> ## Documentation Index > Fetch the complete documentation index at: https://docs.cbpayapp.com/llms.txt > Use this file to discover all available pages before exploring further. # Create a wallet link challenge > Creates a nonce challenge to link an external wallet (custody=client) to the account. The wallet owner signs the structured envelope with the chain-native standard (EIP-191 / TIP-191) and the signature is submitted to `POST /v1/wallet-links/verify`. ## OpenAPI ````yaml /openapi.yaml post /v1/wallet-links/challenges openapi: 3.1.0 info: title: CBPay API version: '2.62' description: | CBPay is a multi-currency payment platform: fiat payouts and collections across Latin America, internal transfers, on-chain funding and withdrawals, and KYC screening. Every account holds four independent virtual balances — USDT (the operating currency), USDC, BTC and GOLD (grams of fine gold) — convertible on demand with swaps. Payouts and service fees can be paid from any of the four balances (`PUT /v1/settlement` or per-payout `settlement_asset`), and payins can auto-convert to the asset of your choice (`default_payin_asset`). All amounts are decimal strings in each currency's precision (6 decimals for USDT/USDC/GOLD, 8 for BTC). Errors always return `{"error": "", "message": ""}`. servers: - url: https://api.qbank.cl/platform description: Live (production, real money) - url: https://cryptobank.qbank.cl/platform description: Test (sandbox, simulated money — pk_test_ keys) security: - bearerAuth: [] tags: - name: Receipts description: >- Branded PDF receipt per operation, with a public signed-QR authenticity check, receipt_url on every response/webhook and automatic email delivery on final states. - name: Authentication description: Register and log in account members. Sessions last 24 hours. - name: Account description: Profile, members and API keys of the calling account. - name: Balances description: Balances, movement history and FX rates. - name: Payouts description: >- Fiat dispersals debited from the settlement balance of your choice (USDT by default). - name: Payins description: >- Fiat top-ups (QR, transfers, dedicated accounts, pull collections, cards, checkout links) credited automatically — in USDT by default, or auto-converted to the settlement asset of your choice. - name: Checkout description: >- Universal checkout links (`POST /v1/payins` with `method: "checkout"`) and the public payment-page endpoints — multi-country fiat, crypto with an ephemeral wallet per link and direct CBPay payment, settled in the asset of your choice. - name: Stored cards description: >- Cards saved with the payer's explicit consent during a 3-D Secure payment (COF). List, revoke and charge them on demand (MIT) without asking for the card again. - name: Subscriptions description: >- Recurring charges on a stored card managed by the platform scheduler — daily, weekly, monthly or yearly, with pause/resume/cancel and automatic dunning. - name: Transfers description: >- Free internal transfers between CBPay accounts (person or company, any combination). - name: Contacts description: >- Per-account address book of beneficiaries (CBPay, bank and crypto destinations) with phone matching and auto-save on every send. - name: Swaps description: >- Instant conversion between the account's USDT, USDC, BTC and GOLD balances at the account's quoted rate. - name: Crypto description: On-chain funding and withdrawals (TRON, Ethereum and Bitcoin). - name: Segregated wallets description: >- On-chain wallets with their own balance (companies unlimited; persons 1 per network+asset pair) — create, import, send, export the private key and auto-forward. The balance lives on-chain, never in the ledger. - name: Signature proofs description: >- Cryptographic message signing with wallets (EIP-191 ETH/EVM, TIP-191 TRON) — create, list, get and revoke signature proofs with public verification. - name: Wallet links description: >- Link external wallets (custody=client) to your account by signing a nonce challenge — create challenges, verify signatures, list and revoke links. - name: QR Crypto POS description: >- Amount-bearing crypto QR charges for processors with physical POS terminals (company accounts): verified merchants, exclusive address + QR per charge, early payment detection, per-merchant reconciliation and refunds over the crypto withdrawal rail. - name: KYC / KYB description: >- Identity verification: KYC for persons, KYB for companies — your own onboarding and third-party verifications for company