Master The New_
The complete, step-by-step tutorial directory for DeepSeek V4 Flash. Learn how to access official APIs, optimize costs, and connect LLMs to your apps — simplified for everyone. An independent fan-made resource, not run by DeepSeek.
DeepSeek Harness Developer Preview
DeepSeek's official agent framework — open source since Aug 13, 2026. The “Model + Harness = Agent” runtime where every capability is a plugin: models, tools, sandboxes, and even the agent loop itself. Model-agnostic, MIT-licensed, and directly positioned against Claude Code.
Shipped Aug 13, 2026 — source code open on the same day
127K GitHub stars in 3 days · github.com/deepseek-ai/deepseek-harness
Everything is a plugin — models, tools, sandboxes, even the agent loop
From full coding agent to two-tool benchmark mode — pick in config
FEATURED GUIDES & TUTORIALS
34 ARTICLESWhat Is DeepSeek V4.1 Flash? The 552B MoE, Explained
The Sept 10, 2026 release: a 552B MoE with native vision, 8B/16B asymmetric activation, a 1M context, and an 890-byte-per-token KV cache.
DeepSeek V4.1 Flash Pricing: $0.003 Cache Hits & Peak Rates
$0.003 per 1M cached input tokens off-peak, $0.15 uncached, $0.60 output. Peak/off-peak table, cache math, and how it compares to GPT and Claude.
DeepSeek V4.1 Flash Benchmarks: Full Official Table
Every official score: Terminal-Bench 2.1 90.6, DeepSWE 74.2, CyberGym 88.1, plus the multi-scaffold table and the effort-cost caveat.
DeepSeek V4.1 Flash API Setup: Base URL, Model ID & Migration
Set model to deepseek-flash, keep your base URL, and migrate from old names. Includes a first curl call and reasoning-effort parameters.
DeepSeek V4.1 Flash Vision: Native Multimodal Images
Native image understanding via a 32-layer DeepSeek-ViT: MMMU-Pro 56.5, DocVQA 95.6, and visual-agent scores, replacing V4-Flash-Vision-Exp.
DeepSeek V4.1 Flash Reasoning Effort: The 1-100 Dial Explained
A continuous 1-100 effort scale, not just low/high/max. How the setting trades 2.5x output tokens for accuracy, and how to pick a level.
DeepSeek Model Names & Retired IDs: The 2026 Alias Reference
Every DeepSeek model id, alias, and retirement status in one table — so a rerouted or deprecated name never breaks production.
DeepSeek V4.1 Flash vs V4 Flash: 552B, CED & the 94% Jump
The 94% backbone jump from 284B to 552B, the move from 13B to 8B/16B activation, a 4x smaller KV cache, and what it means for migration.
DeepSeek V4.1 Flash vs Claude Opus 5: DeepSWE & the Cost Gap
DeepSWE 74.2 vs 74.0 and CyberGym 88.1 vs none — but Opus 5 wins the harder Terminal-Bench 3.0/4.0. Open weights at a fraction of the price.
DeepSeek V4.1 Flash vs Kimi K3: The Open-Weight Duel
Two open-weight rivals compared: V4.1 Flash leads on agent and coding tests, Kimi K3 leads GPQA and HLE. Pricing and cache rates compared.
DeepSeek V4.1 Pro: What We Know So Far
DeepSeek's next flagship has no release date. What the CED family implies, why V4-Pro traffic routes to Flash until it ships, and how to track it.
Run DeepSeek V4.1 Flash Locally: VRAM, vLLM & Quantization
Download the MIT weights and serve them with vLLM: a 511 GB checkpoint, a 614 GB VRAM floor, GB200/H200 layouts, and DSpark.
DeepSeek V4.1 Flash for Coding Agents: OpenCode, Claude Code & Harness
Official setup for Claude Code, OpenCode, and OpenClaw, plus the DeepSeek Harness minimal mode used for the official agent benchmarks.
DeepSeek V4.1 Flash KV Cache: 890 Bytes per Token Explained
How V4.1 Flash stores its KV cache in 890 bytes per token: CED projection, CSA2 layer modes, FP4 KV, SWA Bounded Replay, and the 72-hour cache.
DeepSeek V4 Pro Retired: Why It Routes to V4.1 Flash
From Sept 14, 2026, every deepseek-v4-pro request routes to V4.1 Flash at Flash rates. The timeline, official reasons, and developer pushback.
What Is DeepSeek V4 Flash? Full Guide to the 0731 Release
A 284B-parameter open-weight MoE with 1M context. What the July 31, 2026 official release actually changed versus the preview.
DeepSeek V4 Flash API Setup: Base URL, Models & Your First Call
Step-by-step: create an API key, set the base URL, and make your first call with curl, Python, or Node.js.
DeepSeek V4 Flash Pricing: Token Costs & How to Save (Aug 2026)
Official token pricing ($0.14 / $0.28 per 1M), the ~98% context-cache discount, and real savings vs GPT-5.5 and Claude.
DeepSeek V4 Flash Benchmarks: Agentic & Coding Scores in 2026
All nine official agentic benchmarks, the +645% DeepSWE jump, and how V4 Flash stacks up against GLM-5.2 and Opus-4.8.
