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Synapse Grammar Check
x402
Synapse Grammar Check is a paid API for AI agents from anibalb.duckdns.org, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-31).
Checks input text for grammar and spelling errors, returning a corrected version and a list of individual changes made
Price / call$0.002
Success—
StatusUnknown
How this service works
Public data and utility APIs paid per call in USDC on Base (x402). No accounts, no API keys. 174 routes: crypto/equity data, onchain reads, DNS/email/security intel, geo/weather, x402 payment diagnostics, dev utilities and more.
Output
Returns a JSON object containing a 'corrected' field with the fully corrected text string, and a 'changes' array listing each individual correction made — each item specifies the original token ('from'), the replacement token ('to'), and the type of change (e.g. 'typo').
Example use cases
Proofreading user-submitted content
“Before I publish this blog post excerpt, can you check it for typos and grammar errors and show me exactly what was changed: 'Recieving feedbak from custommers is importent for improveing our prodduct.'”
Validating chatbot response quality
“Check this customer support reply for any spelling or grammar mistakes and give me the corrected version along with a list of every change: 'We apologyze for teh inconveneince and will ressolve you issue shorttly.'”
Cleaning scraped text before storage
“This text was scraped from a form submission and might have typos — can you run a grammar and spelling check on it and tell me what was corrected: 'Pleese shedule a meetting with our managment teem on Thurdsay.'”
Technical details
Endpoint
GEThttps://anibalb.duckdns.org/x402/grammar-check?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a lightweight, pay-per-call grammar and spelling correction API with no account setup — ideal for agents that need to validate or clean short text snippets on demand. It returns structured change-level diffs, making it easy to audit exactly what was corrected. Prefer it over LLM-based proofreading when you want deterministic, auditable corrections rather than free-form rewrites.
Side effects
- Missing or empty 'input' query parameter returns a 400-level error
- Very long text strings may exceed processing limits
- Non-text or non-English content may yield inaccurate or no corrections
- Payment failure or insufficient USDC balance returns 402 Payment Required
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"changes": [
{
"to": "the",
"from": "teh",
"type": "typo"
}
],
"corrected": "the quick brown fox jumps over the lazy dog"
}
}Tags
x402
Reviews
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Zero review prompt (fires after every successful call)
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