Grammar Checker Template

What it does

Fixes shown in place

Each change is drawn inside your text, with what you wrote crossed out and the fix beside it.

You decide

Take a fix or keep your own wording, one change at a time. Click a change in the text to flip it.

Alternatives on paid plans

When the API returns its corrections list, each change shows the reason and other wordings to choose from.

Draft saved

Your text is kept on the device while you write, so a refresh doesn’t lose it.

Keeps your key private

The browser only talks to your own API route, which caps the text at 5,000 characters, caches answers and limits each visitor to 10 checks a minute.

How it works

The API route: it checks the text, answers from the cache when it can, and calls Grammar Check.

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/** POST /api/check { text }: proofreads a passage and returns the corrected text. */
export async function POST(request: Request) {
  const body = await request.json().catch(() => null);
  const text = String(body?.text ?? '').slice(0, MAX_CHARS);
  if (!text.trim()) return fail('Write or paste some text to check');

  const key = `check:${text}`;
  const hit = fromCache<CheckResult>(key, TTL_MS);
  if (hit) return Response.json(hit);

  const blocked = guard(request);
  if (blocked) return blocked;

  return respond(async () => {
    const data = await callApi<CheckResult>('grammarcheck', { json: { text } });
    toCache(key, data);
    return data;
  });
}

See the whole file on GitHub →

Deploy it

1. Get a free API key

   The free plan includes 200 credits a month, no card needed. Create your key.

2. Deploy it

   Click Deploy to Vercel. Vercel copies the repo to your GitHub account and asks for APIVERVE_API_KEY: paste your key there.

3. Open your app

   Vercel builds it and gives you a live URL, usually in about a minute. Every push to the repo redeploys it.

Try the Grammar Check API — the call this template makes

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{
  "status": "ok",
  "error": null,
  "data": {
    "modified": true,
    "corrected": "The pig snorted when I saw it on the barn gate. I was a little mad because it woke up my puppy",
    "errorCount": 3,
    "dialect": "American",
    "corrections": [
      {
        "rule": "Repetition",
        "message": "Did you mean to repeat this word?",
        "position": {
          "start": 0,
          "end": 7
        },
        "suggestions": [
          "The"
        ]
      },
      {
        "rule": "Spelling",
        "message": "Did you mean `because`?",
        "position": {
          "start": 71,
          "end": 78
        },
        "suggestions": [
          "because"
        ]
      },
      {
        "rule": "Spelling",
        "message": "Did you mean `puppy`?",
        "position": {
          "start": 93,
          "end": 101
        },
        "suggestions": [
          "puppy",
          "puppetry"
        ]
      }
    ]
  }
}