Model Details
DeepSeek V4 Pro is an open-weight **thinking model** — MIT-licensed, 1.6T total parameters with 49B active per token — built for hard reasoning and code. It reasons before answering, and the brand publishes frontier-tier numbers on the model's own weights repo: **93.5% on LiveCodeBench**, a **3206 Codeforces rating**, **87.5% MMLU-Pro**, **92.6% GSM8K** and **57.9% SimpleQA-Verified**. You send `messages`, you get a chat completion.
The context window is 1,000,000 tokens, and the brand reports it is built to be worked in: at a million tokens the model needs 27% of the per-token inference FLOPs and 10% of the KV cache of the previous generation, which is what makes long-horizon work practical. One response is capped at **393,216 tokens**, and that ceiling is shared — `max_tokens` and the thinking budget draw from the same pool, so a long chain of thought eats the room left for the visible answer.
Thinking effort is set per request with `reasoning_effort`. The documented value set is `low`, `medium`, `high`, `xhigh` and `max`, defaulting to `high`; where a value is accepted, the levels collapse — `low` and `medium` behave exactly like `high`, and `xhigh` behaves like `max` — so there are only two real settings and **no cheap low-effort tier** either way, whether or not the lower values are accepted on this endpoint. Thinking tokens bill as output tokens, so effort and prompt size are both real cost levers.
## Best for - Competitive-programming-grade problems: write the algorithm, then justify its complexity - Hard multi-step reasoning and planning where the model should deliberate before answering - Reading an entire repository or document set in one prompt instead of chunking it - Tool-calling and structured-JSON agent loops that run over many turns - Work that needs open-weight, MIT-licensed capability rather than a closed model
## Choose another model when - Your input includes images, audio, video or PDFs — this model takes text only - You want the cheapest possible tokens for bulk classification, tagging or translation — every request here thinks at `high` or above, and thinking bills as output - A single reply plus its chain of thought has to exceed 393,216 tokens
Served through the OpenAI-compatible chat completions API:
``` POST https://queue.modelrunner.run/deepseek/v4/chat/completions ```
Point any OpenAI SDK or OpenAI-compatible tool at `base_url = https://queue.modelrunner.run/deepseek/v4` with your ModelRunner API key; streaming, tool calling and JSON mode all work.
```js import OpenAI from "openai";
const client = new OpenAI({ apiKey: process.env.MODELRUNNER_API_KEY, baseURL: "https://queue.modelrunner.run/deepseek/v4", });
const result = await client.chat.completions.create({ model: "deepseek/v4", messages: [ { role: "user", content: "Solve this scheduling problem in O(n log n) and prove the bound." }, ], reasoning_effort: "high", max_tokens: 4096, }); ```
Billing is per token from the model's own reported usage, thinking included; repeated prompt prefixes are cached automatically and bill at a steep discount.
