# Mempool Space — Zapi reference

> Recommended fee tiers in sat/vB, as mempool.space's own estimator sees them.

**Base URL:** `https://api.zpi.web.id`
**Auth:** Send `x-api-key: YOUR_KEY` header on every request. Get a free key at https://zpi.web.id/dashboard/keys.
**Response envelope:** `{ content, message, errors }`
**Rate limit:** 60 req/min on free tier.

**Related:**
- Detail page: https://zpi.web.id/api/finance/mempool-space
- Endpoint catalog: https://zpi.web.id/category/finance
- Concise index: https://zpi.web.id/llms.txt
- Full reference: https://zpi.web.id/llms-full.txt

---

## Mempool Space

**Category:** finance · **Slug:** `mempool-space`
**Detail page:** https://zpi.web.id/api/finance/mempool-space

Recommended fee tiers in sat/vB, as mempool.space's own estimator sees them.

**Tags:** finance, mempool-space

### Fees

Recommended fee tiers in sat/vB, as mempool.space's own estimator sees them.

- **Method:** `GET`
- **Endpoint:** `https://api.zpi.web.id/v1/finance:mempool-space/fees`
- **Cache TTL:** 60s

**Parameters:**

_No parameters._

**cURL:**
```bash
curl "https://api.zpi.web.id/v1/finance:mempool-space/fees" \
  -H "x-api-key: YOUR_API_KEY"
```

**JavaScript / TypeScript:**
```javascript
const res = await fetch("https://api.zpi.web.id/v1/finance:mempool-space/fees", {
  headers: { "x-api-key": process.env.ZAPI_KEY }
});
const data = await res.json();
```

**Python:**
```python
import requests
r = requests.get("https://api.zpi.web.id/v1/finance:mempool-space/fees",
  headers={"x-api-key": "YOUR_API_KEY"})
data = r.json()
```

**Example response:**
```json
{
  "unit": "sat/vB",
  "dataset": "fees",
  "hourFee": 1,
  "provider": "mempool-space",
  "economyFee": 1,
  "fastestFee": 1,
  "minimumFee": 1,
  "halfHourFee": 1
}
```

---

### Blocks

The last 15 blocks, decorated with mempool.space's own per-block analysis.

- **Method:** `GET`
- **Endpoint:** `https://api.zpi.web.id/v1/finance:mempool-space/blocks`
- **Cache TTL:** 120s

**Parameters:**

| Name | Type | Location | Required | Description |
|------|------|----------|----------|-------------|
| `height` | number | query | no | Start height. Returns that block and the 14 below it. Omit for the chain tip. |

**cURL:**
```bash
curl "https://api.zpi.web.id/v1/finance:mempool-space/blocks?height=963330" \
  -H "x-api-key: YOUR_API_KEY"
```

**JavaScript / TypeScript:**
```javascript
const res = await fetch("https://api.zpi.web.id/v1/finance:mempool-space/blocks?height=963330", {
  headers: { "x-api-key": process.env.ZAPI_KEY }
});
const data = await res.json();
```

**Python:**
```python
import requests
r = requests.get("https://api.zpi.web.id/v1/finance:mempool-space/blocks?height=963330",
  headers={"x-api-key": "YOUR_API_KEY"})
data = r.json()
```

