> ## Documentation Index > Fetch the complete documentation index at: https://docs.zapyd.com/llms.txt > Use this file to discover all available pages before exploring further. # Add Wallet > Adds a crypto wallet address to a customer, or updates it if it already exists. Wallets with a label form the customer's address book. Add the Zapyd "Add Wallet" call (`POST /cms/api/v1/customer/wallet/add`) to my backend. Adds a crypto wallet address to a customer, or updates it if it already exists. Wallets with a label form the customer's address book. * Sandbox: `POST https://sandbox.zapyd.com/cms/api/v1/customer/wallet/add` * Production: `POST https://api.zapyd.com/cms/api/v1/customer/wallet/add` JSON body: * `customer_id` (string, uuid, required): Customer's unique identifier. * `wallet_address` (string, required): Wallet address. Must match the network's address format (0x… for EVM networks, T… for Tron, base58 for Solana). Example: `0x1234567890123456789012345678901234567890`. * `network` (string, required): Blockchain network, case-insensitive: Ethereum, Polygon, Arbitrum, Bsc, Sepolia, Solana, Tron. Example: `Ethereum`. * `label` (string, optional): Optional label. Wallets with a label are shown in List Wallets (address book). Example: `Main wallet`. Success: HTTP 200, `{status: true, message, data}`. `data`: `id` (Wallet ID (integer). Use it in the fetch and delete paths), `wallet_address`, `network`, `label` (Label shown in the address book. Only labelled wallets are returned by List Wallets), `status`, `is_visible` (True when the wallet has a non-empty label), `created_at` (Creation time (ISO 8601)). Every endpoint can also return 401 `AUTH_*` (signature, timestamp or key: fix, don't retry), and 429 or 5xx (retry with backoff). Rules: * Saves a customer's own crypto address (an address book). Payin crypto doesn't go here: it goes to your organization's delivery wallet. * Re-adding an existing address for the customer updates it. The address must match the network's format (`0x…` EVM, `T…` Tron, base58 Solana). `Sepolia` is sandbox only. * Only wallets with a `label` appear in `GET /customer/wallet/list`. Save `data.id` (an integer) as `wallet_id`. Signing (every request): * Headers: `X-API-KEY`, `X-TIMESTAMP` (Unix seconds, within 300 s of server time; generate per request) and `X-SIGNATURE`. * `X-SIGNATURE` = Base64(HMAC-SHA256(key = API secret, message = apiKey + "|" + timestamp + "|" + canonicalBody)). Base64 of the raw digest, not hex. * canonicalBody: the JSON body with keys sorted at every nesting level, no whitespace (separators `,` and `:`), and every non-ASCII character escaped as lowercase `\uXXXX` (Python `json.dumps(body, sort_keys=True, separators=(",", ":"))`). Requests with no body (GET, DELETE) sign `{}`. Query parameters are not signed. * Send the exact canonicalBody string you signed as the request body, with `Content-Type: application/json`. * Test vector: key `3f1b2c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d`, secret `test-secret-do-not-use`, timestamp `1735689600`. Signing `{}` gives `6sCtVSRQjU9+2/af8gdwUAvY1l6Ii6ENcbRfanPkhY0=`. Body `{"customer_id":"78c99d71-f28f-47a9-8302-93b286efbe0e","amount":100.5,"currency":"INR","meta":{"note":"Café","b":2,"a":1}}` gives `l+DvQrzlKbsOSxSYOdWoWHEehcFRZfDJPKlLDkm2cSI=`. Deliver: 1. A typed `addWallet` function in this codebase's language and HTTP client. Reuse an existing Zapyd client and signer, or write one small shared client. 2. Config from `ZAPYD_API_KEY`, `ZAPYD_API_SECRET` and `ZAPYD_BASE_URL`. The secret stays on the server, never in a browser or app. 3. Return `data`. When `status` is false, throw an error with the HTTP status, `err_code`, `message` and `errors`. Don't show raw errors to end users. 4. Retry only 429 and 5xx: exponential backoff from 1 s, capped at 30 s, at most 5 attempts. 5. Amounts as strings. Types for every field above. 