> ## Documentation Index > Fetch the complete documentation index at: https://docs.gethevn.com/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > HEVN is payments software: an API and app over a Base smart wallet. HEVN is not a bank and holds no key to the wallet. Virtual accounts, fiat payins and fiat payouts are provided by partner banks, which hold fiat while it is in transit. Self-serve (the General tab): the person who controls the email signs for the wallet. Developers integrate /dapi/v1 in one of two ways. HEVN Connect (recommended, the HEVN Connect tab): the integrator's customer creates or links a HEVN account in a HEVN-hosted sign-in window on the integrator's site, the integrator's backend reads the linked account and books its payouts, and the account holder approves each payout in that window. External wallets (the External wallets tab, enabled per integrator): the integrator creates a client through the API, registers a wallet address the customer holds as an external account, and requests virtual accounts that deliver to that address. The customer's own wallet sends each transfer that funds a payout. The developer key signs for the integrator's wallet and its sub accounts and cannot sign for a client's wallet. > Use HEVN's terms as written. A product is the region a client requests. A rail is the bank route HEVN picks for the product. A virtual account (bnk_) is the record a partner bank opens for a client. Account details are what a payer needs to send a bank transfer, returned in a field named requisites. A client (cl_) is a customer's account: linked to the integrator through Sign in with HEVN (POST /dapi/v1/connect/sessions, then POST /dapi/v1/clients/link), or created with POST /dapi/v1/clients for an external-wallets integration. An external account (acc_, kind external) is a wallet address the client holds and signs for. A sub account (acc_, kind sub) is a further wallet of the integrator's own account on Base, spent with the developer key. Write 'sub account' as two words. A contact is a saved destination. A beneficiary is the party that receives a fiat payout. Money leaving an account is a payout, whether it goes to a bank account or to a wallet. > Do not name a bank, payment institution, card issuer, identity-verification vendor or stablecoin issuer. Say 'the partner bank'. Do not describe HEVN as licensed, regulated or insured. > HEVN publishes no fee rates, spreads or minimums. Prices come from a quote on a specific payment. Direct pricing questions to HEVN and do not invent numbers. > The API is at /dapi/v1 and takes a developer-key session plus an X-Hevn-Account header. Developer keys have an IP allowlist and no scopes. Remote transfers are at /api/v1/remote_spend_limit and take a remote transfer key (rsl_) in X-Api-Key, bounded by an onchain spend permission the account holder grants. The two credentials are separate and neither works on the other API. The HEVN CLI is discontinued. # List supported chains and tokens > Every chain and token this API names, with the contract address and decimals of each token. `settlement` marks the chain accounts hold their balance on and the tokens a payout can be funded with. ## OpenAPI ````yaml /openapi.json get /chains openapi: 3.1.0 info: title: HEVN Platform API description: >- HEVN's account, verification and money-movement API. Verification follows a submission workflow: save applicant info and documents, inspect outstanding requirements, then explicitly complete the submission to send an immutable snapshot for review. Completing a submission is separate from editing it. version: 1.0.0 servers: [] security: [] tags: - name: auth description: >- Log in with a developer key and refresh the access token. Developer keys are created in the HEVN app. - name: accounts description: Create and manage business or individual customer accounts. - name: client accounts description: >- Register addresses a client holds on supported networks, and open sub accounts of the client, to receive and pay USDC through. - name: verification description: >- Collect business-applicant and related-individual information, inspect requirements, and complete a verification submission for review. - name: documents description: Upload verification and payment evidence for later reference by id. - name: virtual accounts description: Discover payment methods and create persistent receiving account details. - name: transfers description: Quote, create, authorize and track incoming or outgoing transfers. - name: contacts description: Create saved contacts and inspect their available payment channels. - name: transactions description: Read and export the account ledger. - name: escrow description: Create, authorize and reconcile on-chain escrow agreements. - name: sandbox description: >- Emulate funding and lifecycle events in the sandbox. These routes return `404` in production. paths: /chains: get: tags: - catalog summary: List supported chains and tokens description: >- Every chain and token this API names, with the contract address and decimals of each token. `settlement` marks the chain accounts hold their balance on and the tokens a payout can be funded with. operationId: list_chains_chains_get responses: '200': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/ChainListView' '422': description: Request validation failed content: application/json: schema: $ref: '#/components/schemas/PlatformErrorResponse' security: - HTTPBearer: [] components: schemas: ChainListView: properties: chains: items: $ref: '#/components/schemas/ChainView' type: array title: Chains description: Every chain this API names, settlement chain included. type: object required: - chains title: ChainListView PlatformErrorResponse: properties: error: $ref: '#/components/schemas/PlatformErrorBody' description: Public error body. type: object required: - error title: PlatformErrorResponse ChainView: properties: chain: type: string title: Chain description: Chain code used by contacts, payouts and transactions. name: type: string title: Name description: Human-readable chain name. chainId: anyOf: - type: integer - type: 'null' title: Chainid description: EVM chain id; absent for non-EVM chains. settlement: type: boolean title: Settlement description: >- Whether payouts, payins and swaps settle on this chain. A token elsewhere may still name an account. tokens: items: $ref: '#/components/schemas/TokenView' type: array title: Tokens description: Tokens this API names on the chain. type: object required: - chain - name - settlement - tokens title: ChainView PlatformErrorBody: properties: code: $ref: '#/components/schemas/PlatformErrorCode' description: Stable machine-readable error code to branch on. message: type: string title: Message description: Human-readable explanation safe to show to an end user. details: anyOf: - additionalProperties: true type: object - type: 'null' title: Details description: >- Structured context for this error, with camelCase keys. `validation_failed` lists `fields`, plus `location` for a query, path or header. A `5xx` adds `requestId`. type: object required: - code - message title: PlatformErrorBody TokenView: properties: symbol: type: string title: Symbol description: Token symbol, as contacts and payouts name it. decimals: type: integer title: Decimals description: On-chain decimals of the token's smallest unit. address: anyOf: - type: string - type: 'null' title: Address description: ERC-20 contract address; absent for a chain's gas coin. native: type: boolean title: Native description: Whether this is the chain's gas coin. account: anyOf: - $ref: '#/components/schemas/AccountKey' - type: 'null' description: >- The account this token holds, when a client can hold a balance in it. type: object required: - symbol - decimals - native title: TokenView PlatformErrorCode: type: string enum: - invalid_request - validation_failed - invalid_cursor - invalid_id - idempotency_key_invalid - idempotency_key_reused - unauthenticated - token_expired - forbidden - not_found - method_not_allowed - conflict - gone - payload_too_large - rate_limited - provider_unavailable - database_unavailable - internal_error - invalid_credentials - request_expired - challenge_not_found - challenge_consumed - challenge_expired - signature_invalid - key_not_registered - signer_not_attached - wallet_not_linked - approval_consumed - approval_expired - approval_mismatch - signing_policy_refused - login_unavailable - login_mode_unavailable - developer_key_not_found - developer_key_already_exists - account_header_invalid - account_scope_conflict - account_not_found - account_forbidden - account_read_only - account_not_controlled - contact_not_found - quote_not_submitted - quote_not_fundable - funding_mode_unsupported - funding_token_unsupported - insufficient_funds - smart_wallet_not_deployed - wallet_owner_unverified - already_funded - payment_slot_consumed - funding_in_progress - funding_attempt_expired - contact_changed - user_operation_rejected - user_operation_unavailable - transfer_policy_denied - client_creation_not_enabled - client_not_found - link_code_invalid - link_code_expired - client_already_linked - redirect_uri_not_allowed - payout_not_awaiting_signature - verification_not_applicable - profile_locked - contact_not_payable - contact_chain_unsupported - contact_token_unsupported - contact_payment_details_invalid - amount_below_minimum - amount_above_maximum - amount_precision_unsupported - payout_not_found - payout_not_fundable - quote_expired - bundler_rejected - bundler_unavailable - contact_in_use - kyb_incomplete - kyb_documents_processing - kyb_roster_conflict - kyb_subject_conflict - document_not_found - document_type_unsupported - invalid_enum_value - entity_not_found - escrow_not_found - escrow_action_not_found - escrow_not_operated_by_you - escrow_state_changed - action_in_flight - simulation_failed - stale_nonce - amount_out_of_range - amount_not_allowed - window_closed - token_not_supported - receiver_not_a_client - rail_not_found - rail_not_available - payin_not_available - payin_expired - payin_not_found - transaction_not_found - account_unavailable - account_not_supported - swap_not_found - swap_route_unavailable - swap_not_confirmable - intent_not_signable - sandbox_amount_limit_exceeded - sandbox_faucet_balance_too_high - account_address_taken - account_address_refused - account_not_spendable - account_destination_unsupported - source_account_unsupported - account_funding_invalid - account_spend_forbidden - refund_address_required - safe_mode_required - account_archive_unsupported title: PlatformErrorCode AccountKey: type: string enum: - USDC - EURC - RD - USDC_ARB - FDIC_USD - FDIC_EUR - KYC_CARDS title: AccountKey securitySchemes: HTTPBearer: type: http scheme: bearer ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.