**Example response:**
```json
{
  "count": 15,
  "items": [
    {
      "bits": 386020669,
      "date": "2026-08-20T16:13:55.000Z",
      "hash": "000000000000000000012494c7465e63c75e19b5ea6fac791a9e17deb9b9821b",
      "size": 1692049,
      "time": 1787242435,
      "nonce": 4184907309,
      "stale": false,
      "avgFee": 494,
      "height": 963330,
      "poolId": 44,
      "reward": 314443642,
      "weight": 3994084,
      "txCount": 3932,
      "version": 637640704,
      "feeRange": [
        0,
        0,
        1,
        1,
        2,
        3,
        163
      ],
      "poolName": "AntPool",
      "poolSlug": "antpool",
      "avgTxSize": 430.19,
      "matchRate": 91.02,
      "medianFee": 1,
      "totalFees": 1943642,
      "avgFeeRate": 1,
      "difficulty": 127479855693691.4,
      "medianTime": 1787240341,
      "merkleRoot": "3a862f73950ada239a23900a5af2c1b096897c212c7c9c42af055837f65b1fce",
      "similarity": null,
      "totalInputs": 8803,
      "virtualSize": 998521,
      "expectedFees": 1983549,
      "totalOutputs": 8787,
      "utxoSetChange": -16,
      "expectedWeight": 3991925,
      "segwitTotalTxs": 3127,
      "totalOutputAmt": 916989493513,
      "coinbaseAddress": "37jKPSmbEGwgfacCr2nayn1wTaqMAbA94Z",
      "segwitTotalSize": 1554524,
      "previousBlockHash": "000000000000000000010b9a7c4cd90b904ae75d8a58b7583d24f8546bc3094d",
      "segwitTotalWeight": 3444092
    },
    {
      "bits": 386020669,
      "date": "2026-08-20T16:10:10.000Z",
      "hash": "000000000000000000010b9a7c4cd90b904ae75d8a58b7583d24f8546bc3094d",
      "size": 1687761,
      "time": 1787242210,
      "nonce": 497520903,
      "stale": false,
      "avgFee": 960,
      "height": 963329,
      "poolId": 115,
      "reward": 315138459,
      "weight": 3994731,
      "txCount": 2747,
      "version": 537919488,
      "feeRange": [
        0,
        0,
        1,
        2,
        2,
        4,
        74
      ],
      "poolName": "MARA Pool",
      "poolSlug": "marapool",
      "avgTxSize": 614.29,
      "matchRate": 97.92,
      "medianFee": 2,
      "totalFees": 2638459,
      "avgFeeRate": 2,
      "difficulty": 127479855693691.4,
      "medianTime": 1787240064,
      "merkleRoot": "3b8f723ecb4bc3f5f47e8bab0964479c726633d78bf0db82bf9583ffa1cf197b",
      "similarity": null,
      "totalInputs": 9417,
      "virtualSize": 998682.75,
      "expectedFees": 2860693,
      "totalOutputs": 6595,
      "utxoSetChange": -2822,
      "expectedWeight": 3991950,
      "segwitTotalTxs": 2474,
      "totalOutputAmt": 880748033230,
      "coinbaseAddress": "32i1m6gNcSHwiPX9nfTNXVjme9j5DU8y5g",
      "segwitTotalSize": 1521952,
      "previousBlockHash": "000000000000000000007f37c59f2281d657b83257db8788a26572c5e7369b29",
      "segwitTotalWeight": 3331603
    },
    {
      "bits": 386020669,
      "date": "2026-08-20T16:05:37.000Z",
      "hash": "000000000000000000007f37c59f2281d657b83257db8788a26572c5e7369b29",
      "size": 1548015,
      "time": 1787241937,
      "nonce": 3099071765,
      "stale": false,
      "avgFee": 906,
      "height": 963328,
      "poolId": 73,
      "reward": 315854966,
      "weight": 3993615,
      "txCount": 3703,
      "version": 699105280,
      "feeRange": [
        0,
        1,
        2,
        3,
        3,
        5,
        105
      ],
      "poolName": "ViaBTC",
      "poolSlug": "viabtc",
      "avgTxSize": 417.92,
      "matchRate": 97.2,
      "medianFee": 3,
      "totalFees": 3354966,
      "avgFeeRate": 3,
      "difficulty": 127479855693691.4,
      "medianTime": 1787239225,
      "merkleRoot": "36fbc55f29dad244a6578994f499d3ce0b39b7990fdcfb5bc61b3056468c243c",
      "similarity": null,
      "totalInputs": 7719,
