# Causal Encoder-Decoder (CED) architecture

DeepSeek released the October 17, 2026 snapshot of V4.1 Flash, served under the deepseek-flash API model name. It is the company's first sparse mixture-of-experts model built on its Causal Encoder-Decoder architecture, activating 8B parameters on input and 16B on output from a 552B backbone, with image understanding trained jointly with text from the start of pretraining rather than added afterward. Compressed KV caching cuts cache memory to roughly a quarter of the previous Flash generation, and DeepSeek reports it exceeds V4 Pro on performance, speed and task completion time.

DeepSeek released the October 17, 2026 snapshot of V4.1 Flash, served under the deepseek-flash API model name. It is the company's first sparse mixture-of-experts model built on its Causal Encoder-Decoder architecture, activating 8B parameters on input and 16B on output from a 552B backbone, with image understanding trained jointly with text from the start of pretraining rather than added afterward. Compressed KV caching cuts cache memory to roughly a quarter of the previous Flash generation, and DeepSeek reports it exceeds V4 Pro on performance, speed and task completion time.