Ruby Exchange Rate API

Quick Start

Fetch your first exchange rate using Ruby's standard library. No gems required.

require 'net/http'
require 'json'

uri = URI("https://exchange-rateapi.com/api/v1/rates?source=USD&target=EUR")
req = Net::HTTP::Get.new(uri)
req["Authorization"] = "Bearer era_live_YOUR_API_KEY"

res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |http|
  http.request(req)
}

data = JSON.parse(res.body)
puts "1 USD = #{data[0]['rate']} EUR"
# Output: 1 USD = 0.9215 EUR

Complete Ruby Example

Here is a production-ready example with a reusable client class, error handling, and support for multiple targets.

require 'net/http'
require 'json'
require 'uri'

class ExchangeRateClient
  BASE_URL = "https://exchange-rateapi.com/api/v1/rates"

  def initialize(api_key)
    @api_key = api_key
  end

  def get_rates(source, target)
    uri = URI("#{BASE_URL}?source=#{source}&target=#{target}")
    req = Net::HTTP::Get.new(uri)
    req["Authorization"] = "Bearer #{@api_key}"

    res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true,
                          open_timeout: 5, read_timeout: 10) { |http|
      http.request(req)
    }

    case res.code.to_i
    when 200
      JSON.parse(res.body)
    when 401
      raise "Invalid API key. Check your Authorization header."
    when 429
      raise "Rate limit exceeded. Try again later."
    else
      raise "HTTP #{res.code}: #{res.message}"
    end
  end
end

# Usage
client = ExchangeRateClient.new("era_live_YOUR_API_KEY")

# Single pair
rates = client.get_rates("USD", "EUR")
puts "1 USD = #{rates[0]['rate']} EUR"

# Multiple targets
rates = client.get_rates("USD", "EUR,GBP,JPY")
rates.each do |r|
  puts "1 USD = #{r['rate']} #{r['target']}"
end
# Output:
# 1 USD = 0.9215 EUR
# 1 USD = 0.7891 GBP
# 1 USD = 151.42 JPY

Using with HTTParty (Optional)

gem install httparty

require 'httparty'

response = HTTParty.get(
  "https://exchange-rateapi.com/api/v1/rates",
  query: { source: "USD", target: "EUR" },
  headers: { "Authorization" => "Bearer era_live_YOUR_API_KEY" }
)

data = response.parsed_response
puts "1 USD = #{data[0]['rate']} EUR"

Without Class (Quick Script)

For a quick one-off script, you can call the API in just a few lines.

require 'net/http'
require 'json'

uri = URI("https://exchange-rateapi.com/api/v1/rates?source=USD&target=EUR")
req = Net::HTTP::Get.new(uri)
req["Authorization"] = "Bearer era_live_YOUR_API_KEY"

res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |http|
  http.request(req)
}

data = JSON.parse(res.body)
puts data

Response Format

[
  {
    "rate": 0.9215,
    "source": "USD",
    "target": "EUR",
    "time": "2026-05-15T12:00:00Z"
  }
]

[
  { "rate": 0.9215, "source": "USD", "target": "EUR", "time": "2026-05-15T12:00:00Z" },
  { "rate": 0.7891, "source": "USD", "target": "GBP", "time": "2026-05-15T12:00:00Z" },
  { "rate": 151.42, "source": "USD", "target": "JPY", "time": "2026-05-15T12:00:00Z" }
]