      "virtualSize": 998403.75,
      "expectedFees": 3406355,
      "totalOutputs": 8437,
      "utxoSetChange": 718,
      "expectedWeight": 3991908,
      "segwitTotalTxs": 3301,
      "totalOutputAmt": 1463544994069,
      "coinbaseAddress": "1PuJjnF476W3zXfVYmJfGnouzFDAXakkL4",
      "segwitTotalSize": 1358046,
      "previousBlockHash": "00000000000000000001ae083ea48f0a77511d01b73c4b27e8e7b77bd4363223",
      "segwitTotalWeight": 3233847
    },
    {
      "bits": 386020669,
      "date": "2026-08-20T15:59:03.000Z",
      "hash": "00000000000000000001ae083ea48f0a77511d01b73c4b27e8e7b77bd4363223",
      "size": 1576510,
      "time": 1787241543,
      "nonce": 3391365394,
      "stale": false,
      "avgFee": 1085,
      "height": 963327,
      "poolId": 111,
      "reward": 317434742,
      "weight": 3993112,
      "txCount": 4547,
      "version": 537460736,
      "feeRange": [
        0,
        2,
        3,
        4,
        5,
        6,
        301
      ],
      "poolName": "Foundry USA",
      "poolSlug": "foundryusa",
      "avgTxSize": 346.65000000000003,
      "matchRate": 98.92,
      "medianFee": 4,
      "totalFees": 4934742,
      "avgFeeRate": 4,
      "difficulty": 127479855693691.4,
      "medianTime": 1787239084,
      "merkleRoot": "bead81fc0127a59fda9b9366f2a9c22c5502d368f8f72a3166ab73dc7e8bb38f",
      "similarity": null,
      "totalInputs": 7362,
      "virtualSize": 998278,
      "expectedFees": 4980508,
      "totalOutputs": 11810,
      "utxoSetChange": 4448,
      "expectedWeight": 3991883,
      "segwitTotalTxs": 4285,
      "totalOutputAmt": 1263242911274,
      "coinbaseAddress": "bc1qwzrryqr3ja8w7hnja2spmkgfdcgvqwp5swz4af4ngsjecfz0w0pqud7k38",
      "segwitTotalSize": 1494062,
      "previousBlockHash": "00000000000000000000cb181d3340ebcc9bb3def8fd21e71a8fc5e6e500c2b6",
      "segwitTotalWeight": 3663428
    },
    {
      "bits": 386020669,
      "date": "2026-08-20T15:39:27.000Z",
      "hash": "00000000000000000000cb181d3340ebcc9bb3def8fd21e71a8fc5e6e500c2b6",
      "size": 1715125,
      "time": 1787240367,
      "nonce": 2187032938,
      "stale": false,
      "avgFee": 372,
      "height": 963326,
      "poolId": 73,
      "reward": 313786694,
      "weight": 3993529,
      "txCount": 3457,
      "version": 536944640,
      "feeRange": [
        0,
        0,
        1,
        1,
        1,
        1,
        60
      ],
      "poolName": "ViaBTC",
      "poolSlug": "viabtc",
      "avgTxSize": 496,
      "matchRate": 94.59,
      "medianFee": 1,
      "totalFees": 1286694,
      "avgFeeRate": 1,
      "difficulty": 127479855693691.4,
      "medianTime": 1787238880,
      "merkleRoot": "35142a559442b7c4a1bb0d8b55edebe3cfa506ba36997421a03983d2c12bebfe",
      "similarity": null,
      "totalInputs": 8966,
      "virtualSize": 998382.25,
      "expectedFees": 1303252,
      "totalOutputs": 6963,
      "utxoSetChange": -2003,
      "expectedWeight": 3991896,
      "segwitTotalTxs": 3196,
      "totalOutputAmt": 671518441880,
      "coinbaseAddress": "1PuJjnF476W3zXfVYmJfGnouzFDAXakkL4",
      "segwitTotalSize": 1570440,
      "previousBlockHash": "00000000000000000001cf93d5567acdbcf00d32bc9e160dffc625949774b9b2",
      "segwitTotalWeight": 3414897
    },
    {
      "bits": 386020669,
      "date": "2026-08-20T15:39:01.000Z",
      "hash": "00000000000000000001cf93d5567acdbcf00d32bc9e160dffc625949774b9b2",
      "size": 1600039,
      "time": 1787240341,
      "nonce": 1935619878,
      "stale": false,
      "avgFee": 897,
      "height": 963325,
      "poolId": 102,
      "reward": 315722504,
      "weight": 3993655,
      "txCount": 3592,
      "version": 536936448,
      "feeRange": [
        0,
        1,
        2,
        2,
