specification: API Commons Rate Limits
specificationVersion: '0.1'
provider: x402 List
providerId: x402-list-api
generated: '2026-09-02'
method: probed
source: >-
  Observed live on an unauthenticated GET https://x402-list.com/api/v1/stats
  (HTTP 200, 2026-09-02): the response carried x-ratelimit-limit: 200,
  x-ratelimit-remaining: 199, x-ratelimit-reset, x-meter-remaining: 1997 and
  x-meter-reset, and named all six headers in
  access-control-expose-headers. Documented at https://x402-list.com/api
  ("Rate Limiting") and in info.description of
  https://x402-list.com/api/v1/openapi.json.
description: >-
  Two independent throttles, both keyed on client IP and both signalled in
  response headers rather than only in prose: a 200 req/min sliding-window rate
  limit that returns 429 with Retry-After, and a 2,000 GET/day metering quota
  that returns 402 and can be paid through rather than waited out. The soft
  advisory band above 100 req/min is unusual and worth noting — requests still
  succeed, the API just tells the client it is approaching the ceiling.
scope: per-IP (no accounts or API keys exist)
limit_count: 2
headers:
  rateLimit: X-RateLimit-Limit
  rateLimitRemaining: X-RateLimit-Remaining
  rateLimitReset: X-RateLimit-Reset
  rateLimitThrottled: X-RateLimit-Throttled
  meterRemaining: X-Meter-Remaining
  meterReset: X-Meter-Reset
  retryAfter: Retry-After
  exposed_via: >-
    access-control-expose-headers: X-Meter-Remaining, X-Meter-Reset,
    X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset,
    X-RateLimit-Throttled
responseCodes:
  throttled: 429
  metered: 402
limits:
  - name: Request rate
    scope: ip
    metric: requests_per_minute
    limit: 200
    burst: null
    timeFrame: minute
    window: sliding, resets every minute
    on_exhaustion: >-
      429 Too Many Requests with a Retry-After header giving seconds until the
      window resets.
    advisory_threshold:
      above: 100
      behavior: >-
        X-RateLimit-Throttled: true is returned as an advisory signal; requests
        still succeed.
  - name: Free daily read quota (metering)
    scope: ip
    metric: get_requests_per_day
    limit: 2000
    timeFrame: day
    window: UTC day, resets at 00:00 UTC
    applies_to: GET /api/v1/*
    on_exhaustion: >-
      402 Payment Required carrying an x402 v2 PaymentRequired body (and the
      same object base64-encoded in the PAYMENT-REQUIRED header). Each further
      request costs $0.01 USDC on Base; retry with a PAYMENT-SIGNATURE header.
    observed:
      x_meter_remaining: 1997
      probed_at: '2026-09-02'
per_operation_limits:
  - operation: requestServiceUpdate
    limit: one update request per (email, service) pair every 7 days
    on_exhaustion: 429 with Retry-After
    note: Only a live or approved request holds the window; a rejected one does not.
  - operation: submitService
    limit: 7-day cooldown per submitter email, tracked separately per submission type
    note: >-
      A pending service submission does not block a facilitator submission from
      the same email. Submissions still pending after the 7-day review window are
      auto-rejected with an email notification.