accounts. - name: AML screening description: >- Standalone AML screening of persons and companies against sanctions, PEP and adverse media lists, with rescreening, continuous monitoring and a downloadable PDF report. - name: Wallet screening description: >- AML risk assessment of blockchain addresses (sanctions, illicit-fund exposure) with a per-scan fee, plus free automatic protection on withdrawals and deposits. - name: Qscore description: >- API-first credit bureau. Issues complete credit reports with a 1-999 score (bands A-E, or SC when there is no data), reads the latest score of a subject and manages ARCO disputes. Chile first, with a country-agnostic design. Every issued report carries a public verification code. - name: Analytics - name: Webhooks description: Subscriptions to receive signed event notifications. - name: Status description: Service availability. - name: Banking description: >- Real bank accounts: receive, hold and send money over international banking rails. - name: Cards description: >- Virtual and physical cards that spend Just-In-Time from the balance of your choice (USDT, USDC, BTC or GOLD), with per-card spending limits. - name: Security (OTP) description: >- One-time verification codes over SMS/WhatsApp/email protecting sensitive actions, plus self-service 2FA preferences. Applies to user sessions only — API keys are exempt. - name: Passkeys description: >- Passwordless sign-in with the device's biometrics (Face ID, Touch ID, Windows Hello, security keys) via WebAuthn, authenticator apps (TOTP) with backup codes, and session/device management. - name: Social login description: >- Passwordless sign up and sign in with Google, Apple, Microsoft and Facebook via token exchange. The front end obtains the provider credential; the API verifies it and issues the CBPay session. - name: Real-time events description: >- Server-Sent Events stream with everything that happens in the account (or across the organization for admins), replay with `Last-Event-ID`, optional initial snapshot and a 90-day queryable history. paths: /v1/wallet-links/challenges: post: tags: - Wallet links summary: Create a wallet link challenge description: >- Creates a nonce challenge to link an external wallet (custody=client) to the account. The wallet owner signs the structured envelope with the chain-native standard (EIP-191 / TIP-191) and the signature is submitted to `POST /v1/wallet-links/verify`. operationId: createWalletLinkChallenge requestBody: required: true content: application/json: schema: type: object required: - chain - address properties: chain: type: string enum: - eth - tron address: type: string description: External wallet address (EVM hex or TRON base58). example: chain: eth address: '0x71C7656EC7ab88b098defB751B7401B5f6d8976F' responses: '201': description: Challenge created. content: application/json: schema: type: object properties: challenge: type: object properties: link_id: type: string format: uuid chain: type: string address: type: string nonce: type: string envelope: type: string description: >- The exact structured message (CBPay Signature Proof) the wallet owner must sign. expires_at: type: string format: date-time example: challenge: link_id: d52e7b91-4c68-4f89-1b23-5d7e9f0a2c46 chain: eth address: '0x71C7656EC7ab88b098defB751B7401B5f6d8976F' nonce: 9f2c41d2a887f3e4b219c6d2e8f1a5b7 envelope: |- CBPay Signature Proof Domain: https://api.qbank.cl/platform Purpose: wallet_link Wallet: 0x71C7656EC7ab88b098defB751B7401B5f6d8976F Account: ae8c1f02-3b45-4c67-9d12-8f0e5a6b7c8d Nonce: 9f2c41d2a887f3e4b219c6d2e8f1a5b7 Issued: 2026-08-21T14:03:11Z Expires: 2026-08-21T14:13:11Z expires_at: '2026-08-21T14:13:11Z' '400': description: >- Invalid request (`unsupported_chain`, `invalid_address`, `invalid_json`). content: application/json: schema: $ref: '#/components/schemas/Error' example: error: invalid_address message: the address is not valid for the chain '500': description: Nonce generation failed (`nonce_failed`). content: application/json: schema: $ref: '#/components/schemas/Error' example: error: nonce_failed message: could not generate the challenge nonce components: schemas: Error: type: object properties: error: type: string description: Machine-readable error code (snake_case). example: insufficient_funds message: type: string description: Human-readable explanation. securitySchemes: bearerAuth: type: http scheme: bearer description: | Session JWT (from register/login) or API key (`pk_...`). `X-API-Key: ` is accepted as an alternative header. ````