How to hit the mempool.space API

mempool.space at https://mempool.space/api is an open-source Bitcoin explorer: fee estimates, mempool state, blocks, and address history.

Authentication

None — no key, no signup. Every example runs as-is.

Full reference: https://mempool.space/docs/api/rest

Recommended fees

In sat/vB, by how fast you want confirmation.

curl https://mempool.space/api/v1/fees/recommended
Run in PostTaco
Example response (trimmed) 
{
  "fastestFee": 3,
  "halfHourFee": 1,
  "hourFee": 1,
  "economyFee": 1,
  "minimumFee": 1
}

Mempool summary

curl https://mempool.space/api/mempool
Run in PostTaco
Example response (trimmed) 
{
  "count": 83272,
  "vsize": 42016410,
  "total_fee": 10505804,
  "fee_histogram": [
    [
      6.5510206,
      50030
    ],
    [
      4.225989,
      50137
    ]
  ]
}

Latest blocks

curl https://mempool.space/api/v1/blocks
Run in PostTaco
Example response (trimmed) 
[
  {
    "id": "000000000000000000012527259d4144114128f6d0928dfc6bf71955782c0790",
    "height": 968323,
    "version": 564174848,
    "timestamp": 1790199102,
    "bits": 386014917,
    "nonce": 3996924990,
    "difficulty": 132757073449487.5,
    "merkle_root": "ee60f12fbef8cddca648c5606864c6821c57f531658afbfa1f678c66955638e2",
    "tx_count": 3088,
    "size": 1920382,
    "weight": 3993070,
    "previousblockhash": "000000000000000000003fdcc5dd430bb71bdfa74152d914296217f8ddfaf9a2",
    "mediantime": 1790196294,
    "stale": false,
    "extras": {
      "reward": 314789328,
      "coinbaseRaw": "0383c60e04fcd83e452f466f756e6472792055534120506f6f6c202364726f70676f6c642f91955b84ee06000000000000",
      "orphans": [],
      "medianFee": 1.0002421633257097,
      "feeRange": [
        0.5818181818181818,
        0.6801665404996216
      ],
      "totalFees": 2289328,
      "avgFee": 741,
      "avgFeeRate": 2,
      "utxoSetChange": -345,
      "avgTxSize": 621.79,
      "totalInputs": 7259,
      "totalOutputs": 6914,
      "totalOutputAmt": 645884682778,
      "segwitTotalTxs": 2791,
      "segwitTotalSize": 1727106
    }
  },
  {
    "id": "000000000000000000003fdcc5dd430bb71bdfa74152d914296217f8ddfaf9a2",
    "height": 968322,
    "version": 893452288,
    "timestamp": 1790198781,
    "bits": 386014917,
    "nonce": 21103080,
    "difficulty": 132757073449487.5,
    "merkle_root": "f125a616f45f57f30d43af1a7234b90c87d966ba565ce7d33c2e8db6f49f0372",
    "tx_count": 4687,
    "size": 1595526,
    "weight": 3997803,
    "previousblockhash": "00000000000000000000da5d4d53b58a4b52a2a8fc7eb2a7abde59f691ebc7a5",
    "mediantime": 1790195331,
    "stale": false,
    "extras": {
      "reward": 314769873,
      "coinbaseRaw": "0382c60e2cfabe6d6d5f585a50fefc7654eb8f828b46e482d6f112ff7ad2612cc48140fc90358e6eee10000000f09f909f092f4632506f6f6c2f6400000000000000000000000000000000000000000000000000000000000000000000000500354fb6d4",
      "orphans": [],
      "medianFee": 2.0012488357458813,
      "feeRange": [
        1.0028169014084507,
        1.0044444444444445
      ],
      "totalFees": 2269873,
      "avgFee": 484,
      "avgFeeRate": 2,
      "utxoSetChange": 2640,
      "avgTxSize": 340.28000000000003,
      "totalInputs": 8015,
      "totalOutputs": 10655,
      "totalOutputAmt": 870477675310,
      "segwitTotalTxs": 4247,
      "segwitTotalSize": 1460000
    }
  }
]