Fee Provider Docs (#1641)

docs/fee-provider/fee-provider.md

@@ -0,0 +1,21 @@
+---
+id: fee-provider
+title: Fee Provider
+---
+
+# Fee Provider
+
+Bitcoin-S has a `FeeProvider` that is used to fetch fee rates.
+Currently, Bitcoin-s has a couple implemented, one being a `BitcoindRpcClient`, which will use `estimateSmartFee` to calculate a fee rate.
+Another uses [bitcoiner.live's api](https://bitcoiner.live/) to get a fee rate.
+
+Any `FeeProvider` can be passed to a `Wallet` which will be used to calculate fees for transactions when one is not specified.
+
+## HttpFeeRateProvider
+
+A `HttpFeeRateProvider` is a `FeeProvider` that uses an outside API to get fee rates.
+These can be hooked up to any website's API as long as you can provide a `URI` and a function to convert the response to a `FeeUnit`.
+
+There also exists `CachedHttpFeeRateProvider`, which will cache the response for the `cacheDuration` as to prevent hitting request limits and save on api calls.
+
+Checkout [`BitcoinerLiveFeeRateProvider`'s implementation](https://github.com/bitcoin-s/bitcoin-s/blob/master/fee-provider/src/main/scala/org/bitcoins/feeprovider/BitcoinerLiveFeeRateProvider.scala) for an example.

website/sidebars.json

@@ -28,6 +28,9 @@
       "crypto/crypto-intro",
       "crypto/sign"
     ],
+    "Fee Provider": [
+      "fee-provider/fee-provider"
+    ],
     "Key Manager": [
       "key-manager/key-manager"
     ],