DeepSeek V4.1 Flash takes over from V4 Flash at a lower price
DeepSeek released DeepSeek-V4.1-Flash on 10 September 2026[1]. On the API it is called deepseek-flash[2].
It is a 552B-parameter mixture-of-experts model that activates 8B parameters while reading input and 16B while writing output[1,3]. It takes images as well as text[1,3]. The weights are on Hugging Face under the MIT License[3].
The context window is 1 million tokens, and one response can run to 384K tokens[2].
With the release, V4 Flash and V4 Flash Vision Exp were retired[1,2]. Requests sent under the names deepseek-v4-flash and deepseek-v4-flash-vision-exp are served by V4.1 Flash and billed at the Flash price[2].
The change log says API prices were reduced along with the release[4]. The new rates took effect at 04:00 UTC on 10 September[1].
Per million tokens off-peak, input that hits the cache is $0.003, input that misses it is $0.15, and output is $0.60[2]. From 01:00 to 04:00 and 06:00 to 10:00 UTC on weekdays the peak rate applies, and every figure doubles[1,2].
The announcement said that from 04:00 UTC on 14 September every deepseek-v4-pro request would be routed to V4.1 Flash and billed at V4.1 Flash rates[1].
The change log and the pricing page now say that, in response to user demand, DeepSeek will keep serving V4 Pro after 14 September with billing unchanged[2,4]. V4 Pro is $0.022, $0.66 and $1.98 off-peak, and double that at peak[2].
DeepSeek says V4.1 Flash scores ahead of flagship models including V4 Pro[1].
Setting the two side by side at maximum reasoning effort, the model card has V4.1 Flash ahead on DeepSWE v1.1, 74.2 against 62.7, and on Terminal-Bench 2.1, 90.6 against 87.9[3]. On GPQA Diamond V4 Pro is higher, at 92.4 against 90.9[3].