Calculate Conversion Fee

curl "https://sandbox-api.tender.cash/v1/api/conversions/fee/ethereum/usdt/100?toChain=solana&toCoin=sol" \
  -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>"

curl "https://sandbox-api.tender.cash/v1/api/conversions/fee/ethereum/usdt/100?toChain=fiat&toCoin=ngn" \
  -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>"

{
  "status": "success",
  "message": "success",
  "data": {
    "from": { "chain": "ethereum", "currency": "usdt", "symbol": "USDT", "amount": 100, "amountUSD": 100 },
    "to": { "chain": "solana", "currency": "sol", "symbol": "SOL", "amount": 0.6633, "amountUSD": 99.5 },
    "fee": { "fee": 0.5, "feeUSD": 0.5 },
    "rate": { "value": "0.006667", "perSourceUnit": "0.006700", "symbol": "SOL", "overridden": false }
  }
}

{
  "status": "error",
  "message": "Invalid destination currency",
  "data": {}
}

GET

api

conversions

fee

{chain}

{coin}

{amount}

curl "https://sandbox-api.tender.cash/v1/api/conversions/fee/ethereum/usdt/100?toChain=solana&toCoin=sol" \
  -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>"

curl "https://sandbox-api.tender.cash/v1/api/conversions/fee/ethereum/usdt/100?toChain=fiat&toCoin=ngn" \
  -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>"

{
  "status": "success",
  "message": "success",
  "data": {
    "from": { "chain": "ethereum", "currency": "usdt", "symbol": "USDT", "amount": 100, "amountUSD": 100 },
    "to": { "chain": "solana", "currency": "sol", "symbol": "SOL", "amount": 0.6633, "amountUSD": 99.5 },
    "fee": { "fee": 0.5, "feeUSD": 0.5 },
    "rate": { "value": "0.006667", "perSourceUnit": "0.006700", "symbol": "SOL", "overridden": false }
  }
}

{
  "status": "error",
  "message": "Invalid destination currency",
  "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. The quote is an estimate at current prices. The final figures are fixed when you create the conversion.

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"

Path parameters

string

required

Source chain IDExample: "ethereum"

string

required

Source coin ID (for example usdt, not the symbol USDT)Example: "usdt"

string

required

Amount to convert, in the source coin. Must be greater than zero.Example: "100"

Query parameters

string

Destination chain ID for a crypto swap. Use fiat to quote a fiat conversion.Example: "solana"

string

Destination coin ID for a crypto swap, or a fiat currency ID (for example ngn) when toChain is fiat. If omitted, the destination is the source coin.Example: "sol"

Response

string

required

success on successExample: "success"

string

required

Human-readable result messageExample: "success"

object

required

Conversion quote

Show data properties

object

Source side of the quote

Show from properties

string

Example: "ethereum"

string

Example: "usdt"

string

Example: "USDT"

number

Amount you convertExample: 100

number

USD value of amountExample: 100

object

Destination side of the quote, after fees

Show to properties

string

Destination chain, fiat for fiat quotes. Absent when you don’t send toChain.Example: "solana"

string

Example: "sol"

string

Example: "SOL"

number

Estimated amount you receive, in the destination currencyExample: 0.6633

number

USD value after the feeExample: 99.5

object

Conversion fee

Show fee properties

number

Fee in the source coinExample: 0.5

number

Fee in USDExample: 0.5

object

Exchange rate

Show rate properties

string

Destination units per USD, after fees. Two decimals for fiat, six for crypto.Example: "0.006667"

string

Value of one source unit in the destination currency, before fees. Use it to display “1 from.symbol = perSourceUnit rate.symbol”.Example: "0.006700"

string

Destination symbolExample: "SOL"

boolean

true if the quote uses a fixed rate instead of the live market rateExample: false

Errors

All return HTTP 400.

Message	Cause
`Amount must be greater than zero`	`amount` is zero, negative or not a number
`Invalid chain`	Unknown source chain
`Invalid currency`	Unknown source coin
`Exchange price not available`	No price for the source coin
`Invalid destination chain`	Unknown `toChain`
`Invalid destination currency`	Unknown `toCoin`
`Exchange price not available for destination currency`	No price for `toCoin`
`Invalid destination exchange rate`	The destination price is unusable

curl "https://sandbox-api.tender.cash/v1/api/conversions/fee/ethereum/usdt/100?toChain=solana&toCoin=sol" \
  -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>"

curl "https://sandbox-api.tender.cash/v1/api/conversions/fee/ethereum/usdt/100?toChain=fiat&toCoin=ngn" \
  -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>"

{
  "status": "success",
  "message": "success",
  "data": {
    "from": { "chain": "ethereum", "currency": "usdt", "symbol": "USDT", "amount": 100, "amountUSD": 100 },
    "to": { "chain": "solana", "currency": "sol", "symbol": "SOL", "amount": 0.6633, "amountUSD": 99.5 },
    "fee": { "fee": 0.5, "feeUSD": 0.5 },
    "rate": { "value": "0.006667", "perSourceUnit": "0.006700", "symbol": "SOL", "overridden": false }
  }
}

{
  "status": "error",
  "message": "Invalid destination currency",
  "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

Path Parameters

chain

string

required

Source chain ID

coin

string

required

Source coin ID

amount

string

required

Amount in the source coin; must be greater than zero

Query Parameters

toChain

string

Destination chain ID, or fiat

toCoin

string

Destination coin ID, or fiat currency ID when toChain is fiat

Response

Quote

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

Path parameters

Query parameters

Response

Errors

Authorizations

Headers

Path Parameters

Query Parameters

Response

​Headers

​Path parameters

​Query parameters

​Response

​Errors

Authorizations

Headers

Path Parameters

Query Parameters

Response

Headers

Path parameters

Query parameters

Response

Errors