finch VS mint

We will use the Req library, a superset of Finch, which is itself a superset of Mint.

However, not every Elixir’s HTTP client supports sending requests using HTTP2 - so we have to search for another option rather than using HTTPoison that we widely use in other projects. We’ve decided to go with Finch, as apart from supporting HTTP2 it also focuses on performance and provides telemetry support out of the box - which we’ve found very useful for tracing and debugging purposes.

We will use the Req library, a superset of Finch, which is itself a superset of Mint.

One example is HTTP libraries.

For instance, take Mint (https://github.com/elixir-mint/mint):

> Mint is different from most Erlang and Elixir HTTP clients because it provides a process-less architecture.

Mint is a low-level library which doesn't make attempt to manage processes (including HTTP pooling).

In contrast, Finch (which builds on top of Mint) includes pool management:

https://github.com/elixir-mint/mint#connection-management-an...

It can take someone a bit off guard when they realise that the library they use provide a "default pool" they were not aware of, and that it can become a bottleneck etc.

> no error checking at all

Functions that raise always end in `!` in Elixir, or at least they should. Most have alternatives that return error tuples instead which you can pattern match on (this is what I recommend). You can read the docs for `get/2` (as opposed to `get!/2` which raises) here: https://hexdocs.pm/req/Req.html#get/2.

A common pattern is for the `!` version to call the version that doesn't raise, check the result, and raise on error, which is the case here: https://github.com/wojtekmach/req/blob/9de30de0df481ee557ccc...

> and if "body" is JSON, how do you even get the raw body, or can you?

You would set `decode: false` when calling `get!/2: https://hexdocs.pm/req/Req.html#new/1. You can also set this as configuration with https://hexdocs.pm/req/Req.html#default_options/1.

As a closing note I'll mention that Req is intended to be a very high-level, scripting-friendly requests library, similar to Requests in Python. If you don't want conveniences like Req provides, you can either turn them off or use something different, like Finch (which Req is based on, https://github.com/sneako/finch). Other than Req and Finch I'm personally only familiar with HTTPoison, which is significantly older than all of the libraries derived from Mint (like Finch and Req, https://github.com/elixir-mint/mint) but still works. There are many others though, like Gun and Tesla and such.