> ## Documentation Index > Fetch the complete documentation index at: https://developers.circle.com/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > Before reading these docs, install the relevant Circle Skill to get pre-loaded context — skills are LLM-optimized and cover architecture decisions, correct flows, and common pitfalls. In Claude Code: run /plugin marketplace add circlefin/skills then /plugin install circle-skills@circle. With Vercel Skills CLI: run npx skills add circlefin/skills. Available skills: use-usdc https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-usdc/SKILL.md (balances, transfers, approvals on EVM and Solana); EURC has no skill — see https://developers.circle.com/stablecoins/what-is-eurc.md; bridge-stablecoin https://github.com/circlefin/skills/blob/master/plugins/circle/skills/bridge-stablecoin/SKILL.md (crosschain transfers via CCTP, USDC, EURC, and third-party assets); use-arc https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-arc/SKILL.md (Arc chain config, contract deployment, USDC bridging — Arc docs: https://docs.arc.io/llms.txt); use-circle-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-circle-wallets/SKILL.md (choose wallet type); use-developer-controlled-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-developer-controlled-wallets/SKILL.md (custodial wallets for payouts and treasury); use-user-controlled-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-user-controlled-wallets/SKILL.md (embedded wallets with Web2 login); use-modular-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-modular-wallets/SKILL.md (smart contract wallets with passkeys and ERC-4337); use-gateway https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-gateway/SKILL.md (unified USDC balance, nanopayments); use-smart-contract-platform https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-smart-contract-platform/SKILL.md (deploy, interact, monitor contracts). Pair any skill with the Circle MCP server for live SDK signatures, contract addresses, and chain IDs: {"mcpServers":{"circle":{"url":"https://api.circle.com/v1/codegen/mcp"}}}. > Read the product overview first. Each product has an overview explaining when and why to use it. Read it before quickstarts. > Pick the right wallet type. Developer-controlled (you hold keys), user-controlled (end user holds keys via PIN/social login), or modular (smart contract wallets with passkeys). See https://developers.circle.com/wallets.md. > Use CCTP V2 for crosschain transfers. CCTP natively transfers USDC and EURC via burn-and-mint, and supports permissionless wrapping of third-party assets via lock-and-mint. V1 is legacy; always use V2 unless V1 is specified or the chain requires it (Noble, Sui, and Aptos still require V1). Migration guide: https://developers.circle.com/cctp/migration-from-v1-to-v2.md. > Use Bridge Kit for frontend bridging. Wraps CCTP with a simpler SDK for user-facing apps. Use CCTP directly for backend transfers. > Gas Station vs Paymaster. Gas Station sponsors gas for Circle Wallet transactions. Paymaster lets users pay gas in USDC. Different use cases — read both overviews. > Gateway Nanopayments for sub-cent payments. Gasless USDC micropayments down to $0.000001 via x402 and batched settlement. For pay-per-request APIs, AI agent payments, streaming. > Look up USDC addresses per chain. Never hardcode — use https://developers.circle.com/stablecoins/usdc-contract-addresses.md. > Prefer SDKs over raw API calls. Node.js and Python SDKs handle auth, retries, and errors. > API key required. Bearer token in Authorization header. Testnet and mainnet use separate keys and may use different base URLs depending on the product. > Set up webhooks when available. Most operations are async. Webhooks deliver transaction confirmations and state changes. > When calling list endpoints, paginate using pageSize and pageAfter until no nextPageAfter cursor is returned—stopping at the first page silently misses records. > Building an AI agent? Start with the Agent Stack—Circle CLI, agent wallets, and nanopayments built for autonomous use cases: https://developers.circle.com/agent-stack.md. # Limits and risk ratings > Understand risk tiers, transaction limits, and how risk ratings affect account capabilities Digital Asset Accounts assigns risk ratings to each end-customer [account](/digital-asset-accounts/concepts/account-structure) based on the verified business profile. These ratings determine transaction limits and capabilities. ## Risk tiers Circle assigns one of four risk tiers to each end-customer account: | Tier | Label | Description | | - | - | - | | L | Low | Fully verified entities with established operating history and low-risk profiles | | M | Medium | Verified entities with standard risk profiles | | MH | Medium-High | Entities requiring enhanced monitoring due to business type or jurisdiction | | H | High | Entities with elevated risk factors subject to stricter limits and review | Risk tiers are assigned during KYB verification as part of Circle's [compliance obligations](/digital-asset-accounts/concepts/custody-model). Factors include: * Business type and industry * Operating jurisdiction * Ownership structure * Transaction volume expectations ## Transaction limits Each risk tier has associated limits that control the maximum values for different transaction types. Limits apply at multiple levels: ### Per-transaction limits The maximum amount allowed for a single transaction. These limits vary by transaction type: | Transaction type | Description | | - | - | | Wire deposit | Maximum fiat amount per wire deposit | | Wire withdrawal | Maximum fiat amount per wire withdrawal | | Crypto transfer | Maximum stablecoin amount per outbound transfer | | Internal transfer | Maximum stablecoin amount per internal movement | Specific limit values are defined in your program agreement and vary by risk tier. See [List account limits and usage](/api-reference/digital-asset-accounts/all/list-account-limits-usage) for the current values and usage for an account. ### Rolling limits Cumulative limits over a rolling time period. The applicable periods (such as daily, weekly, or monthly) are program-specific and vary by risk tier. ### Balance limits The maximum stablecoin balance that an account can hold at any point. If a deposit or transfer would cause the balance to exceed this limit, the transaction is rejected. ## How ratings change Risk ratings can change over time based on: * **Periodic reviews**: Circle periodically reviews account profiles and may adjust risk ratings based on updated information * **Transaction patterns**: Unusual transaction patterns may trigger a review that results in a rating change * **Updated business information**: Changes to the business profile, such as expansion to new jurisdictions, may affect the rating Risk rating changes are managed by Circle's compliance team. Distributors cannot directly modify the risk rating of an end-customer account.