        3,
        5,
        200
      ],
      "poolName": "SpiderPool",
      "poolSlug": "spiderpool",
      "avgTxSize": 445.3,
      "matchRate": 99.03,
      "medianFee": 2,
      "totalFees": 3222504,
      "avgFeeRate": 3,
      "difficulty": 127479855693691.4,
      "medianTime": 1787238429,
      "merkleRoot": "c539da26f745fd83c905ef7220a51812f8f89abd9977f4886fa2df3c79290255",
      "similarity": null,
      "totalInputs": 8655,
      "virtualSize": 998413.75,
      "expectedFees": 3223292,
      "totalOutputs": 7943,
      "utxoSetChange": -712,
      "expectedWeight": 3991764,
      "segwitTotalTxs": 3174,
      "totalOutputAmt": 921523360758,
      "coinbaseAddress": "1BM1sAcrfV6d4zPKytzziu4McLQDsFC2Qc",
      "segwitTotalSize": 1390155,
      "previousBlockHash": "000000000000000000022f062782ab666902fda1b880ec7ce12b76193b622ccc",
      "segwitTotalWeight": 3154227
    },
    {
      "bits": 386020669,
      "date": "2026-08-20T15:34:24.000Z",
      "hash": "000000000000000000022f062782ab666902fda1b880ec7ce12b76193b622ccc",
      "size": 1598037,
      "time": 1787240064,
      "nonce": 2501336116,
      "stale": false,
      "avgFee": 1105,
      "height": 963324,
      "poolId": 44,
      "reward": 317507570,
      "weight": 3994074,
      "txCount": 4532,
      "version": 544079872,
      "feeRange": [
        0,
        2,
        3,
        4,
        5,
        6,
        302
      ],
      "poolName": "AntPool",
      "poolSlug": "antpool",
      "avgTxSize": 352.49,
      "matchRate": 98.35,
      "medianFee": 4,
      "totalFees": 5007570,
      "avgFeeRate": 5,
      "difficulty": 127479855693691.4,
      "medianTime": 1787235905,
      "merkleRoot": "bd851bfe999ca91f8e9064a7600ca82ce686aa658d261505a3bbabc37d8cf0de",
      "similarity": null,
      "totalInputs": 7660,
      "virtualSize": 998518.5,
      "expectedFees": 5102042,
      "totalOutputs": 11360,
      "utxoSetChange": 3700,
      "expectedWeight": 3991893,
      "segwitTotalTxs": 4211,
      "totalOutputAmt": 1566054329974,
      "coinbaseAddress": "37jKPSmbEGwgfacCr2nayn1wTaqMAbA94Z",
      "segwitTotalSize": 1515137,
      "previousBlockHash": "00000000000000000001bb8da6308e5994a943ca1dfb30bfbc7575a487d736c0",
      "segwitTotalWeight": 3662582
    },
    {
      "bits": 386020669,
      "date": "2026-08-20T15:20:25.000Z",
      "hash": "00000000000000000001bb8da6308e5994a943ca1dfb30bfbc7575a487d736c0",
      "size": 1548415,
      "time": 1787239225,
      "nonce": 3459762381,
      "stale": false,
      "avgFee": 894,
      "height": 963323,
      "poolId": 44,
      "reward": 314996382,
      "weight": 3993928,
      "txCount": 2793,
      "version": 638132224,
      "feeRange": [
        0,
        2,
        2,
        2,
        2,
        3,
        106
      ],
      "poolName": "AntPool",
      "poolSlug": "antpool",
      "avgTxSize": 554.19,
      "matchRate": 93.59,
      "medianFee": 2,
      "totalFees": 2496382,
      "avgFeeRate": 2,
      "difficulty": 127479855693691.4,
      "medianTime": 1787235519,
      "merkleRoot": "e92af7ac9ccddfe04261334686fd3eb35fd25b653cd5b28c8dd3df3c2a08bf66",
      "similarity": null,
      "totalInputs": 8457,
      "virtualSize": 998482,
      "expectedFees": 2617355,
      "totalOutputs": 6300,
      "utxoSetChange": -2157,
      "expectedWeight": 3991687,
      "segwitTotalTxs": 2548,
      "totalOutputAmt": 754662897109,
      "coinbaseAddress": "37jKPSmbEGwgfacCr2nayn1wTaqMAbA94Z",
      "segwitTotalSize": 1240188,
      "previousBlockHash": "00000000000000000001b526d9c88a240b124f0b2e406b413627ac76cbe4973a",
      "segwitTotalWeight": 2761128
    }
  ],
  "height": 963330,
  "dataset": "blocks",
  "provider": "mempool-space"
}
```

