Select a conversion rate API

[mauriciovieira]

We are going to use some currency conversion rate API behind the scenes. As the bot will be free, the API must be free. It can be rate-limited, for instance, but nobody is going to pay for its use.

Please research the alternatives and write them as comments of this issue. Try to highlight pros and cons for each alternative.

[elvisserrao]

• exchangerate-api

  • It’s free (rate-limited)
  • 2.000 API Calls/month (around 11 requests every 4 hours)
  • Daily updated data
  • No authentication provided

[elvisserrao]

• rates-api

  • It’s free
  • Daily updated data
  • Offers Historical data since 1999.
  • It's built mostly on Python/JS.
  • No authentication provided

[elvisserrao]

• frankfurter

  • It’s free
  • Daily updated data
  • Offers Historical data since 1999.
  • It's built mostly on Ruby.
  • It can be self-hosted (https://www.frankfurter.app/docs/#deployment)
  • No authentication provided

[elvisserrao]

• fixer.io

  • It’s free (rate-limited)
  • 1.000 API Calls/month (around 11 requests every 8 hours)
  • Hourly updated data
  • Authentication with apiKey

[BrunBrand]

• Exchange Rates Api

  Free
  600 calls per month (reasonable) and 20 per day (ugh)
  Has 27 currencies
  Authentication via API key

[BrunBrand]

• Open Exchange Rates

  Has a free plan
  1000 calls per month
  Hourly updates
  Base currency is USD
  Authentication via API id (key)

[mauriciovieira]

We can think about one architectur with fallbacks if one API does not work. But out of all those alternatives, the more attractive is frankfurter. What do you think?

[BrunBrand]

Unfortunately doesn't have cryptocurrencies, but that is just a small minus should I say.
We could use two APIs, one to display the European central bank data as frankfurter and rates-api states, and another one to display cryptocurrencies.