6. Tests: the signer against the test vector, and this call against sandbox. Reference: `https://docs.zapyd.com/api-reference-exchange/endpoint/wallet/add.md` ## OpenAPI ````yaml POST /customer/wallet/add openapi: 3.1.0 info: title: Zapyd API description: API for Zapyd - Customer, Payout, and Webhook services license: name: MIT version: 1.0.0 servers: - url: https://sandbox.zapyd.com/pos/api/v1 description: Payout API Base URL variables: base_url: default: https://sandbox.zapyd.com - url: https://sandbox.zapyd.com/cms/api/v1 description: Customer API Base URL variables: base_url: default: https://sandbox.zapyd.com security: - ApiKeyAuth: [] TimestampAuth: [] SignatureAuth: [] tags: - name: Customer description: Customer related operations x-displayName: Customer x-traitTag: true - name: Payout description: Payout related operations - name: Webhooks description: Webhook related operations - name: Widget description: Hosted buy/sell widget session initialization paths: /customer/wallet/add: post: tags: - Wallet description: >- Add a crypto wallet to a customer, or update it if the address already exists for that customer. `network` is matched case-insensitively and the address is validated against the network's format. Only wallets saved with a non-empty `label` appear in List Wallets. requestBody: required: true content: application/json: schema: type: object properties: customer_id: type: string description: Customer's unique identifier example: c2cf861b-342b-4318-a90e-85cd0312e82f format: uuid wallet_address: type: string description: >- Wallet address. Must match the network's address format (0x… for EVM networks, T… for Tron, base58 for Solana). example: '0x1234567890123456789012345678901234567890' network: type: string description: >- Blockchain network, case-insensitive: Ethereum, Polygon, Arbitrum, Bsc, Sepolia, Solana, Tron example: Ethereum label: type: string description: >- Optional label. Wallets with a label are shown in List Wallets (address book). example: Main wallet required: - customer_id - wallet_address - network responses: '200': description: Success content: application/json: schema: type: object properties: status: type: boolean example: true message: type: string example: Wallet added/updated successfully data: type: object properties: id: type: integer description: >- Wallet ID (integer). Use it in the fetch and delete paths. example: 42 wallet_address: type: string description: Wallet address example: '0x1234567890123456789012345678901234567890' network: type: string description: Canonical network name example: Ethereum enum: - Ethereum - Polygon - Arbitrum - Bsc - Sepolia - Solana - Tron label: type: string description: >- Label shown in the address book. Only labelled wallets are returned by List Wallets. example: Main wallet status: type: string description: Wallet status example: ACTIVE enum: - ACTIVE - INACTIVE is_visible: type: boolean description: True when the wallet has a non-empty label example: true created_at: type: string description: Creation time (ISO 8601) example: '2026-09-30T10:00:00Z' format: date-time '400': description: Bad Request content: application/json: schema: type: object properties: status: type: boolean example: false message: type: string example: Bad Request data: type: 'null' errors: type: object example: network: - This field is required. err_code: type: string example: REQ_FIELD_MISSING '500': description: Internal Server Error content: application/json: schema: type: object properties: status: type: boolean example: false message: type: string example: Internal Server Error data: type: 'null' errors: type: object example: {} err_code: type: string example: SYS_INTERNAL_ERROR servers: - url: https://sandbox.zapyd.com/cms/api/v1 description: Customer API Base URL components: securitySchemes: ApiKeyAuth: type: apiKey in: header name: X-API-KEY description: API Key for authentication TimestampAuth: type: apiKey in: header name: X-TIMESTAMP description: Current timestamp in seconds since epoch SignatureAuth: type: apiKey in: header name: X-SIGNATURE description: HMAC SHA256 signature of the request encoded in Base64 ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.