OpenAI vs DeepSeek

GPT-5 mini vs DeepSeek V4 Flash

Compare GPT-5 mini and DeepSeek V4 Flash across pricing, context window, capabilities, benchmarks, and API access to choose the better fit for reasoning-heavy tasks versus long-context workloads.

GPT-5 mini
Aug 07, 2025 400,000 context 128,000 tokens output

Overview Comparison

Structured side-by-side differences for the highest-signal model metadata.

GPT-5 mini
DeepSeek V4 Flash

Provider

The entity that currently provides this model.

GPT-5 mini OpenAI
DeepSeek V4 Flash DeepSeek

Model ID

The routed model identifier exposed by upstream providers.

GPT-5 mini openai/gpt-5-mini
DeepSeek V4 Flash deepseek/deepseek-v4-flash:free

Input Context Window

The number of tokens supported by the input context window.

GPT-5 mini 400,000 tokens
DeepSeek V4 Flash 1.0M tokens

Maximum Output Tokens

The number of tokens that can be generated by the model in a single request.

GPT-5 mini 128,000 tokens tokens
DeepSeek V4 Flash 384,000 tokens tokens

Open Source

Whether the model's code is available for public use.

GPT-5 mini No
DeepSeek V4 Flash Yes

Release Date

When the model was first released.

GPT-5 mini Aug 07, 2025
DeepSeek V4 Flash Apr 24, 2026

Knowledge Cut-off Date

When the model's knowledge was last updated.

GPT-5 mini 2024-05-31
DeepSeek V4 Flash Unknown

API Providers

The providers that currently expose the model through an API.

GPT-5 mini
OpenRouter
DeepSeek V4 Flash
OpenRouter

Modalities

Types of data each model can process or return.

GPT-5 mini
Text Image File
DeepSeek V4 Flash
Text

Pricing Comparison

Compare current token pricing before you choose the cheaper or more scalable API option.

GPT-5 mini OpenAI
Input price $0.25 Per 1M tokens
Output price $2.00 Per 1M tokens
DeepSeek V4 Flash DeepSeek
Input price $0.14 Per 1M tokens
Output price $0.00 Per 1M tokens

Capabilities Comparison

See where each model overlaps, where they differ, and which one supports more of the features you care about.

Capability
GPT-5 mini
DeepSeek V4 Flash
Fast Inference Optimized for lower latency compared to full GPT-5, making it suitable for applications where response speed is a priority.
GPT-5 mini Supported
DeepSeek V4 Flash
File
GPT-5 mini Supported
DeepSeek V4 Flash
Image
GPT-5 mini Supported
DeepSeek V4 Flash
Large Context Window Processes up to 400,000 tokens in a single context, enabling long documents, extended conversations, or large codebases to be handled in one request.
GPT-5 mini Supported
DeepSeek V4 Flash
MCP Server Support Accepts MCP (Model Context Protocol) server configurations as inputs, enabling standardized integration with external context and data sources.
GPT-5 mini Supported
DeepSeek V4 Flash
Reasoning
GPT-5 mini Supported
DeepSeek V4 Flash Supported
Structured Output
GPT-5 mini Supported
DeepSeek V4 Flash Supported
Text
GPT-5 mini Supported
DeepSeek V4 Flash Supported
Text Generation Generates natural language text across a wide range of formats including summaries, instructions, and structured responses.
GPT-5 mini Supported
DeepSeek V4 Flash
Tool Use Supports function calling and tool integrations, allowing the model to invoke external tools or APIs as part of a response.
GPT-5 mini Supported
DeepSeek V4 Flash
Tools
GPT-5 mini Supported
DeepSeek V4 Flash Supported

Benchmark Comparison

Shared benchmark rows make it easier to compare performance where both models have published scores.

Benchmark GPT-5 mini DeepSeek V4 Flash
GPQA Diamond
PhD-level science questions (biology, physics, chemistry)
GPT-5 mini 82.8%
DeepSeek V4 Flash N/A
HLE
Questions that challenge frontier models across many domains
GPT-5 mini 19.7%
DeepSeek V4 Flash N/A
LiveCodeBench
Real-world coding tasks from recent competitions
GPT-5 mini 83.8%
DeepSeek V4 Flash N/A
MMLU-Pro
Expert knowledge across 14 academic disciplines
GPT-5 mini 83.7%
DeepSeek V4 Flash N/A
SciCode
Scientific research coding and numerical methods
GPT-5 mini 39.2%
DeepSeek V4 Flash N/A
Community discussion

What Reddit discussions say about GPT-5 mini vs DeepSeek V4 Flash

GPT-5 mini and DeepSeek V4 Flash are both surfacing live Reddit discussions, giving this comparison a community layer beyond specs and benchmarks.

