TokenMix Research Lab · 2026-04-12

DeepSeek API Tutorial 2026: V4 Flash, Pro, Cache Setup Guide

Last Updated: 2026-04-30
Author: TokenMix Research Lab
Data checked: 2026-04-30

Use deepseek-v4-flash as the default DeepSeek API model in 2026. Use deepseek-v4-pro only when a workflow needs harder reasoning, agentic coding, or long-context quality.

The official DeepSeek Models & Pricing page lists V4 Flash at $0.14 per 1M cache-miss input tokens, $0.0028 per 1M cache-hit input tokens, and $0.28 per 1M output tokens. V4 Pro is discounted to $0.435 cache-miss input, $0.003625 cache-hit input, and $0.87 output until 2026-05-31 15:59 UTC. DeepSeek also says deepseek-chat and deepseek-reasoner currently map to V4 Flash compatibility modes and will be deprecated.

Table of Contents

• Quick Setup
• Confirmed Facts
• Current Models And Prices
• Python Setup
• Node.js Setup
• Thinking Mode
• Context Caching
• Migration From Old Model Names
• Production Checks
• When TokenMix.ai Fits
• FAQ
• Related Articles
• Sources

Quick Setup

For most apps, the first production route is V4 Flash. It is the economical route, supports 1M context, and uses the same OpenAI Chat Completions pattern.

Confirmed Facts

Current Models And Prices

All prices are per 1M tokens, checked on 2026-04-30.

Do not price new DeepSeek projects with old R1 or V3.2 assumptions. The current official table is V4-first.

Python Setup

Install the OpenAI SDK:

pip install openai

Use DeepSeek with an OpenAI-compatible client:

from openai import OpenAI

client = OpenAI(
    api_key="DEEPSEEK_API_KEY",
    base_url="https://api.deepseek.com"
)

response = client.chat.completions.create(
    model="deepseek-v4-flash",
    messages=[
        {"role": "system", "content": "You are a precise technical assistant."},
        {"role": "user", "content": "Summarize this bug report in 3 bullets."}
    ]
)

print(response.choices[0].message.content)

Use V4 Pro only after the Flash result fails a real quality threshold:

response = client.chat.completions.create(
    model="deepseek-v4-pro",
    messages=[
        {"role": "user", "content": "Analyze this refactor plan and identify the riskiest dependency."}
    ]
)

Node.js Setup

Install the SDK:

npm install openai

Call V4 Flash:

import OpenAI from "openai";

const client = new OpenAI({
  apiKey: process.env.DEEPSEEK_API_KEY,
  baseURL: "https://api.deepseek.com"
});

const response = await client.chat.completions.create({
  model: "deepseek-v4-flash",
  messages: [
    { role: "user", content: "Classify this support ticket as low, medium, or high priority." }
  ]
});

console.log(response.choices[0].message.content);

Thinking Mode

DeepSeek V4 supports thinking and non-thinking modes. The old model name deepseek-reasoner currently maps to V4 Flash thinking mode, but DeepSeek says old aliases will be deprecated. New code should choose explicit V4 model names and mode settings according to the current docs.

Context Caching

DeepSeek context caching is enabled by default. The official docs say overlapping prefixes can be fetched from disk cache and billed as cache hits.

Example cost for 1M repeated input tokens on V4 Flash:

Migration From Old Model Names

DeepSeek says deepseek-chat and deepseek-reasoner will be retired after 2026-07-24 15:59 UTC. Do not wait for the deadline if your app is in production.

Production Checks

When TokenMix.ai Fits

Use direct DeepSeek when you only need DeepSeek and want the official account relationship. Use TokenMix.ai when DeepSeek is one route inside a broader production stack with OpenAI, Claude, Gemini, Qwen, Grok, or Kimi.

FAQ

What is the current DeepSeek API model to use?

Use deepseek-v4-flash first. It is the economical V4 route and supports 1M context, tool calls, JSON output, and thinking or non-thinking modes.

How much does DeepSeek V4 Flash cost?

DeepSeek V4 Flash costs $0.0028 per 1M cache-hit input tokens, $0.14 per 1M cache-miss input tokens, and $0.28 per 1M output tokens.

How much does DeepSeek V4 Pro cost?

V4 Pro is discounted to $0.003625 cache-hit input, $0.435 cache-miss input, and $0.87 output per 1M tokens until 2026-05-31 15:59 UTC.

Should I still use deepseek-chat?

No for new code. DeepSeek says deepseek-chat currently maps to V4 Flash non-thinking mode and will be deprecated. Use explicit V4 model names.

Should I still use deepseek-reasoner?

No for new code. deepseek-reasoner currently maps to V4 Flash thinking mode, but new applications should use explicit V4 naming and mode controls.

Does DeepSeek cache require code changes?

No for basic usage. DeepSeek says context caching is enabled by default. You should still log prompt_cache_hit_tokens and prompt_cache_miss_tokens.

Is DeepSeek OpenAI-compatible?

Yes. DeepSeek lists an OpenAI-format base URL at https://api.deepseek.com, so the standard OpenAI SDK pattern works.

When should I use TokenMix.ai instead of direct DeepSeek?

Use TokenMix.ai when you need DeepSeek plus other providers, fallback routing, unified billing, or local payment methods such as Alipay and WeChat Pay.

Related Articles

• DeepSeek Cache Hit Pricing 2026: V4 98% Input Savings Guide

• DeepSeek API Pricing 2026: V4 Costs, Cache Hits, R1 Changes

• AI API Pricing 2026: 16 Models, Cache, Batch, Routing Hub

• OpenAI vs DeepSeek Cost 2026

• LLM API Gateway Guide

• OpenAI-Compatible API Gateway

• Best OpenRouter Alternatives 2026

• AI API With WeChat Pay

Sources

• DeepSeek Models & Pricing
• DeepSeek V4 Preview Release
• DeepSeek Context Caching
• DeepSeek Anthropic API compatibility
• TokenMix.ai DeepSeek API pricing guide