About

Just Human was built to solve a simple problem: in a world of AI-generated text, how do you show that you actually wrote something?

We record every keystroke, pause, and correction as you type, then turn it into a shareable replay. Anyone who clicks the link can watch your writing process unfold in real time -the thinking, the hesitation, the rewording. Things a machine doesn't do.

Why it matters

There's something happening to words. Every day, billions of them are generated instantly - polished, grammatically flawless, and utterly without effort. They arrive fully formed, with no crossed-out phrases, no pauses where someone searched for the right way to say something, no moments of doubt. They are perfect, and that perfection is exactly the problem.

Being human has never been about getting it right on the first try. It's about the backspace. The sentence you rewrote three times because it didn't quite capture what you meant. The long pause where you stared at the screen, thinking. The typo you caught - or didn't. These aren't flaws in your writing. They're proof that someone was actually there, wrestling with an idea, trying to make it honest. A machine can produce text, but it cannot hesitate. It cannot change its mind. It cannot care whether the words are true.

We built Just Human because we believe the process matters as much as the result. When you share a replay of your writing, you're not just sharing words - you're sharing evidence of thought. Every correction is a small act of integrity, every pause a moment of genuine reflection. In a world that's increasingly flooded with effortless content, the courage to show your rough edges might be the most human thing you can do.

By the numbers

How Analysis works

When you open a replay, the Analysis panel scores how human the writing process looks. It examines nine independent signals from the keystroke data and combines them into a single 0–100 score. A higher score means the pattern is more consistent with real-time human typing.

Rhythm Variability

Humans don't type at a constant speed. This metric measures how much the gap between keystrokes varies - too uniform suggests a machine, while natural variation signals a real person.

Error Corrections

Backspaces and quick typo-fix sequences are a hallmark of human writing. The score looks at how often corrections happen and whether they follow the rapid delete-retype pattern people use instinctively.

Paste Content

Measures how much of the final text was pasted in rather than typed character by character. Small pastes (a URL, a name) are normal. When pasted content heavily outweighs actual typing, the score drops sharply - text that was mostly pasted in with little manual writing is a strong signal of machine-generated content.

Think Pauses

People stop to think - between sentences, before a tricky word, after re-reading what they wrote. This metric checks for natural thinking breaks and whether they fall near sentence boundaries.

Timing Distribution

Human keystroke timing tends to follow a log-normal distribution: most gaps are short, with a long tail of slower ones. This signal checks whether the overall statistical shape matches that expectation.

Digraph Timing

When you type the same pair of letters repeatedly (e.g. “th” or “er”), your fingers take roughly the same time each time because of muscle memory. This metric checks whether repeated character pairs have consistent timing, and whether physically distant keys take longer than adjacent ones - a biomechanical pattern that automation tools do not reproduce.

Dwell Time

Dwell time is how long a key is held down before being released. Humans typically hold keys for 50–200 milliseconds with natural variation across fingers - pinkies tend to be slower than index fingers. Browser automation tools like Playwright produce near-zero dwell times (0–2ms), making this a strong signal.

Burst-Pause Patterns

People type in bursts that roughly correspond to words, with short pauses between them. This metric checks whether the recording shows natural word-level clustering, and whether pauses tend to fall at word and sentence boundaries rather than being randomly distributed.

Fatigue

Over the course of a writing session, humans gradually slow down and make slightly more errors. This metric divides the recording into quarters and checks for the subtle speed decrease and error-rate increase that characterise real fatigue.

Scores fall into three tiers. Above 80 earns a “Written by a human” badge with a blue social preview. Between 50 and 80 the result is uncertain - the preview uses a neutral amber tone. Below 50, the analysis suggests the input may be automated, shown with a muted red preview. If a recording is too short to analyze - fewer than 30 events or under 5 seconds - it receives a neutral slate preview instead of being scored. In every case the full replay remains viewable.

No algorithm can definitively prove authorship. Dictation software, accessibility tools, and mobile keyboards may produce unusual patterns that lower scores. These signals are indicators, not guarantees - the replay itself is always the strongest evidence.

Anti-bot defenses

Just Human exists to show that a person wrote something, so we take automated submissions seriously. We use several layers of defense to raise the cost of faking a recording. Here is exactly what we do.

Event integrity verification

When you submit a recording, the server replays every event from scratch and verifies that the result matches your final text. If the events don't reproduce the text, the submission is rejected. Duration and character count are computed server-side from the events themselves - we don't trust client-supplied metadata.

Rate limiting

Submissions are limited to 20 per hour and 40 per day per IP address. We store a SHA-256 hash of your IP combined with a daily rotating salt - we never store your raw IP address. Rate limit records are automatically deleted after 24 hours.

Browser environment checks

When you submit, we collect signals from your browser environment: whether navigator.webdriver is set (a flag present in Playwright, Puppeteer, and Selenium by default), whether Playwright-specific global variables exist, how many browser plugins and languages are configured, and whether the window.chrome object is present. None of these signals block your submission - they contribute to the confidence level of the analysis.

Typing biometrics

Beyond the timing between keystrokes, we record two additional signals: dwell time (how long each key is held down) and flight time (the gap between releasing one key and pressing the next). We also record which physical key was pressed (e.g. the KeyH key, not just the letter “h”). These signals enable digraph analysis and per-finger dwell comparisons that are extremely difficult for automation tools to fake convincingly.

Session telemetry

During your writing session, we count (but do not record the content or positions of) mouse movements, scroll events, touch events, textarea focus/blur events, and page visibility changes. These counts are stored with your recording. A five-minute writing session with zero mouse movement is unusual for a human; these signals help calibrate confidence.

Server-side scoring

Analysis is run on the server at submission time and stored alongside the recording. This means the score you see on a replay was computed from the raw events by our server, not by your browser. The stored analysis includes the overall score, confidence level, per-metric breakdown, and any flags (such as “zero dwell times detected” or “webdriver flag present”).

What we never do: We never reject a recording based on its analysis score. Low-scoring recordings are saved and remain viewable - the score is shown honestly to anyone who views the replay. Our goal is transparency, not gatekeeping.

A sufficiently sophisticated bot can defeat any behavioral analysis. These defenses raise the cost of attack from “a single prompt” to “build a biomechanical typing simulator.” Perfect detection is not the goal - honest confidence levels are.

Chrome Extension

The Just Human Chrome extension lets you record directly on X.com - no switching tabs, no copy-pasting. It attaches to the compose box, records your keystrokes as you type, and automatically appends a proof link when you post.

Built by

Dynamic Strategies

Development & research firm building tools at the intersection of finance, technology, and the open web.

dynamicstrategies.io →

Get in touch

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