The most visible threads right now are clustered in r/GithubCopilot, r/opencodeCLI, r/LocalLLaMA.

DeepSeek V4 Flash r/LocalLLaMA 281 upvotes 147 comments May 10, 2026
I have DeepSeek V4 Pro at home

Just wanted to share that I used u/LegacyRemaster slightly modified (Q4\_K\_M conversion support) DeepSeek V4 [CUDA repo](https://github.com/Fringe210/llama.cpp-deepseek-v4-flash-cuda) (based on u/antirez [work](https://github.com/antirez/llama.cpp-deepseek-v4-flash)) to convert and run Q4\_K\_M [DeepSeek V4 Pro](https://huggingface.co/deepseek-ai/DeepSeek-V4-Pro) on my Epyc workstation (Genoa 9374F, 12 x 96GB RAM, single RTX PRO 6000 Max-Q) and it worked right from the start:

(base) phm@epyc:~/projects/llama.cpp-deepseek-v4-flash-cuda/build-cuda$ ./bin/llama-cli -m ../models/DeepSeek-V4-Pro-Q4_K_M.gguf --no-repack -ub 128 --chat-template-file ../models/templates/deepseek-ai-DeepSeek-V3.2.jinja
ggml_cuda_init: found 1 CUDA devices (Total VRAM: 97247 MiB):
Device 0: NVIDIA RTX PRO 6000 Blackwell Max-Q Workstation Edition, compute capability 12.0, VMM: yes, VRAM: 97247 MiB

Loading model...

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build : b8936-44c7b01de
model : DeepSeek-V4-Pro-Q4_K_M.gguf
modalities : text

available commands:
/exit or Ctrl+C stop or exit
/regen regenerate the last response
/clear clear the chat history
/read <file> add a text file
/glob <pattern> add text files using globbing pattern

> who are you?

[Start thinking]
Okay, the user is asking "who are you?" This is a simple, introductory question. I need to introduce myself clearly and warmly. I should state my name, creator, and key features that are most relevant to a new user. I can mention that I'm free, my context window, knowledge cutoff, file support, and availability on web and app. I'll end with an open invitation for further questions to keep the conversation going.
[End thinking]

Hi there! I'm DeepSeek, an AI assistant created by the Chinese company DeepSeek (深度求索). I'm here to help you with questions, creative tasks, problem-solving, and pretty much anything you're curious about!

Here's a bit about me:
- **Free to use** - no charges for chatting with me
- **1M context window** - I can handle huge amounts of text at once (like entire book trilogies!)
- **Knowledge cutoff: May 2025** - I'm reasonably up-to-date
- **File upload support** - I can read text from images, PDFs, Word docs, Excel files, and more
- **Web search capability** - though you need to manually enable it via the search button
- **Available on web and mobile app** - with voice input support on the app

I'm a pure text-based model, so I can't "see" images directly, but I can read any text in uploaded files. I aim to be warm, helpful, and detailed in my responses.

What can I help you with today? 😊

[ Prompt: 12.2 t/s | Generation: 8.6 t/s ]

> /exit

Exiting...
common_memory_breakdown_print: | memory breakdown [MiB] | total free self model context compute unaccounted |
common_memory_breakdown_print: | - CUDA0 (RTX PRO 6000 Blackwell Max-Q Workstation Edition) | 97247 = 4022 + ( 92472 = 87766 + 84 + 4621) + 753 |
common_memory_breakdown_print: | - Host | 793994 = 793954 + 0 + 39 |
~llama_context: CUDA_Host compute buffer size of 39.1719 MiB, does not match expectation of 15.3535 MiB

The model file is 859GB.

Update: ran some lineage-bench prompts to see if the model has healthy brain and no problems so far.

Open Reddit thread
GPT-5 mini r/OpenAI 219 upvotes 68 comments August 11, 2025
GPT-5 Benchmarks: How GPT-5, Mini, and Nano Perform in Real Tasks

Hi everyone,

We ran task benchmarks on the GPT-5 series models, and as per general consensus, they are likely not a break through in intelligence. But they are a good replacement of o3, o1 and gpt-4.1. And lower latency and the cost improvements are impressive! Likely really good models for chatgpt, even though users have to get used to them.

