Create Conversion

curl -X POST "https://sandbox-api.tender.cash/v1/api/conversions" \
  -H "Content-Type: application/json" \
  -H "x-access-id: your-access-id-here" \
  -H "x-request-id: 550e8400-e29b-41d4-a716-446655440000" \
  -H "x-timestamp: 2026-10-15T09:45:53.000Z" \
  -H "authorization: <signature>" \
  -d '{"type":"crypto","chain":"ethereum","coin":"usdt","amount":"100","toChain":"solana","toCoin":"sol"}'

curl -X POST "https://sandbox-api.tender.cash/v1/api/conversions" \
  -H "Content-Type: application/json" \
  -H "x-access-id: your-access-id-here" \
  -H "x-request-id: 550e8400-e29b-41d4-a716-446655440000" \
  -H "x-timestamp: 2026-10-15T09:45:53.000Z" \
  -H "authorization: <signature>" \
  -d '{"type":"fiat","chain":"ethereum","coin":"usdt","amount":"100","payoutAccountId":"66aec7de809b7f45c42a49f9"}'

{
  "status": "success",
  "message": "Conversion created successfully",
  "data": {
    "conversion": {
      "conversionId": "66aec7de809b7f45c42a49f9",
      "amount": 100,
      "usdAmount": 100,
      "status": "pending",
      "destinationType": "crypto"
    }
  }
}

{
  "status": "error",
  "message": "Conversion request must be more than $20 USD",
  "data": {}
}

POST

api

conversions

curl -X POST "https://sandbox-api.tender.cash/v1/api/conversions" \
  -H "Content-Type: application/json" \
  -H "x-access-id: your-access-id-here" \
  -H "x-request-id: 550e8400-e29b-41d4-a716-446655440000" \
  -H "x-timestamp: 2026-10-15T09:45:53.000Z" \
  -H "authorization: <signature>" \
  -d '{"type":"crypto","chain":"ethereum","coin":"usdt","amount":"100","toChain":"solana","toCoin":"sol"}'

curl -X POST "https://sandbox-api.tender.cash/v1/api/conversions" \
  -H "Content-Type: application/json" \
  -H "x-access-id: your-access-id-here" \
  -H "x-request-id: 550e8400-e29b-41d4-a716-446655440000" \
  -H "x-timestamp: 2026-10-15T09:45:53.000Z" \
  -H "authorization: <signature>" \
  -d '{"type":"fiat","chain":"ethereum","coin":"usdt","amount":"100","payoutAccountId":"66aec7de809b7f45c42a49f9"}'

{
  "status": "success",
  "message": "Conversion created successfully",
  "data": {
    "conversion": {
      "conversionId": "66aec7de809b7f45c42a49f9",
      "amount": 100,
      "usdAmount": 100,
      "status": "pending",
      "destinationType": "crypto"
    }
  }
}

{
  "status": "error",
  "message": "Conversion request must be more than $20 USD",
  "data": {}
}

Auth method: Signed (HMAC) — this endpoint requires the full set of signed headers: x-access-id, x-request-id, x-timestamp, and an HMAC-SHA256 authorization signature. See Authentication.

All conversion endpoints share a bucket of 10 requests per minute per merchant, on top of the general limit. See Rate limits. There are two conversion types:

crypto swaps coin on chain into toCoin on toChain. The result always settles to your own merchant wallet on toChain.
fiat converts coin on chain and sends the result to one of your saved, active payout accounts (payoutAccountId). If that payout account is a bank account, the funds are paid out in its fiat currency; if it is a crypto account, they are sent to its address on its chain and coin.

Tender picks the conversion route automatically; you can’t choose a provider. The conversion is created with status pending and processed asynchronously. There are no conversion webhooks: poll Get Conversion until status is completed or failed. The conversion must be worth more than $20 USD. Call Calculate Conversion Fee first to show the fee and the expected output.

Headers

string

required

Base64-encoded HMAC-SHA256 signature of {"timeStamp":"<x-timestamp>","requestId":"<x-request-id>","accessId":"<x-access-id>"}, signed with your access secret. The request body is not part of the signature.Example: "pV3n0o8kq0lK2mJ8bZ1yq3Yt6hR0cXK9u4mVJ2l9sE0="

string

required

ISO 8601 timestamp; must be within 5 minutes of server timeExample: "2026-10-15T09:45:53.000Z"

string

required

A unique UUID v4 per requestExample: "550e8400-e29b-41d4-a716-446655440000"

string

required

Your API access ID provided by TenderExample: "your-access-id-here"

string

required

Must be application/jsonExample: "application/json"