---

### Mempool

Pending transactions and the fee-rate histogram behind them.

- **Method:** `GET`
- **Endpoint:** `https://api.zpi.web.id/v1/finance:mempool-space/mempool`
- **Cache TTL:** 60s

**Parameters:**

_No parameters._

**cURL:**
```bash
curl "https://api.zpi.web.id/v1/finance:mempool-space/mempool" \
  -H "x-api-key: YOUR_API_KEY"
```

**JavaScript / TypeScript:**
```javascript
const res = await fetch("https://api.zpi.web.id/v1/finance:mempool-space/mempool", {
  headers: { "x-api-key": process.env.ZAPI_KEY }
});
const data = await res.json();
```

**Python:**
```python
import requests
r = requests.get("https://api.zpi.web.id/v1/finance:mempool-space/mempool",
  headers={"x-api-key": "YOUR_API_KEY"})
data = r.json()
```

**Example response:**
```json
{
  "count": 226,
  "items": [
    {
      "vsize": 93728,
      "feeRate": 5.0099845
    },
    {
      "vsize": 51246,
      "feeRate": 2.8633094
    },
    {
      "vsize": 54421,
      "feeRate": 2
    },
    {
      "vsize": 62099,
      "feeRate": 1.005336
    },
    {
      "vsize": 50137,
      "feeRate": 0.70642203
    },
    {
      "vsize": 50840,
      "feeRate": 0.5343321
    },
    {
      "vsize": 52056,
      "feeRate": 0.5043951
    },
    {
      "vsize": 52014,
      "feeRate": 0.500987
    }
  ],
  "vsize": 43778589,
  "dataset": "mempool",
  "txCount": 84482,
  "provider": "mempool-space",
  "totalFee": 8637374
}
```

---

### Difficulty Adjustment

Retarget progress and the difficulty change mempool.space projects from it.

- **Method:** `GET`
- **Endpoint:** `https://api.zpi.web.id/v1/finance:mempool-space/difficulty-adjustment`
- **Cache TTL:** 120s

**Parameters:**

_No parameters._

**cURL:**
```bash
curl "https://api.zpi.web.id/v1/finance:mempool-space/difficulty-adjustment" \
  -H "x-api-key: YOUR_API_KEY"
```

**JavaScript / TypeScript:**
```javascript
const res = await fetch("https://api.zpi.web.id/v1/finance:mempool-space/difficulty-adjustment", {
  headers: { "x-api-key": process.env.ZAPI_KEY }
});
const data = await res.json();
```

**Python:**
```python
import requests
r = requests.get("https://api.zpi.web.id/v1/finance:mempool-space/difficulty-adjustment",
  headers={"x-api-key": "YOUR_API_KEY"})
data = r.json()
```

