diff --git a/backend/src/__tests__/api/fee-api.ts b/backend/src/__tests__/api/fee-api.ts
new file mode 100644
index 000000000..64f80bca9
--- /dev/null
+++ b/backend/src/__tests__/api/fee-api.ts
@@ -0,0 +1,55 @@
+import feeApi from '../../api/fee-api';
+import { IBitcoinApi } from '../../api/bitcoin/bitcoin-api.interface';
+const feeMempoolBlocks = require('./test-data/fee-mempool-blocks.json');
+
+
+const subSatMempoolInfo: IBitcoinApi.MempoolInfo = {
+  mempoolminfee: 0.000001, // 0.1 sat/vbyte
+  loaded: true,
+  size: 100,
+  bytes: 10000,
+  usage: 10000,
+  total_fee: 10000,
+  maxmempool: 10000,
+  minrelaytxfee: 0.000001, // 0.1 sat/vbyte
+};
+
+const mempoolInfo: IBitcoinApi.MempoolInfo = {
+  mempoolminfee: 0.00001,
+  loaded: true,
+  size: 100,
+  bytes: 10000,
+  usage: 10000,
+  total_fee: 10000,
+  maxmempool: 10000,
+  minrelaytxfee: 0.00001,
+};
+
+describe('Fee API', () => {
+  test('should calculate recommended fees properly for sub-sat mempool', () => {
+    const fee = feeApi.calculateRecommendedFee(feeMempoolBlocks.subsat, subSatMempoolInfo);
+    expect(fee.fastestFee).toBe(2);
+    expect(fee.halfHourFee).toBe(1);
+    expect(fee.hourFee).toBe(1);
+    expect(fee.economyFee).toBe(1);
+    expect(fee.minimumFee).toBe(1);
+  });
+
+  test('should calculate recommended fees properly for full but low fee mempool', () => {
+    const fee = feeApi.calculateRecommendedFee(feeMempoolBlocks.lowfee, mempoolInfo);
+    expect(fee.fastestFee).toBe(2);
+    expect(fee.halfHourFee).toBe(2);
+    expect(fee.hourFee).toBe(2);
+    expect(fee.economyFee).toBe(2);
+    expect(fee.minimumFee).toBe(1);
+  });
+
+  test('should calculate recommended fees properly for empty mempool', () => {
+    const fee = feeApi.calculateRecommendedFee(feeMempoolBlocks.empty, mempoolInfo);
+    expect(fee.fastestFee).toBe(1);
+    expect(fee.halfHourFee).toBe(1);
+    expect(fee.hourFee).toBe(1);
+    expect(fee.economyFee).toBe(1);
+    expect(fee.minimumFee).toBe(1);
+  });
+});
\ No newline at end of file
diff --git a/backend/src/__tests__/api/test-data/fee-mempool-blocks.json b/backend/src/__tests__/api/test-data/fee-mempool-blocks.json
new file mode 100644
index 000000000..f5a2efb20
--- /dev/null
+++ b/backend/src/__tests__/api/test-data/fee-mempool-blocks.json
@@ -0,0 +1,289 @@
+{
+  "subsat": [
+    {
+      "blockSize": 1746106,
+      "blockVSize": 997953.25,
+      "nTx": 3750,
+      "totalFees": 1764766,
+      "medianFee": 1.0023586640951265,
+      "feeRange": [
+        0.6082474226804123,
+        0.6082474226804123,
+        0.6082474226804123,
+        0.6082474226804123,
+        1.2076788830715532,
+        3.166077738515901,
+        73.61111111111111
+      ]
+    },
+    {
+      "blockSize": 1809871,
+      "blockVSize": 997963,
+      "nTx": 4861,
+      "totalFees": 588436,
+      "medianFee": 0.6082474226804123,
+      "feeRange": [
+        0.5156626506024097,
+        0.5649475055559813,
+        0.5670103092783505,
+        0.6082474226804123,
+        0.6082474226804123,
+        0.6082474226804123,
+        0.6082474226804123
+      ]
+    },
+    {
+      "blockSize": 2917870,
+      "blockVSize": 997821.25,
+      "nTx": 1221,
+      "totalFees": 535389,
+      "medianFee": 0.5200034509958588,
+      "feeRange": [
+        0.35051546391752575,
+        0.5649475055559813,
+        0.5649475055559813,
+        0.5649475055559813,
+        0.5649475055559813,
+        0.5649475055559813,
+        0.5649475055559813
+      ]
+    },
+    {
+      "blockSize": 3937966,
+      "blockVSize": 997875.25,
+      "nTx": 18,
+      "totalFees": 506205,
+      "medianFee": 0.5100003123470801,
+      "feeRange": [
+        0.35051546391752575,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.5099980684971892,
+        0.5100003123470801,
+        0.5100020185186144,
+        0.5100025244589157
+      ]
+    },
+    {
+      "blockSize": 3917639,
+      "blockVSize": 997810.25,
+      "nTx": 62,
+      "totalFees": 503529,
+      "medianFee": 0.5099975959779666,
+      "feeRange": [
+        0.35051546391752575,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.5099971889756266,
+        0.5100002265056967
+      ]
+    },
+    {
+      "blockSize": 3694897,
+      "blockVSize": 997893.25,
+      "nTx": 43,