Body

string

required

Conversion type.Allowed values: crypto, fiatExample: "crypto"

string

required

Source chain IDExample: "ethereum"

string

required

Source coin IDExample: "usdt"

string

required

Amount to convert, in the source coin. Must be sent as a string.Example: "100"

string

Destination chain ID. Required when type is crypto.Example: "solana"

string

Destination coin ID. Required when type is crypto.Example: "sol"

string

ID of one of your active payout accounts. Required when type is fiat.Example: "66aec7de809b7f45c42a49f9"

Response

string

required

Example: "success"

string

required

Example: "Conversion created successfully"

object

required

Show data properties

object

Summary of the new conversion

Show conversion properties

string

Conversion ID. Use it with Get Conversion.Example: "66aec7de809b7f45c42a49f9"

number

Source amountExample: 100

number

Source amount in USDExample: 100

string

Always pending on creationExample: "pending"

string

crypto or fiat. For type: "fiat", this is the type of the payout account.Example: "crypto"

Errors

HTTP	Message	Cause
400	`Invalid chain reference` / `Invalid currency reference`	Unknown source `chain` or `coin`
400	`Invalid to chain reference` / `Invalid to currency reference`	Unknown `toChain` or `toCoin` (`crypto`)
400	`Merchant wallet not found`	You have no merchant wallet on `toChain` (`crypto`)
400	`Currency is not enabled for swap`	The source coin can’t be converted (`fiat`)
400	`Invalid or inactive payout account`	`payoutAccountId` is not one of your active payout accounts (`fiat`)
400	`Conversion request must be more than $20 USD`	The amount is worth $20 or less
400	Validation message, e.g. `toChain must be a string`	A required field is missing or has the wrong type
500	`Failed to create conversion`	The conversion could not be priced or created. Check the pair with the fee endpoint and retry.

curl -X POST "https://sandbox-api.tender.cash/v1/api/conversions" \
  -H "Content-Type: application/json" \
  -H "x-access-id: your-access-id-here" \
  -H "x-request-id: 550e8400-e29b-41d4-a716-446655440000" \
  -H "x-timestamp: 2026-10-15T09:45:53.000Z" \
  -H "authorization: <signature>" \
  -d '{"type":"crypto","chain":"ethereum","coin":"usdt","amount":"100","toChain":"solana","toCoin":"sol"}'

curl -X POST "https://sandbox-api.tender.cash/v1/api/conversions" \
  -H "Content-Type: application/json" \
  -H "x-access-id: your-access-id-here" \
  -H "x-request-id: 550e8400-e29b-41d4-a716-446655440000" \
  -H "x-timestamp: 2026-10-15T09:45:53.000Z" \
  -H "authorization: <signature>" \
  -d '{"type":"fiat","chain":"ethereum","coin":"usdt","amount":"100","payoutAccountId":"66aec7de809b7f45c42a49f9"}'

{
  "status": "success",
  "message": "Conversion created successfully",
  "data": {
    "conversion": {
      "conversionId": "66aec7de809b7f45c42a49f9",
      "amount": 100,
      "usdAmount": 100,
      "status": "pending",
      "destinationType": "crypto"
    }
  }
}

{
  "status": "error",
  "message": "Conversion request must be more than $20 USD",
  "data": {}
}

Authorizations

authorization

string

header

required

Signed (HMAC) authentication. Required headers: x-access-id, x-request-id (UUID v4), x-timestamp (ISO 8601, must be within 5 minutes of server time), and authorization: the Base64 HMAC-SHA256 of the JSON string {"timeStamp":"","requestId":"","accessId":""} (keys in that order, no whitespace) using your access secret. The request body, method and path are not signed. The API key must be linked to an outlet.

Headers

authorization

string

required

x-timestamp

string<date-time>

required

ISO 8601 timestamp; must be within 5 minutes of server time

x-request-id

string<uuid>

required

A unique UUID v4 per request

x-access-id

string

required

Content-Type

enum<string>

required

Available options:

application/json

Body

application/json

type

enum<string>

required

Available options:

crypto,

fiat

chain

string

required

Maximum string length: 500

Example:

"ethereum"

coin

string

required

Maximum string length: 500

Example:

"usdt"

amount

string

required

Amount in the source coin, as a string. Must be worth more than $20 USD.

Maximum string length: 500

Example:

"100"

toChain

string

Required when type is crypto

Maximum string length: 500

Example:

"solana"

toCoin

string

Required when type is crypto

Maximum string length: 500

Example:

"sol"

payoutAccountId

string

Required when type is fiat. One of your active payout accounts.

Response

Conversion created

status

string

required

Example:

"success"

message

string

required

Example:

"success"

data

object

required

Show child attributes

Payment

System

Agents

Conversions

Payouts

Subwallets

Webhooks

On-ramp

Headers

Body

Response

Errors

Authorizations

Headers

Body

Response

​Headers

​Body

​Response

​Errors

Authorizations

Headers

Body

Response

Headers

Body

Response

Errors