# H1 Text Length Ranking

> H1 Text Length Ranking is a paid API for AI agents from market.datapackvibe.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-13).

Ranks level-one heading (H1) text length relative to a reference term and previous texts for a given webpage or HTML snippet

## Facts

- Endpoint: POST https://market.datapackvibe.com/x402/assistant-bx-web-h1-rank?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/h1-text-length-ranking-1bb5f6c2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rqyxCUbzRG847VZBhAUt_

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 h1-text-length-ranking-1bb5f6c2 -d '<json body>'
```

Example prompt: Can you rank the text length of the H1 headings on https://example.com/product-guide against the term 'product', comparing it to these previous headings: ['Old product guide', 'Beginner product overview']?

## When to prefer this

Choose this endpoint when you need a quick, static, cost-efficient ranking of H1 heading text length on a public webpage or a supplied HTML snippet, especially when comparing against historical headings or a specific keyword term. It is ideal for SEO audits, content length benchmarking, and heading optimization workflows where JavaScript rendering is not required.

## Known failure modes

- URL is unreachable or returns a non-200 status — parsing fails with an error
- No H1 element found on the page or in the HTML — returns empty or null ranking
- HTML content exceeds 100,000 character limit — request rejected
- Term parameter missing or empty — validation error
- JavaScript-rendered content not available since only static parsing is performed
- URL requires authentication or login — content inaccessible

## How this service works

Level-one headings — Text length ranking: Text length ranking for Level-one headings. One public HTTPS page or supplied HTML; static parsing, no JavaScript rendering, login or access bypass. Specialised preset in a shared 50-profile, 20-operation engine. 0.01 USDC includes one bounded text length ranking result.

## Output

Returns a bounded text length ranking result for the H1 heading found on the specified page or in the supplied HTML, scored relative to the provided term and any previously supplied heading texts. Includes the ranking value and contextual comparison data.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "default": "",
   "maxLength": 2048
  },
  "html": {
   "type": "string",
   "default": "<!doctype html><html><head></head><body><h1 id=\"sample\" data-kind=\"example\">Example product guide</h1></body></html>",
   "maxLength": 100000
  },
  "term": {
   "type": "string",
   "default": "product",
   "maxLength": 100,
   "minLength": 1
  },
  "attribute": {
   "type": "string",
   "default": "id",
   "pattern": "^[a-zA-Z][a-zA-Z0-9:_-]{0,49}$",
   "maxLength": 50
  },
  "previous_texts": {
   "type": "array",
   "items": {
    "type": "string",
    "default": "",
    "maxLength": 1000
   },
   "default": [
    "Older example"
   ],
   "maxItems": 200,
   "minItems": 0
  },
  "attribute_value": {
   "type": "string",
   "default": "sample",
   "maxLength": 200
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/h1-text-length-ranking-1bb5f6c2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from market.datapackvibe.com](https://www.zero.xyz/host/market.datapackvibe.com/llms.txt)