DeepSeek V4 Flash

DeepSeek retired V4 Flash on September 10. The legacy `deepseek-v4-flash` name is still accepted for compatibility, but it routes to V4.1 Flash and uses V4.1 Flash pricing. Use the new `deepseek-flash` ID for current hosted work, and use the dated 0731 checkpoint only when you deliberately want the older open model.

• DeepSeek

  The company behind the V4 model family, DeepSeek Chat, public APIs, and open-weight research releases.

The request model remains `deepseek-v4-flash`, but DeepSeek now identifies the backend version as `DeepSeek-V4-Flash-0731`. The company says it keeps the preview model's architecture and size and changes only post-training. The API remains in public beta, while an official MIT-licensed 0731 checkpoint now supersedes the preview weights. V4 Pro and the DeepSeek App/Web models were not upgraded by the API announcement.

• Request model ID: `deepseek-v4-flash`.
• Current API version and official checkpoint: `DeepSeek-V4-Flash-0731`.
• Release status: official API release in public beta, not an unconditional general-availability claim.

The release joined three signals that developers could test immediately: DeepSeek reported a large coding-agent improvement without increasing the model size, Artificial Analysis measured the max-effort model among the leading open-weight models in its class, and existing agent products already exposed the stable V4 Flash endpoint. OpenCode reported V4 Flash as its top model in the latest weekly usage snapshot, but that is platform-specific usage for the V4 Flash line rather than global market share or a clean 0731-only cohort.

• Artificial Analysis reported an Intelligence Index score of 50 and about 103 output tokens per second for the max-effort model on August 6.
• OpenCode reported 58% of observed weekly Go usage for V4 Flash in its August 6 snapshot.
• The stable API model ID and direct availability in coding-agent products reduced migration and trial friction.

Historical 0731 contract: V4 Flash supports the stateless `/responses` endpoint and DeepSeek publishes a Codex provider configuration using `wire_api = "responses"`. The text model accepts messages, reasoning items, function calls, function results, and server-side web-search calls, but not image inputs; multimodal requests require the separate `deepseek-v4-flash-vision-exp` model.

• DeepSeek V4 Flash Vision Exp

  Experimental API-only sibling for mixed text and image input.

• Responses conversations are stateless, so clients resend the full conversation history.
• Reasoning effort maps to low, high, or max behavior; thinking is enabled by default.
• Function tools and server-side web search are supported; image and file inputs are not.

The 0731 model used off-peak rates of $0.007 cache-hit input, $0.22 cache-miss input, and $0.66 output per 1M tokens, with peak rates twice as high. The legacy API ID now routes to V4.1 Flash instead. Current V4.1 Flash rates are lower for cache hits and misses and slightly lower for output, so billing evidence after September 10 should not be attributed to the retired 0731 model.

DeepSeek publishes the official 0731 checkpoint under the MIT License with vLLM and SGLang serving instructions. The model is still large: its official high-performance vLLM example uses a four-GB300 node, so local deployment is primarily a multi-GPU or heavily quantized workflow rather than a routine laptop setup. Choose the hosted API when operational simplicity matters and self-host only when hardware, quantization quality, privacy, or sustained volume justify it.

DeepSeek reports large gains on agent benchmarks, including Terminal Bench 2.1, DeepSWE, Toolathlon verified, and internal DSBench sets. These are vendor-reported results, not independent proof. The public coding-agent runs used an unreleased DeepSeek Harness minimal mode with max effort, top-p 0.95, and temperature 1.0, while two DSBench sets are internal.

The 0731 checkpoint and the launch conditions described above are historical. Today the legacy text Flash ID is a compatibility route to DeepSeek-V4.1-Flash-1017 under deepseek-flash. The current Flash contract supports multimodal input and separate Search/Fetch billing. A successful call through the old ID therefore does not test the original 0731 weights, prices or text-only behavior. Use the current V4.1 guide for a new hosted integration.

• Current official source

  Read the exact release or provider scope.