**Example response:**
```json
{
  "dataset": "difficulty-adjustment",
  "provider": "mempool-space",
  "timeOffset": 0,
  "previousDate": "2026-08-08T19:35:55.000Z",
  "previousTime": 1786217755,
  "expectedBlocks": 1768.8733333333332,
  "timeAvgSeconds": 609,
  "progressPercent": 86.5079365079365,
  "remainingBlocks": 272,
  "difficultyChange": -1.3496349842272548,
  "previousRetarget": 0.9889358055576736,
  "remainingSeconds": 165528,
  "nextRetargetHeight": 963648,
  "estimatedRetargetDate": "2026-08-23T00:23:26.504Z",
  "estimatedRetargetTime": 1787444607,
  "adjustedTimeAvgSeconds": 609
}
```

---

### Fee Projection

The blocks mempool.space projects from the current mempool, by fee band.

- **Method:** `GET`
- **Endpoint:** `https://api.zpi.web.id/v1/finance:mempool-space/fee-projection`
- **Cache TTL:** 60s

**Parameters:**

_No parameters._

**cURL:**
```bash
curl "https://api.zpi.web.id/v1/finance:mempool-space/fee-projection" \
  -H "x-api-key: YOUR_API_KEY"
```

**JavaScript / TypeScript:**
```javascript
const res = await fetch("https://api.zpi.web.id/v1/finance:mempool-space/fee-projection", {
  headers: { "x-api-key": process.env.ZAPI_KEY }
});
const data = await res.json();
```

**Python:**
```python
import requests
r = requests.get("https://api.zpi.web.id/v1/finance:mempool-space/fee-projection",
  headers={"x-api-key": "YOUR_API_KEY"})
data = r.json()
```

**Example response:**
```json
{
  "unit": "sat/vB",
  "count": 8,
  "items": [
    {
      "txCount": 5458,
      "feeRange": [
        0.5004868549172347,
        0.5029596412556053,
        0.5058749663646964,
        0.5320310255673657,
        0.5946145333825157,
        1.019225839528326,
        30.54054054054054
      ],
      "blockSize": 1605900,
      "medianFee": 0.5322800718132853,
      "totalFees": 1153306,
      "blockIndex": 0,
      "blockVsize": 997950
    },
    {
      "txCount": 3215,
      "feeRange": [
        0.41651705565529623,
        0.41759319816873774,
        0.41759319816873774,
        0.43198191835004945,
        0.452189949285385,
        0.4853376378800108,
        0.5008757456530016
      ],
      "blockSize": 2082583,
      "medianFee": 0.4320060088865006,
      "totalFees": 444893,
      "blockIndex": 1,
      "blockVsize": 997999
    },
    {
      "txCount": 7165,
      "feeRange": [
        0.3838383838383838,
        0.41651705565529623,
        0.41651705565529623,
        0.41651705565529623,
        0.41651705565529623,
        0.41656104773975494,
        0.41756594724220625
      ],
      "blockSize": 1583481,
      "medianFee": 0.4165170556552962,
      "totalFees": 415722,
      "blockIndex": 2,
      "blockVsize": 997993.5
    },
    {
      "txCount": 6938,
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      "totalFees": 403880,
      "blockIndex": 3,
      "blockVsize": 997987
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      "feeRange": [
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      "blockVsize": 997973.5
    },
    {
      "txCount": 60,
      "feeRange": [
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      "medianFee": 0.37402867234573034,
      "totalFees": 372841,
      "blockIndex": 5,
      "blockVsize": 997991.75
    },
    {
      "txCount": 252,
      "feeRange": [
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      "blockSize": 2999333,
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      "totalFees": 313519,
      "blockIndex": 6,
      "blockVsize": 997893.5
    },
    {
      "txCount": 60988,
      "feeRange": [
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      "blockSize": 112784000,
      "medianFee": 0.13023565659089015,
      "totalFees": 5163610,
      "blockIndex": 7,
      "blockVsize": 36822692.75
    }
  ],
  "dataset": "fee-projection",
  "provider": "mempool-space"
}
```

---


_Generated: 2026-08-21T07:37:47.636Z_