**For builders, perhaps one way to look at it:**

o3 and gpt-4.1 -> gpt-5

o1 -> gpt-5-mini

o1-mini -> gpt-5-nano

**But let's look at a tricky failure case to be aware of.**

Part of our context oriented task evals, we task the model to read a travel journal and count the number of visited cities:

Question: "How many cities does the author mention"

Expected: 19

GPT-5: 12

Models that consistently gets this right is gemini-2.5-flash, gemini-2.5-pro, claude-sonnet-4, claude-opus-4, claude-sonnet-3.7, claude-3.5-sonnet, gpt-oss-120b, grok-4.

To be a good model for building with, context attention is one of the primary criterias. What makes Anthropic models stand out is how well they have been utilising the context window even since sonnet-3.5. Gemini series and Grok seems to be putting attention to this as well.

You can read more about our task categories and eval methods here: [https://opper.ai/models](https://opper.ai/models)

For those building with it, anyone else seeing similar strengths/weaknesses?

Open Reddit thread
GPT-5 mini r/LocalLLaMA 152 upvotes 40 comments March 15, 2026
Qwen3.5-27B performs almost on par with 397B and GPT-5 mini in the Game Agent Coding League

Hi LocalLlama.

Here are the results from the March run of the GACL. A few observations from my side:

* **GPT-5.4** clearly leads among the major models at the moment.
* **Qwen3.5-27B** performed better than every other Qwen model except **397B**, trailing it by only **0.04 points**. In my opinion, it’s an outstanding model.
* **Kimi2.5** is currently the top **open-weight** model, ranking **#6 globally**, while **GLM-5** comes next at **#7 globally**.
* Significant difference between Opus and Sonnet, more than I expected.
* **GPT models dominate the Battleship game.** However, **Tic-Tac-Toe** didn’t work well as a benchmark since nearly all models performed similarly. I’m planning to replace it with another game next month. Suggestions are welcome.

For context, **GACL** is a league where models generate **agent code** to play **seven different games**. Each model produces **two agents**, and each agent competes against every other agent except its paired “friendly” agent from the same model. In other words, the models themselves don’t play the games but they generate the agents that do. Only the top-performing agent from each model is considered when creating the leaderboards.

All **game logs, scoreboards, and generated agent codes** are available on the league page.

[Github Link](https://github.com/summersonnn/Game-Agent-Coding-Benchmark)

[League Link](https://gameagentcodingleague.com/leaderboard.html)

Open Reddit thread
View more discussions →

Which model should you choose?

Use the summary below to decide which model better fits your workflow, budget, and feature requirements.

Best fit for

GPT-5 mini

GPT-5 mini is a stronger fit for reasoning-heavy tasks, tool-augmented workflows, multimodal applications.

Best fit for

DeepSeek V4 Flash

DeepSeek V4 Flash is a stronger fit for long-context workloads, reasoning-heavy tasks, tool-augmented workflows.

Verdict

Choose GPT-5 mini if you prioritize reasoning-heavy tasks, tool-augmented workflows, multimodal applications. Choose DeepSeek V4 Flash if your workflow depends more on long-context workloads, reasoning-heavy tasks, tool-augmented workflows.

FAQ

Common questions about GPT-5 mini vs DeepSeek V4 Flash

What is the main difference between GPT-5 mini and DeepSeek V4 Flash?

GPT-5 mini leans toward reasoning-heavy tasks, tool-augmented workflows, multimodal applications, while DeepSeek V4 Flash is better suited to long-context workloads, reasoning-heavy tasks, tool-augmented workflows.

Which model is cheaper: GPT-5 mini or DeepSeek V4 Flash?

DeepSeek V4 Flash starts lower on input pricing at $0.1400 per 1M input tokens, compared with $0.2500 for GPT-5 mini.

Which model has the larger context window: GPT-5 mini or DeepSeek V4 Flash?

GPT-5 mini is listed with a context window of 400,000, while DeepSeek V4 Flash is listed with 1.0M.

How should I evaluate GPT-5 mini vs DeepSeek V4 Flash for my use case?

This comparison currently includes 5 shared benchmark rows, helping you compare practical performance across overlapping evaluations.