Grammar Fix API Specification & Integration Reference
API Endpoint Public API Page

POST Grammar Fix API

/api/v1/ai/grammar-fix

Automatically correct spelling, grammar, and punctuation while giving developers full control over tone and dialect.

Base Billing 1 Credit
Target Latency < 150ms (p50)
Client Timeout 5.0s (recommended)
SLA Guarantee 99.9% Uptime
JSON Contract Deterministic v1

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

1. Strict Timeout Windows

Configure a hard client timeout of 5 to 8 seconds. If network latency spikes, cancel connection to avoid holding open sockets in worker pools.

2. Exponential Backoff with Jitter

Upon receiving 429 Rate Limit or transient 5xx, pause with exponential backoff:
wait = min(max_backoff, base * 2^attempt + jitter).

3. Atomic Pre-Auth Locks

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).
model string Optional Optional AI model to use.

Example Request (with Explanations)

This example demonstrates how to pass poorly written text and receive a heavily corrected version back with detailed explanations.

JSON Request 
{
  "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-trigger.sh cURL 
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.

response.json JSON Response
200 OK 118ms 
{
  "success": true,
  "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": {
    "credits_used": 1,
    "credits_remaining": 990
  }
}

API Request Example

Use the cURL snippet below to test the endpoint.

curl-trigger.sh cURL 
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
}'

Common Failure Modes & Troubleshooting Matrix

HTTP Code Error Code Root Cause Recommended Remediation
400 bad_request Malformed JSON syntax or missing required top-level parameters. Validate JSON payload with Content-Type: application/json and ensure all required fields are present.
401 unauthorized Missing, revoked, or incorrectly formatted x-api-key header. Verify API key exists in Dashboard → API Keys and pass in x-api-key or Authorization: Bearer.
402 insufficient_credits Account credit balance is lower than the base required credits (1 credits). Top up credits in billing settings or enable auto-recharge to prevent pipeline interruption.
422 validation_error Input failed parameter constraints (e.g., character length exceeded or invalid array types). Review parameters table above and adjust payload length, types, or structure accordingly.
429 rate_limit_exceeded Concurrency limit (60 requests/minute default) reached for this endpoint key. Back off and retry using the timestamp in Retry-After response header, or batch requests.

Technical Q&A (FAQ)

We recommend setting a client timeout of 5 to 8 seconds. While average latency is under 150ms, large input payloads or complex reasoning models may require additional processing time.

RSFlowHub uses an atomic pre-flight check. Before processing, the gateway validates that your wallet has at least 1 base credits. If the request fails validation (422) or is malformed (400), no credits are charged.

When a 429 is received, your application should respect the 'Retry-After' header and use an exponential backoff retry policy with randomized jitter to prevent thundering herd problems.

Every successful response returns { "success": true, "data": { ... }, "meta": { "credits_used": int, "credits_remaining": int } }.

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