. You are solely responsible for features or services you provide to users, including obtaining any necessary licenses or approvals and otherwise complying with applicable laws.
All Arc features may be modified, delayed, or cancelled at any time without notice. Nothing herein constitutes a commitment, warranty, guarantee or legal, regulatory, tax, or investment advice.