# DeepSeek V4 Pro - Core.Today AI API

> DeepSeek's strongest V4 model (checkpoint V4-Pro-0813). Advanced reasoning with thinking mode on by default, a 1M-token context window, and discounted cache reads - still far cheaper than comparable frontier models.

- **Provider**: DeepSeek
- **Model ID**: deepseek-v4-pro
- **Category**: LLM
- **Credits**: 1.2 per 1K tokens (avg)
- **Speed**: Medium
- **Quality**: Ultra

## Model Specifications
- **Context Window**: 1.0M tokens
- **Max Output**: 384K tokens
- **Training Cutoff**: 2025-05
- **Supported Formats**: text, json, markdown
- **Compatible SDK**: OpenAI

### Capabilities
- Function Calling
- Streaming
- JSON Mode
- System Prompt

### Token Pricing (per 1M tokens)
- **Input Tokens**: 808 credits ($0.54)
- **Output Tokens**: 1,616 credits ($1.08)
- **Cached Tokens**: 6.7 credits ($0.00)

## Features
- Strongest reasoning in the DeepSeek family
- 1M context window, up to 384K output tokens
- Thinking mode on by default (switchable per request)
- OpenAI-compatible API (chat completions)
- Context cache hits billed at a steep discount

## Use Cases
- Complex reasoning, math, and code generation
- Long-document analysis with the 1M context
- Cost-efficient alternative to frontier reasoning models

## API Endpoint

Base URL: https://api.core.today
Endpoint: POST /llm/deepseek/v1/chat/completions

## Authentication
Header: Authorization: Bearer YOUR_API_KEY

Note: LLM endpoints use OpenAI-compatible format with Authorization Bearer token.

## Input Parameters

### Required
- **model**: string - Model ID, e.g. "deepseek-v4-pro".
- **messages**: array - Chat messages in OpenAI format (system/user/assistant roles).

### Optional
- **temperature**: number (default: 0.7) - Sampling temperature (0-2).
- **max_tokens**: integer (default: 2048) - Maximum completion tokens.
- **stream**: boolean (default: false) - Stream the response as server-sent events.

## Examples

### Chat completion
OpenAI-compatible chat completion request
```json
{
  "model": "deepseek-v4-pro",
  "messages": [
    {
      "role": "user",
      "content": "Prove that the sum of two even numbers is even."
    }
  ],
  "max_tokens": 2048
}
```

## Response Format
```json
{
  "id": "chatcmpl-abc123",
  "object": "chat.completion",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "Response text here"
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 100,
    "completion_tokens": 50,
    "total_tokens": 150
  }
}
```

## Tips
- Works with the OpenAI SDK - set base_url to https://ai.api.core.today/llm/deepseek/v1
- Thinking mode is on by default - disable it per request for latency-sensitive calls
- Cache hits are billed at a steep discount - reuse long system prompts and shared prefixes
- Anthropic-format endpoint is not supported through the gateway - use the OpenAI format

## Documentation
https://api-docs.deepseek.com/