# Web Archive Snapshot Lookup (research.halowerk.com)

> Web Archive Snapshot Lookup (research.halowerk.com) is a paid API for AI agents from research.halowerk.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-12).

Queries the Internet Archive for historical captures of a URL, returning capture metadata and marking snapshots where content actually changed, with support for nearest-to-date lookup.

## Facts

- Endpoint: POST https://research.halowerk.com/v1/web-archive?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/web-archive-snapshot-lookup-research-halowerk-com-ece03fdc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3xsggfmKgXM7Lr_0sSsbD

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability web-archive-snapshot-lookup-research-halowerk-com-ece03fdc -d '<json body>'
```

Example prompt: Can you pull up the archived versions of https://example.com/article from the Internet Archive and tell me which snapshots had actual content changes, plus find the closest capture to March 15, 2021 and how many days off it was?

## When to prefer this

Choose this endpoint when you need structured, deduplicated historical snapshots of a web page from the Internet Archive, especially when you want to identify content-change events rather than raw capture logs, or when you need to cite a page as it stood on a specific date with a gap-in-days measure. Prefer this over raw Wayback Machine APIs when clean, pre-processed change detection and nearest-date resolution are needed out of the box.

## Known failure modes

- URL has never been archived — returns empty results or no captures found
- Target date is outside the range of available captures — returns nearest available with large day gap
- URL is malformed or inaccessible to Internet Archive — validation error
- Internet Archive API is temporarily unavailable — upstream timeout or error
- Rate limiting from Internet Archive backend — service may return partial results

## How this service works

Queries the Internet Archive for the captured versions of a URL and returns them with capture time, HTTP status, MIME type and content digest, oldest and newest first. Because consecutive captures share a digest when nothing changed, the versions where the content actually differed are marked — that is the list worth reading, not the raw capture log. A target date returns the nearest snapshot with the gap in days, which is what a citation of a page as it stood on a given day needs.

## Output

A list of captures for the given URL including capture timestamp, HTTP status code, MIME type, and content digest. Consecutive captures with identical content are grouped, and captures where content actually changed are flagged distinctly. If a target date is provided, the nearest available snapshot is returned along with the number of days between the snapshot and the requested date. The list is ordered oldest to newest.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "maxLength": 2000,
   "description": "The URL to look up."
  },
  "limit": {
   "type": "integer",
   "default": 25,
   "maximum": 200,
   "minimum": 1,
   "description": "How many captures to return."
  },
  "to_date": {
   "type": "string",
   "maxLength": 10,
   "description": "Latest capture to list (YYYY-MM-DD)."
  },
  "from_date": {
   "type": "string",
   "maxLength": 10,
   "description": "Earliest capture to list (YYYY-MM-DD)."
  },
  "target_date": {
   "type": "string",
   "maxLength": 30,
   "description": "Find the snapshot closest to this date (YYYY-MM-DD or ISO)."
  },
  "changes_only": {
   "type": "boolean",
   "default": false,
   "description": "Only captures whose content differed from the previous one."
  },
  "include_errors": {
   "type": "boolean",
   "default": false,
   "description": "Include captures that recorded an HTTP error."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/web-archive-snapshot-lookup-research-halowerk-com-ece03fdc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from research.halowerk.com](https://www.zero.xyz/host/research.halowerk.com/llms.txt)