# Footer Blocks — Invisible Character Flags

> Footer Blocks — Invisible Character Flags is a paid API for AI agents from market.datapackvibe.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-16).

Detects and flags invisible/hidden Unicode characters present in the footer blocks of a webpage or supplied HTML snippet.

## Facts

- Endpoint: POST https://market.datapackvibe.com/x402/assistant-bx-web-footers-unicode?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/footer-blocks-invisible-character-flags-1b9bb191
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cGiEa5wp_v8b4QbOx63nf

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 footer-blocks-invisible-character-flags-1b9bb191 -d '<json body>'
```

Example prompt: Check the footer of https://example.com for any invisible or hidden Unicode characters — specifically look at the element with id 'footer-main' and flag anything suspicious related to the term 'privacy'.

## When to prefer this

Choose this endpoint when you need lightweight, static HTML parsing specifically targeting footer blocks for invisible Unicode character detection, without JavaScript rendering. It is ideal for security audits, watermark detection, content integrity checks, or phishing analysis where footer anomalies are suspected. Prefer this over general-purpose web scrapers when the task is narrowly scoped to footer element Unicode analysis and cost efficiency ($0.01 USDC per call) is a priority.

## Known failure modes

- URL is unreachable or returns a non-200 HTTP status — parse fails
- Footer element matching the given attribute/value pair not found in the page — empty or null result
- Page requires JavaScript rendering to display footer — static parser returns no footer content
- HTML payload exceeds 100,000 character limit — request rejected
- Attribute value pattern does not match schema regex — validation error
- Rate limiting or payment failure for x402 micropayment — request blocked

## How this service works

Footer blocks — Invisible character flags: Invisible character flags for Footer blocks. 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 invisible character flags result.

## Output

Returns a bounded result indicating which, if any, invisible or hidden Unicode characters (such as zero-width spaces, zero-width non-joiners, soft hyphens, or other non-printable codepoints) are present in the detected footer blocks of the provided URL or HTML. The result is scoped to a specific HTML element identified by attribute and value, and contextualized against a search term and optional previous texts.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "default": "",
   "maxLength": 2048
  },
  "html": {
   "type": "string",
   "default": "<!doctype html><html><head></head><body><footer id=\"sample\" data-kind=\"example\">Example product guide</footer></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/footer-blocks-invisible-character-flags-1b9bb191/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)