DeepSeek · DeepSeek Flash line · lightweight · open weights
DeepSeek-V4.1-Flash was released by DeepSeek on September 10, 2026, as an open-weights lightweight model in the DeepSeek Flash line.
A new encoder-decoder design that activates 8B parameters on input and 16B on output, beating V4-Flash-0731 on every agentic test DeepSeek published, with the MIT licence, a 1M-token context and a lower API price than the model it replaces.
Compared with DeepSeek-V4-Flash-0731 · the model it replaces
Finishes 9 in 10 multi-step tasks at the command line
Terminal-Bench 2.1 — running real commands to complete a task
90.6%
▲ up from 82.7% · +8 points
Scores 5 points higher on the all-round intelligence index
Artificial Analysis Intelligence Index v4.3.2 — one score averaging 10 hard tests
39
▲ up from 34 · +5 points
Costs developers less than the model it replaces
Price per 1M tokens — what developers pay, input / output, at peak hours
$0.30 / $1.20
▲ peak hours · down from $0.44 / $1.32 · input 32% cheaper, output 9% cheaper
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DeepSeek-V4.1-Flash-1017 is the current model in this line. The card shows how long it has been since the last release against the line's usual gap and its recent ones — the rhythm, not a date.
Latest: DeepSeek-V4.1-Flash-1017 · Oct 17, 2026
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