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Reverse Agent API – URL Freshness Checker
x402
Reverse Agent API – URL Freshness Checker is a paid API for AI agents from reversecaptcha.fun, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-23).
Checks whether a given HTTPS URL's content is fresh (recently updated) within a specified maximum age, returning a freshness verdict, confidence level, and age estimate based on HTTP signals.
Price / call$0.01
Success—
StatusUnknown
How this service works
Reverse Agent API by reverse.captcha — pay-per-use security and web utilities for autonomous agents.
Output
Returns a JSON object with: ok (boolean success flag), freshness ('fresh' or 'stale'), confidence ('high'/'medium'/'low'), age_seconds (estimated age of the content), evidence_source (e.g. 'http:last-modified' indicating which HTTP signal was used), is_within_max_age (boolean), and evidence_timestamp (ISO 8601 timestamp of the detected last modification).
Example use cases
News article freshness gate
“Before I summarize this article, check if https://reuters.com/technology/ai-news is fresh — I only want to proceed if it was updated within the last 2 hours (7200 seconds).”
Monitoring a competitor's pricing page
“Check whether https://competitor.com/pricing has been updated in the past week (604800 seconds) — I need to know if their prices have likely changed recently.”
Validating a data feed before ingestion
“Before I ingest the data from https://data.provider.com/feed/latest.json, verify it's fresh and was updated within the last 10 minutes (600 seconds) so I'm not working with stale data.”
Technical details
Endpoint
POSThttps://reversecaptcha.fun/v1/paid/freshness?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a quick, pay-per-use signal about whether a specific HTTPS URL's content is recent, especially in agentic pipelines that gate downstream actions on content freshness. Ideal when you don't want to build your own HTTP header parsing logic and need a structured confidence-scored verdict. Prefer it over manual HTTP HEAD requests when you need normalized output including estimated age and evidence sourcing.
Side effects
- URL is not HTTPS — rejected by schema pattern validation
- URL is unreachable or returns non-200 status — may return ok:false or low confidence
- No HTTP freshness signals available (no Last-Modified, no ETag, no cache headers) — returns low confidence result
- max_age_seconds below minimum of 60 or above maximum of 2678400 — request rejected
- Payment failure via x402 protocol — call not executed
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string | |
| max_age_seconds | integer |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"freshness": "fresh",
"confidence": "medium",
"age_seconds": 320,
"evidence_source": "http:last-modified",
"is_within_max_age": true,
"evidence_timestamp": "2026-01-01T00:00:00.000Z"
}
}Tags
x402
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