Use DeepSeek V4 Flash with OpenCode: Step-by-Step
Connect the open-source OpenCode agent to DeepSeek V4 Flash in minutes with the official /connect deepseek flow.
DeepSeek V4 Flash in Cursor, Claude Code & Codex: Setup Guide
Configure DeepSeek V4 Flash in Cursor, Claude Code (ANTHROPIC_BASE_URL), and Codex with the official one-click script.
DeepSeek V4 Flash on OpenRouter: Setup, Pricing & BYOK
Two model slugs, third-party pricing, BYOK setup, and when to route through OpenRouter instead of the official API.
DeepSeek V4 Flash Model Size: Params, VRAM & What It Means
284B total / 13B active explained, weight sizes in FP4/FP8/BF16, and what GPU you actually need to run it.
Download DeepSeek V4 Flash from HuggingFace & Run It Locally
Download the MIT-licensed DeepSeek-V4-Flash-0731 weights from HuggingFace and serve them with vLLM.
DeepSeek V4 Pro: GA Release, Pricing & Benchmarks (0813)
1.6T-parameter flagship still in preview. Specs, official pricing, self-reported benchmarks, and the expected release window.
Why DeepSeek V4 Is the Best Cheap AI Right Now: A Beginner Guide
Don't know model names? Here's why DeepSeek V4 is the best cheap AI to start with — plain-English, with honest limitations.
OpenCode Go: The $5/Month Subscription That Unlocks DeepSeek V4
The $5/month subscription that unlocks DeepSeek V4 Flash and Pro — roughly 158K Flash requests a month for $10.
Connect Claude Code & Claude Desktop to DeepSeek V4 with CC Switch
Point Claude Code & Claude Desktop at DeepSeek V4 using CC Switch — official env vars, Desktop dev mode, and Linux setup.
DeepSeek Harness: Release, Install & Plugin Guide
DeepSeek's official agent framework is unreleased but every benchmark was measured on it. Everything we know so far.
DeepSeek V4 Technical Report Explained: Architecture & Benchmarks
A guided tour of the DeepSeek V4 paper — CSA+HCA attention, Muon, 27% of V3.2's FLOPs, and how to read the model cards.
Why a Native Harness Makes AI Agents Dramatically Better
Why 'Model + Harness = Agent' — the context management, tool loops, and self-correction that turn a raw model into a real agent.
Reasonix: The DeepSeek Harness That Hits 99%+ Cache Rates
Reasonix hits 99%+ DeepSeek cache rates — 435M input tokens for $1.38 instead of $61. How the cache-first loop saves ~98%.
Hermes Best Setup: DeepSeek V4 Flash 0731 + MiMo V2.5 (Vision)
The community-verified best pairing for Hermes: DeepSeek V4 Flash 0731 as the text brain + MiMo V2.5 for vision.
DeepSeek V4 vs GPT-5.6 Luna: Which Is Better After the Price Cut?
DeepSeek V4 Flash vs the price-cut GPT-5.6 Luna: AI Intelligence Index 50 vs 51, but 60% lower cost per task. Who wins by scenario.
QUICK INTEGRATION CODE SNIPPET
PYTHON 3.10+import os
from openai import OpenAI
# 100% OpenAI SDK compatible - just change the base_url
client = OpenAI(
api_key=os.environ.get("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 helpful coding assistant."},
{"role": "user", "content": "What is the best practice to integrate DeepSeek V4?"}
],
stream=True
)
for chunk in response:
print(chunk.choices[0].delta.content or "", end="")FREQUENTLY ASKED QUESTIONS
QUICK ANSWERSIs DeepSeek V4 Flash open source?
Yes. DeepSeek released the V4 Flash weights (284B total / 13B active, 1M context) under the MIT license on Hugging Face on July 31, 2026. You can download them for free or call them through the official API.
Download the weights →How much does DeepSeek V4 Flash cost?
The official API charges $0.14 per 1M input tokens and $0.28 per 1M output tokens, with a roughly 98% discount on context-cache hits ($0.0028 / 1M). That makes it dramatically cheaper than GPT-5.5 or Claude for most workloads.
Full pricing guide →Does DeepSeek V4 Flash support image input?
No — V4 Flash is text-only. For image support, community setups pair it with Xiaomi MiMo V2.5 in the vision slot, which bills at the same $0.14 / $0.28 per 1M rate.
Vision setup guide →What base URL do I use for the DeepSeek API?
Use https://api.deepseek.com. It is OpenAI-compatible (the /v1 prefix is optional), and DeepSeek also exposes an Anthropic-compatible endpoint at https://api.deepseek.com/anthropic for Claude Code and similar tools.
API setup guide →Can I run DeepSeek V4 Flash on my own hardware?
Yes, though it is heavy. The FP4/FP8 weights are about 160 GB, so you realistically need a multi-GPU setup (two RTX 3090s or better) or a large unified-memory machine. The official vLLM recipe is the recommended path.
VRAM & model size →Is this site run by DeepSeek?
No. DeepSeek V4 Guide is an independent, fan-made resource. We are not affiliated with or endorsed by DeepSeek. Always check status.deepseek.com and the official docs for production-critical information.
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