+      "totalFees": 503307,
+      "medianFee": 0.5099952023028946,
+      "feeRange": [
+        0.35051546391752575,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.3704911425797351,
+        0.5099952023028946,
+        0.5099967157103613
+      ]
+    },
+    {
+      "blockSize": 2486759,
+      "blockVSize": 997857.5,
+      "nTx": 498,
+      "totalFees": 386911,
+      "medianFee": 0.36001120750903104,
+      "feeRange": [
+        0.35051546391752575,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.5000054632270189
+      ]
+    },
+    {
+      "blockSize": 6681226,
+      "blockVSize": 3385616.5,
+      "nTx": 10222,
+      "totalFees": 1197838,
+      "medianFee": 0.35051546391752575,
+      "feeRange": [
+        0.21576460085542437,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.35051546391752575,
+        0.3599967979827291,
+        0.3600004002561639,
+        0.3600040026016911,
+        0.3600040026016911,
+        0.3600040026016911
+      ]
+    }
+  ],
+
+  "empty": [{
+      "blockSize": 10000,
+      "blockVSize": 10000,
+      "nTx": 2000,
+      "totalFees": 1197838,
+      "medianFee": 1,
+      "feeRange": [
+        1,
+        1,
+        1,
+        1,
+        1,
+        1,
+        1
+      ]
+    }
+  ],
+
+  "lowfee": [
+    {
+      "blockSize": 1746106,
+      "blockVSize": 997953.25,
+      "nTx": 3750,
+      "totalFees": 1764766,
+      "medianFee": 1.0023586640951265,
+      "feeRange": [
+        1.6082474226804123,
+        1.6082474226804123,
+        1.6082474226804123,
+        1.6082474226804123,
+        1.2076788830715532,
+        3.166077738515901,
+        73.61111111111111
+      ]
+    },
+    {
+      "blockSize": 1809871,
+      "blockVSize": 997963,
+      "nTx": 4861,
+      "totalFees": 588436,
+      "medianFee": 1.6082474226804123,
+      "feeRange": [
+        1.5156626506024097,
+        1.5649475055559813,
+        1.5670103092783505,
+        1.6082474226804123,
+        1.6082474226804123,
+        1.6082474226804123,
+        1.6082474226804123
+      ]
+    },
+    {
+      "blockSize": 2917870,
+      "blockVSize": 997821.25,
+      "nTx": 1221,
+      "totalFees": 535389,
+      "medianFee": 1.5200034509958588,
+      "feeRange": [
+        1.35051546391752575,
+        1.5649475055559813,
+        1.5649475055559813,
+        1.5649475055559813,
+        1.5649475055559813,
+        1.5649475055559813,
+        1.5649475055559813
+      ]
+    },
+    {
+      "blockSize": 3937966,
+      "blockVSize": 997875.25,
+      "nTx": 18,
+      "totalFees": 506205,
+      "medianFee": 1.5100003123470801,
+      "feeRange": [
+        1.35051546391752575,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.5099980684971892,
+        1.5100003123470801,
+        1.5100020185186144,
+        1.5100025244589157
+      ]
+    },
+    {
+      "blockSize": 3917639,
+      "blockVSize": 997811.25,
+      "nTx": 62,
+      "totalFees": 503529,
+      "medianFee": 1.5099975959779666,
+      "feeRange": [
+        1.35051546391752575,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.5099971889756266,
+        1.5100002265056967
+      ]
+    },
+    {
+      "blockSize": 3694897,
+      "blockVSize": 997893.25,
+      "nTx": 43,
+      "totalFees": 503307,
+      "medianFee": 1.5099952023028946,
+      "feeRange": [
+        1.35051546391752575,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.3704911425797351,
+        1.5099952023028946,
+        1.5099967157103613
+      ]
+    },
+    {
+      "blockSize": 2486759,
+      "blockVSize": 997857.5,
+      "nTx": 498,
+      "totalFees": 386911,
+      "medianFee": 1.36001120750903104,
+      "feeRange": [
+        1.35051546391752575,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.5000054632270189
+      ]
+    },
+    {
+      "blockSize": 6681226,
+      "blockVSize": 3385616.5,
+      "nTx": 10222,
+      "totalFees": 1197838,
+      "medianFee": 1.35051546391752575,
+      "feeRange": [
+        1.21576460085542437,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.35051546391752575,
+        1.3599967979827291,
+        1.3600004002561639,
+        1.3600040026016911,
+        1.3600040026016911,
+        1.3600040026016911
+      ]
+    }
+  ]
+}
\ No newline at end of file