Mempool

Mempool Fee Rates

Confirmed-history fee-rate estimates for target horizons.

Page Sections

GET

`/mempool/feerates`

Full URL: https://forcex.com/xtract/v1/litecoin/mempool/feerates

Credit cost: 1 credit.

curl -H "Authorization: Bearer fx_test_************" \
  "https://forcex.com/xtract/v1/litecoin/mempool/feerates?targets=1,3,6,24"

Parameters

Name	Location	Required	Type	Description
`targets`	query	no	string \| null	Comma-separated confirmation-target horizons (in blocks). Each entry must be an integer in `[1, 1008]`; at most 10 distinct horizons per request. Defaults to `1,3,6,24` when omitted. The response returns one fee-rate estimate per horizon, in input order, derived from the fee rates that confirmed in the last 144 blocks. This is a confirmed-history reference, NOT a live mempool snapshot — partners that need live mempool composition should use `GET /mempool` and `GET /mempool/{txid}`.

Request Body

No request body.

Example Response

Representative trimmed response. Use the OpenAPI schema for the exhaustive field contract.

{
  "data": [
    {
      "target_blocks": 1,
      "fee_rate_atomic_units_per_vbyte": 10
    },
    {
      "target_blocks": 6,
      "fee_rate_atomic_units_per_vbyte": 4
    }
  ],
  "meta": {
    "served_from": "indexed_store",
    "credit_cost": 1
  }
}

Documented Responses

Status	Description
`200`	Successful Response
`400`	Bad request. The `error.code` field identifies the specific cause: `bad_request` (general validation failure, including malformed dates, out-of-order ranges, and request-body validation), `range_too_large` (date range exceeds the per-grain cap), `ambiguous_time_range` (legacy `from`/`to` and new `start`/`end` supplied with differing values), or `invalid_include` (unsupported expansion in `?include=`).
`401`	Authentication required, or the supplied Bearer token is invalid or revoked. `error.code` = `auth_required`.
`402`	Payment-tier gate. `error.code` identifies which gate fired: `subscription_required` (no active subscription on the account), `subscription_inactive` (subscription exists but is not active), `include_all_requires_paid_tier` (sandbox keys cannot request `?include=all`), `include_set_requires_paid_tier` (the requested include set exceeds the per-request cost cap for sandbox keys), `historical_scan_requires_paid_tier` (sandbox keys cannot scan outside the recent window), or `deep_pagination_requires_paid_tier` (sandbox keys cannot page beyond the depth cap).
`403`	Authenticated but the key lacks the required scope. `error.code` = `scope_insufficient`.
`422`	Defense-in-depth: the runtime maps standard request-shape validation errors to 400, so partners normally see 400 instead of 422. This status is declared so any edge-case validation path that bypasses the override is still typed.
`429`	Rate limit or credit budget exceeded. `error.code` identifies the window: `rate_limit_exceeded` (per-second or per-minute), `quota_exceeded_daily` (sandbox per-day budget), or `quota_exceeded` (per-subscription-period). The body carries a `window` field (`second`, `minute`, `day`, or `month`) naming the failing limit. Responses include the standard `Retry-After` header.
`500`	Internal server error. `error.code` = `internal_error`. Reference `meta.request_id` when contacting support.
`503`	Service or downstream data store is temporarily unavailable, or the endpoint is not implemented in this API version. `error.code` identifies the cause: `data_unavailable` (chain tip not yet populated), `audit_unavailable` (request completed but audit could not be acknowledged — safe to retry), `plan_misconfigured` (operational issue on the API side; not a tier problem), or `endpoint_not_available` (the route is reserved and not yet served in this version).

Integration Notes

Targets are confirmation horizons in blocks.
The estimator is based on recently confirmed history, not live mempool composition.