> ## Documentation Index > Fetch the complete documentation index at: https://docs.payments.sardine.ai/llms.txt > Use this file to discover all available pages before exploring further. # Post Client Token > Exchange your `clientId` and `clientSecret` for a `clientToken` that can be be used in frontend code. `clientToken` will be unusable after the `expiresAt` time, which will normally be after 30 min. To try the request in the mock server on the right, substitute username for clientId and password for clientSecre ## OpenAPI ````yaml /api_reference/nft.yaml post /auth/client-tokens openapi: 3.1.0 info: version: '1.0' title: NFT API summary: API to enable direct NFT purchasing description: Reference for Sardine Crypto API servers: - url: https://api.sandbox.sardine.ai/v1 description: Sandbox - url: https://api.sardine.ai/v1 description: Prod Server security: - {} paths: /auth/client-tokens: post: summary: Post Client Token description: >- Exchange your `clientId` and `clientSecret` for a `clientToken` that can be be used in frontend code. `clientToken` will be unusable after the `expiresAt` time, which will normally be after 30 min. To try the request in the mock server on the right, substitute username for clientId and password for clientSecre operationId: post-crypto-auth-client_session_token requestBody: description: '' content: application/json: schema: type: object properties: referenceId: type: string description: Unique ID for an order format: uuid expiresIn: type: number description: Time, in seconds, after which this Order will expire maximum: 3600 examples: - 60 externalUserId: type: string description: >- A unique ID that represents a user or customer. This can be used if you wish to track orders on a per customer basis format: uuid nft: type: object required: - name - imageUrl properties: name: type: string description: Name of NFT imageUrl: type: string description: URL where image of the NFT can be retrieved from format: uri price: type: number description: Cost of the NFT in `currencyCode` format: float minimum: 0 executionType: x-stoplight: id: o949rg293xde1 enum: - smart_contract network: type: string x-stoplight: id: 8s1vzwgs8ccji example: polygon recipientAddress: type: string x-stoplight: id: a4ic9fhftejq6 example: '0x942D5A8BaC9684a3Fc1150b3cBbf931f32bBa514' platform: x-stoplight: id: r3ksrs2amvgc5 enum: - niftyswap - sequence_market - ERC8000 - '' contractAddress: type: string x-stoplight: id: pb6ylyj8k3oz8 example: '0x8bb759bb68995343ff1e9d57ac85ff5c5fb79334' blockchainNftId: type: string x-stoplight: id: 351snwicrti0o quantity: type: integer description: Quantity of the good being purchased currencyCode: const: usd description: 'Fiat currency this NFT is priced in. ' taxRates: type: object description: >- Which contains rates for countries/regions in ISO3166-2 format. properties: US-NY: type: string description: >- countrycode-subdivisions like US-NY. "US-NY": 13 means 13% for NY state. examples: - US-NY = 13 US: type: string description: >- Countrycode like US. It's percentage, US: 10 means 10% tax for all US examples: - US = 10 US-CA: type: string description: >- countrycode-subdivisions like US-CA. "US-CA": 20 means 20% for CA state. examples: - US-CA = 20 identityPrefill: type: object description: >- If fields here are passed, they will be pre filled in the Checkout properties: firstName: type: string description: First name of customer lastName: type: string description: Last name of customer dateOfBirth: type: string description: Date of birth in YYYY-MM-DD format: date emailAddress: type: string description: Email address of user format: email phone: type: string description: Phone number of user with country code address: type: object properties: street1: type: string street2: type: string city: type: string regionCode: type: string postalCode: type: string countryCode: type: string examples: example-1: value: referenceId: 42eadcb0-4a93-45af-9c8c-d295db5aeb6c customerId: adf02ae2-f633-11ec-b939-0242ac120002 nft: name: 'NFT #1' price: 100 currencyCode: USD imageUrl: >- https://gateway.nftcompany.io/ipfsQmSAQm4gbhjSeUk7fuYppHd7Z8dfWpBvnFmqFSKqkrUJPM identityPrefill: firstName: John lastName: Doe dateOfBirth: '2000-01-01' emailAddress: foobar@gmail.com phone: '+19254485826' address: street1: 123 Main st street2: '' city: irvine regionCode: CA postalCode: '02747' countryCode: US taxRates: US: 10 US-CA: 20 example-2: value: nft: name: The BEST NFT FOR DEMO PURPOSE NEW NFT price: 100 currencyCode: CAD contractAddress: '0x7fC0344254E1663C2eF24e3c063cbec231525C20' imageUrl: >- https://gateway.autograph.io/ipfs/QmSAQm4gbhjSeUk7fuYppHd7Z8dfWpBvnFmqFSKqkrUJPM taxRates: US: 10 US-CA: 20 US-NY: 13 Smart contract execution: value: referenceId: test-0.24678085734dwedwedwed04dwedfwrferfwedwed6884 expiresIn: 3600 identityPrefill: firstName: fname lastName: lname dateOfBirth: '2000-01-01' emailAddress: ethan.itovitch@allow.com phone: '+19923793139' address: street1: 123 main st street2: '' city: irvine regionCode: CA postalCode: '02747' countryCode: US paymentMethodTypeConfig: enabled: - us_debit - us_credit - international_debit - international_credit - ach default: us_debit nft: name: Hot wheels <> Sardine imageUrl: >- https://cdn.shopify.com/s/files/1/0568/1132/3597/files/HWNFT_S4_modular-grid_584x800b.jpg?v=1669157307 network: polygon recipientAddress: '0x942D5A8BaC9684a3Fc1150b3cBbf931f32bBa514' platform: niftyswap blockchainNftId: '131111' contractAddress: '0x8bb759bb68995343ff1e9d57ac85ff5c5fb79334' executionType: smart_contract quantity: 1 responses: '200': description: OK content: application/json: schema: type: object properties: clientToken: type: string description: Unique token that is used to authenticate the merchant format: uuid expiresAt: type: string description: Time at which the order will expire format: date-time examples: example-1: value: clientToken: 8aeae330-9154-4051-ab98-d173ba2bc7f0 '400': description: Bad Request content: application/json: schema: type: object properties: code: type: string description: Set to `false` if exchange is unsuccessful message: type: string description: >- Contains message describing what error occured during exchange examples: Error: value: code: UNAUTHORIZED message: Invalid client credentials security: - ClientToken: [] servers: - url: https://api.sandbox.sardine.ai/v1 description: Sandbox - url: https://api.sardine.ai/v1 description: Prod Server components: securitySchemes: ClientToken: type: http scheme: basic ````