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    SupportGPT Proof Deck

    AI Grammar Checker, a free alternative to Grammarly

    Check grammar and spelling in seconds. Instant readability telemetry runs in your browser; Deep proof adds AI fixes. No registration.

    427 / 6,000 chars ยท TXT, MD, HTML, SRT, VTT
    Clarity score
    56

    76 words in 4 sentences. Higher means easier to read: fewer passive, long or repeated phrases.

    9.7
    Grade level
    50%
    Passive
    19.0words
    Avg sentence
    1
    Repeats

    Doubled: can.

    Sentence skyline

    Hover or focus a bar to read its sentence. Click to select it in the editor.

    HealthyOver 30 wordsPassive

    Issue ledger

    Press Deep proof to list grammar, spelling, clarity and tone fixes you can accept one by one. The telemetry above is already live.

    How the proof deck works

    86123
    1Editor

    Paste or drop your draft

    Type or paste up to 6,000 characters, or drop a TXT, MD, HTML, SRT or VTT file. Timing codes and markup are stripped so only your words are checked.

    2Gauges

    Read the telemetry

    Clarity score, grade level, passive voice and the sentence skyline update as you type, so you see exactly which sentences are long, passive or repetitive.

    3Ledger

    Accept the fixes

    Run Deep proof for AI grammar and spelling suggestions. Accept a fix to patch your text, ignore it to move on, then copy or download the corrected version.

    Diagnostics log: common questions

    [00:01]

    Is it really free?

    Yes. The grammar and clarity checker is free, with no registration and no paywalled features. Live readability metrics run in your browser; Deep proof uses an AI model for suggestions.
    [00:02]

    Is my text stored?

    We do not save your text on a server. Live metrics run locally. When you press Deep proof, the draft is sent once to an AI model to generate suggestions.
    [00:03]

    How does it compare to Grammarly?

    It covers the core: grammar, spelling, clarity and tone suggestions with one-click accept, plus a readability dashboard. It has no browser extension or account, and it checks one pasted draft at a time.
    [00:04]

    What limits apply?

    Drafts are limited to 6,000 characters. Longer text is rejected with a message rather than silently cut. Supported files: TXT, MD, HTML, SRT and VTT.
    [00:05]

    Does it work for non-native writers?

    Yes. Each suggestion comes with a short reason, so you learn the rule as you fix it. The tool is tuned for English writing.

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