DeepSeek AI Detector

Check if text was written by DeepSeek AI. Covers DeepSeek-Coder, V2, R1, V3, and R2 outputs. Free, instant, no login required.

DeepSeek R2 & V3Free Forever70–82% AccuracyNo Login

AI Text Detector

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0 words — 30 minimum for reliable results
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Analyzing…

Narrative Academic
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Signal Breakdown tap to expand

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Accuracy note: Browser-based detectors achieve ~70–80% accuracy. Use as a screening tool, not sole evidence of AI use. How it works →

What Makes DeepSeek Writing Detectable

DeepSeek was trained on technical and academic data, producing formal, step-by-step writing patterns. Reasoning models (R1, R2) show visible chain-of-thought that's uniquely identifiable.

Explicit Step Enumeration

DeepSeek labels reasoning steps: "Step 1:", "Step 2:", "First, I will...", "Next, I will consider..." even in non-technical writing. This structural verbosity reflects its coding and math training data.

Formal Sentence Calibration

DeepSeek defaults to formal register even for casual topics. Contractions are rare; passive voice more frequent than other models. "It is observed that" appears where humans would write "I noticed".

Technical Precision Over Narrative

Numbers, specifications, and precise terms appear even in creative contexts. DeepSeek writes "a 12.4% improvement" where humans write "a noticeable improvement". It can't resist being exact.

Visible Reasoning Chains

DeepSeek R1/R2 show their thinking: "Let me consider...", "On reflection...", "This leads to the conclusion..." — chain-of-thought training artifacts that no human writer produces.

DeepSeek Versions This Covers

Reasoning models (R1, R2) are easiest to detect. Standard models rely on formal register and step enumeration signals.

DeepSeek-Coder (~82%)DeepSeek V2 (~78%)DeepSeek R1 (~75%)DeepSeek V3 (~70%)DeepSeek R2 (~65%)
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Why are R1/R2 easier to detect? Reasoning models include visible chain-of-thought reasoning that human writers never produce. Even when the final answer is clean, reasoning artifacts often remain in the output.

Accuracy & Limitations

DeepSeek scores well overall. Reasoning models score highest due to chain-of-thought artifacts:

Unedited DeepSeek V2 / Coder78–82%
DeepSeek V3 / R170–78%
Human-edited DeepSeek40–58%
Heavily humanized25–42%

DeepSeek Detector FAQ

Yes. DeepSeek produces explicit step enumeration, formal register, and visible reasoning chains — especially R1 and R2. Detection rates of 70–82% on unedited output.
DeepSeek R1/R2 are "thinking" models that show their reasoning process: "Let me consider...", "On reflection...", "This leads to the conclusion..." — patterns that human writers never naturally produce.
Yes. DeepSeek R2 scores ~65% — lower than older models because it improves vocabulary variety, but reasoning chain artifacts and formal register remain detectable.
Yes, completely free. All detection runs as JavaScript in your browser — no server, no API, no login, no word limits.