Convert Currency GET /api/Exchange/from={baseCurrencyCode}&to={targetCurrencyCode}&amount={amount}
curl "http://localhost:8080/api/Exchange/from=USD&to=EUR&amount=100"
Converts an amount from one currency to another using the current exchange rate.
Path Parameters Currency code to convert from (e.g., “USD”)
Currency code to convert to (e.g., “EUR”)
Amount to convert (must be a positive number)
Exchange Rate Resolution The API uses an intelligent exchange rate resolution system with three strategies:
Direct Rate : First attempts to find a direct exchange rate from base to target currencyReverse Rate : If no direct rate exists, calculates using the reverse rate (1 / rate) from target to baseCross Rate : If neither direct nor reverse rate exists, calculates using cross rates through intermediate currencies (e.g., USD→RUB→EUR)
Response Currency conversion result Source currency information Target currency information (same structure as baseCurrency)
Exchange rate used for conversion
Original amount in base currency
Converted amount in target currency
Example Response { "baseCurrency" : { "id" : 1 , "code" : "USD" , "fullName" : "United States Dollar" , "sign" : "$" }, "targetCurrency" : { "id" : 2 , "code" : "EUR" , "fullName" : "Euro" , "sign" : "€" }, "rate" : 0.92 , "amount" : 100.0 , "convertedAmount" : 92.0 }
Example Usage Convert USD to EUR: curl "http://localhost:8080/api/Exchange/from=USD&to=EUR&amount=100"
Convert EUR to GBP: curl "http://localhost:8080/api/Exchange/from=EUR&to=GBP&amount=50"
Convert with decimal amount: curl "http://localhost:8080/api/Exchange/from=USD&to=JPY&amount=99.99"
Conversion Logic The conversion follows this formula:
convertedAmount = amount × rate
For example:
Converting 100 USD to EUR with rate 0.92:
Error Responses Currency not found: { "type" : "https://tools.ietf.org/html/rfc7231#section-6.5.1" , "title" : "One or more validation errors occurred." , "status" : 400 , "errors" : { "message" : [ "Не удалось найти валюту" ] } }
No exchange rate available: { "type" : "https://tools.ietf.org/html/rfc7231#section-6.5.4" , "title" : "An error occurred while processing the request." , "status" : 500 , "errors" : { "message" : [ "Не удалось найти или создать подходящий обменный курс" ] } }
Invalid amount format: { "type" : "https://tools.ietf.org/html/rfc7231#section-6.5.1" , "title" : "One or more validation errors occurred." , "status" : 400 , "errors" : { "amount" : [ "The value 'invalid' is not valid for amount." ] } }
Multi-Currency Conversion Examples Simple Direct Conversion When a direct exchange rate exists between two currencies:
curl "http://localhost:8080/api/Exchange/from=USD&to=EUR&amount=250"
Response:
{ "baseCurrency" : { "id" : 1 , "code" : "USD" , "fullName" : "United States Dollar" , "sign" : "$" }, "targetCurrency" : { "id" : 2 , "code" : "EUR" , "fullName" : "Euro" , "sign" : "€" }, "rate" : 0.92 , "amount" : 250.0 , "convertedAmount" : 230.0 }
Reverse Rate Conversion When only the reverse rate exists (e.g., EUR→USD exists, but you need USD→EUR):
curl "http://localhost:8080/api/Exchange/from=EUR&to=USD&amount=100"
The system automatically calculates the reverse rate.
Cross Rate Conversion When no direct or reverse rate exists, the system uses intermediate currencies:
curl "http://localhost:8080/api/Exchange/from=GBP&to=JPY&amount=50"
The system might convert GBP→USD→JPY automatically.
Notes
All amounts are returned as floating-point numbers
Exchange rates may be automatically created and saved when using reverse or cross rate strategies
The API ensures currency codes exist before performing conversions
Validation errors include descriptive messages (some in Russian)