POST Grammar Fix API
/api/v1/ai/grammar-fix
Automatically correct spelling, grammar, and punctuation while giving developers full control over tone and dialect.
Architecture Role & AI Definition
Grammar Fix API provides low-latency, deterministic REST execution for production engineering workflows. It processes structured payloads with strict schema validation, returns uniform JSON envelopes, and is secured via SHA-256 API key authentication with atomic credit pre-authorization locks.
Production Reliability Guidelines
Configure a hard client timeout of 5 to 8 seconds. If network latency spikes, cancel connection to avoid holding open sockets in worker pools.
Upon receiving 429 Rate Limit or transient 5xx, pause with exponential backoff:
wait = min(max_backoff, base * 2^attempt + jitter).
RSFlowHub acquires an atomic lock verifying base credits before model invocation. If validation fails, zero credits are deducted.
Request Body Parameters
| Field | Type | Required | Description |
|---|---|---|---|
text |
string | Required | The raw text to be corrected (Max: 5,000 characters). |
tone |
string | Optional | Desired tone of the corrected text (e.g., "professional", "casual", "academic"). Default is "auto" (keeps original tone). |
dialect |
string | Optional | Target English dialect (e.g., "US", "UK", "AU"). Adjusts localized spellings like color vs colour. Default is "US". |
return_explanations |
boolean | Optional | Optional. If true, the API will return an array detailing exactly what was changed and why (similar to Grammarly). |
Example Request (with Explanations)
This example demonstrates how to pass poorly written text and receive a heavily corrected version back with detailed explanations.
{
"text": "I went to the store yesterday bcuz I need milk. the cashier was rude to me.",
"tone": "professional",
"dialect": "US",
"return_explanations": true
}curl -X POST https://rsflowhub.com/api/v1/ai/grammar-fix \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"text": "I went to the store yesterday bcuz I need milk. the cashier was rude to me.",
"tone": "professional",
"dialect": "US",
"return_explanations": true
}'Example Response
The response provides the cleanly rewritten text alongside the `explanations` array, which maps out every single grammar and tonal fix.
{
"success": true,
"request_id": "req_7f3a9c2d1e4b8a6f",
"data": {
"result": {
"corrected_text": "I went to the store yesterday because I needed milk. The cashier was impolite to me.",
"changes_made": true,
"explanations": [
{
"original": "bcuz",
"corrected": "because",
"reason": "Corrected informal slang to standard spelling."
},
{
"original": "need",
"corrected": "needed",
"reason": "Adjusted verb tense to match the past tense context of 'yesterday'."
},
{
"original": "the",
"corrected": "The",
"reason": "Capitalized the first letter of the sentence."
},
{
"original": "rude",
"corrected": "impolite",
"reason": "Adjusted vocabulary to sound more professional."
}
]
}
},
"meta": {
"version": "v1",
"timestamp": "2026-09-27T12:34:56+00:00"
}
}API Request Example
Use the cURL snippet below to test the endpoint.
curl -X POST 'https://rsflowhub.com/api/v1/ai/grammar-fix' \
-H 'Authorization: Bearer YOUR_API_KEY' \
-H 'Content-Type: application/json' \
-d '{
"text": "I went to the store yesterday bcuz I need milk.",
"return_explanations": true
}'Want to try it without code? Test this request in the live Playground.
Common Failure Modes & Troubleshooting Matrix
| HTTP Code | Error Code | Root Cause | Recommended Remediation |
|---|---|---|---|
| 401 | API_KEY_MISSING / INVALID_API_KEY |
No key sent, or the key was mistyped or regenerated. | Copy the current key from Dashboard → API Keys and send it as Authorization: Bearer (or X-API-Key). |
| 402 | INSUFFICIENT_CREDITS |
Your balance cannot cover the estimate for this call (base 1 credits plus input/output size). | Buy a plan in Dashboard → Billing. Nothing was charged. |
| 422 | VALIDATION_ERROR |
A field is missing, too long or the wrong type, or the body is not valid JSON. | Read error.details for the field messages and fix the request. Do not retry the same body. |
| 429 | RATE_LIMIT_EXCEEDED |
Your plan-wide or per-endpoint per-minute limit was reached. | Wait the seconds in the Retry-After header, then retry with jitter. Rate limits |
| 502 | AI_PROVIDER_ERROR |
The AI model and its backup both failed. | Retry with backoff and check the status page. Nothing was charged. |