DeepSeek V4 Pro
DeepSeek V4 Pro: the senior V4 for hard coding and reasoning, 1M context.
First request
from openai import OpenAI
client = OpenAI(
base_url="https://api.altrouter.ai/v1",
api_key="ar-...",
)
resp = client.chat.completions.create(
model="deepseek-v4-pro",
messages=[{"role": "user", "content": "Hello!"}],
)
print(resp.choices[0].message.content)import OpenAI from "openai";
const client = new OpenAI({
baseURL: "https://api.altrouter.ai/v1",
apiKey: process.env.ALTROUTER_API_KEY, // ar-...
});
const resp = await client.chat.completions.create({
model: "deepseek-v4-pro",
messages: [{ role: "user", content: "Hello!" }],
});
console.log(resp.choices[0].message.content);curl https://api.altrouter.ai/v1/chat/completions \
-H "Authorization: Bearer ar-..." \
-H "Content-Type: application/json" \
-d '{
"model": "deepseek-v4-pro",
"messages": [
{
"role": "user",
"content": "Hello!"
}
]
}'The interface is OpenAI-compatible: in existing code only the base_url, the key and the model id change — nothing else.
DeepSeek V4 Pro against its price neighbours
| Model | Input / 1M | Output / 1M | Context | |
|---|---|---|---|---|
| GPT-5.4 nanoOpenAI | $0.25 | $1.55 | 400K | Open |
| Gemini 3.5 Flash LiteGoogle | $0.27 | $2.25 | 1.0M | Open |
| DeepSeek V4 Prothis pageDeepSeek | $0.93 | $2.80 | 1M | |
| Gemini 3.8 FlashGoogle | $0.64 | $3.19 | 1M | Open |
| Grok 4.7xAI | $1.70 | $5.10 | 500K | Open |
Prices and parameters come from the same catalog as the price above; this is not a benchmark, it is comparable billing terms.
Limits
Context is 1M tokens per request, and it holds everything you send: the system prompt, the conversation history and the current question together. Whatever does not fit is not seen by the model — trimming the history is your side of the job, and you pay for exactly what fit.
Response length is set by max_tokens, capped at 32,000 tokens per call. A response that hits the cap comes back with finish_reason: "length" — truncated but still billed, so it is worth setting deliberately on long generations.
Supported: a reasoning mode, tool calling, image input.
There is no subscription: every successful request is billed at the price above, and a failed one is not billed at all. There is no markup over the vendor's official price. No DeepSeek account of your own is needed: requests go to api.altrouter.ai and we make the upstream call.
Rate limiting is shared across models and counted per key: 600 requests per minute by default, and a 429 with retry-after: 60 above it. An individual key can get its own limit and a spending cap per day, week, month or lifetime in the dashboard.
When to pick DeepSeek V4 Pro, and when a neighbour
The cheaper neighbour is Gemini 3.5 Flash Lite: $0.27 per 1M input tokens against $0.93 for DeepSeek V4 Pro. On the same volume the bill comes out 3.5× smaller. Its context is even larger: 1.0M against 1M. It is the sensible pick where the task is repetitive and high-volume — labelling, classification, short templated answers — the kind of work where quality is bounded by the prompt rather than the model.
The dearer neighbour is Gemini 3.8 Flash: $0.64 per 1M input tokens. On catalog parameters it offers the same capabilities and the same order of context, so the premium is only justified if DeepSeek V4 Pro falls short on your own task.
Guessing is more expensive than checking: the table above is prices and parameters, not a benchmark, and it cannot tell you which model does better on your own prompt. Switching costs one line — the model id in the request changes, the base_url and the key stay — so running both on your own data takes minutes.
OpenAI-compatible chat completions endpoint, with SSE streaming.
/v1/chat/completionsStructured fields (tools, response_format, stop and more) are in the full parameter reference.