BTCintel
nodeok
tip971,672
mempool68,600 tx
node next1.08 sat/vB
retarget40 blocks
chainmainnet

Docs

Mempool and fees

The node's mempool as btcintel mirrors it, the projected next blocks, replacements and fee estimates — projection and node figures kept apart.

Generated from openapi.yaml (Btcintel native API 0.1.0). Every hash is canonical display order; every answer carries the index and node heights; errors use one envelope — see Semantics.

GET /v1/mempool

Recent mempool transactions

Newest 500 entries with fee, vsize and first sighting; totals live in /v1/mempool/stats.

Response 200

Mempool sample.

schema
array of MempoolTx
  • txid string — Canonical display byte order.
  • fee_sat integer
  • vsize integer
  • fee_rate number — sat/vB, 2 decimals.
  • first_seen string (date-time)

Example

curl -s https://api.btcintel.io/v1/mempool | jq

GET /v1/mempool/txids

Txids of the mempool sample

Response 200

Canonical txids.

schema
array of string

Example

curl -s https://api.btcintel.io/v1/mempool/txids | jq

GET /v1/mempool/stats

Whole-mempool statistics

Response 200

Count, vsize, total fee and fee-rate histogram over the full mirrored mempool.

schema
  • count integer
  • vsize integer
  • total_fee integer
  • fee_histogram array of array of number — [fee_rate_bucket_floor_satvb, vsize] pairs, high to low.

Example

curl -s https://api.btcintel.io/v1/mempool/stats | jq '{count, vsize, total_fee}'

GET /v1/mempool/projected

Projected blocks (mempool engine, ADR-0003)

The mempool packed into template-sized blocks by effective (ancestor package) fee rate — the getblocktemplate approach. Up to 8 blocks described individually; the rest aggregated under remaining.

Response 200

Projection snapshot (recomputed every ~2 s).

schema
  • blocks array of ProjectedBlock
    • ntx integer
    • vsize integer
    • weight integer
    • total_fee_sat integer
    • fee_range array of number — [lowest, highest] effective sat/vB in this slice.
    • median_rate number — vsize-weighted median of package rates; absent on remaining.
  • remaining one of — Aggregate past the detailed horizon; fee_range uses base rates there.
    • ProjectedBlock
      • ntx integer
      • vsize integer
      • weight integer
      • total_fee_sat integer
      • fee_range array of number — [lowest, highest] effective sat/vB in this slice.
      • median_rate number — vsize-weighted median of package rates; absent on remaining.
    • null
  • remaining_blocks integer — ceil(remaining weight / block budget).
  • tx_count integer
  • as_of string (date-time)

Errors

  • 501 — The mempool engine is not enabled on this deployment (BITCOIN_ZMQ_SEQUENCE unset).
  • 503 — Engine bootstrapping; retry shortly.

Example

curl -s https://api.btcintel.io/v1/mempool/projected | jq '{remaining_blocks, tx_count, as_of}'

GET /v1/mempool/replacements

Recent RBF replacements (mempool engine, ADR-0003)

Replacements observed by outpoint conflict — independent of BIP125 signaling, so full-RBF replacements are included. Newest first.

Parameters

NameInTypeDescription
limitqueryinteger · ≤ 200 · default 25—

Response 200

Replacement events.

schema
array of Replacement
  • txid string — Canonical display byte order.
  • fee_sat integer
  • vsize integer
  • rate number — sat/vB.
  • replaced array of object
    • txid string — Canonical display byte order.
    • fee_sat integer
    • vsize integer
    • rate number
  • at string (date-time)

Errors

  • 501 — The mempool engine is not enabled on this deployment (BITCOIN_ZMQ_SEQUENCE unset).
  • 503 — Engine bootstrapping; retry shortly.

Example

curl -s https://api.btcintel.io/v1/mempool/replacements | jq

GET /v1/fees/estimates

Fee recommendations (mempool engine, ADR-0003)

Derived from the projection's vsize-weighted medians, floored at the node's mempool minimum and monotonic (fastest ≥ half_hour ≥ hour ≥ economy ≥ minimum). The node's estimatesmartfee (targets 1/3/6) rides along under node for comparison — never blended in.

Response 200

Recommendations in sat/vB.

schema
  • fastest number — Median of projected block 1, sat/vB.
  • half_hour number — Median of projected block 3.
  • hour number — Median of projected block 6.
  • economy number — Median of the last detailed block.
  • minimum number — Node mempool floor (mempoolminfee).
  • node object — estimatesmartfee sat/vB by target ("1", "3", "6"), for comparison.
  • basis object
    • tx_count integer
    • vsize integer
  • as_of string (date-time)

Errors

  • 501 — The mempool engine is not enabled on this deployment (BITCOIN_ZMQ_SEQUENCE unset).
  • 503 — Engine bootstrapping; retry shortly.

Example

curl -s https://api.btcintel.io/v1/fees/estimates | jq '{fastest, half_hour, hour}'