# SiteCheck Grammar Checker

> SiteCheck Grammar Checker is a paid API for AI agents from api.sitecheck-api.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-16).

Checks text for grammar and spelling errors, returning annotated issues with suggestions and a corrected version, powered by LanguageTool

## Facts

- Endpoint: POST https://api.sitecheck-api.workers.dev/api/text/grammar?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sitecheck-grammar-checker-d44108ad
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ksQj5Q_R4EgYtkBdSBKGj

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 sitecheck-grammar-checker-d44108ad -d '<json body>'
```

Example prompt: Can you check this paragraph for grammar mistakes and give me the corrected version? 'I has a cat. It sleep all day and never plays with me.' Use US English.

## When to prefer this

Choose this endpoint when you need rule-based grammar and spelling validation with detailed per-error annotations (offset, rule ID, category, suggestions) and an auto-corrected output. It is particularly useful for agents automating content pipelines, proofreading user-generated text, or validating copy before publishing. It supports multiple languages via LanguageTool, making it suitable for multilingual workflows. Prefer it over LLM-based rewriting when you need structured, auditable error reports rather than a free-form rewrite.

## Known failure modes

- Text exceeds 20 KB limit — request rejected
- Unsupported language code returns an error or falls back to auto-detection
- Malformed JSON body causes a 400 error
- LanguageTool upstream API unavailable causes a 502 or timeout
- Empty text field returns zero issues or an error
- Network or payment (x402) failure prevents the call from completing

## How this service works

Grammar, spelling and style check with LanguageTool: each issue with its message, the offending text, its position, up to five suggestions, the rule id and category, plus the corrected text with the first suggestion of each issue applied. Body { text, language }: up to 20 KB, language auto by default. Text is sent only to LanguageTool's public API.

## Output

Returns a JSON object with a count of issues found, an array of issue objects (each with the bad text, its character offset and length, the LanguageTool rule ID, a human-readable message, the error category, and an array of suggested corrections), the detected or specified language, the source API, the timestamp, and a fully corrected version of the input text.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "text": {
   "type": "string",
   "description": "The text to check, up to 20 KB (JSON body field)"
  },
  "language": {
   "type": "string",
   "description": "auto (default), en-US, en-GB, de-DE, fr, es, pt-BR ... as LanguageTool supports them"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "count": 2,
  "issues": [
   {
    "bad": "has",
    "length": 3,
    "offset": 2,
    "ruleId": "BASE_FORM",
    "message": "Possible agreement error — use the base form here.",
    "category": "GRAMMAR",
    "suggestions": [
     "have"
    ]
   },
   {
    "bad": "sleep",
    "length": 5,
    "offset": 16,
    "ruleId": "IT_VBZ",
    "message": "After ‘It’, use the third-person verb form “sleeps”.",
    "category": "GRAMMAR",
    "suggestions": [
     "sleeps"
    ]
   }
  ],
  "source": "LanguageTool public API (api.languagetool.org)",
  "language": "en-US",
  "checkedAt": "2026-10-15T13:48:02.031Z",
  "corrected": "I have a cat. It sleeps all day."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sitecheck-grammar-checker-d44108ad/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.sitecheck-api.workers.dev](https://www.zero.xyz/host/api.sitecheck-api.workers.dev/llms.txt)