DeepSeek V4 Flash vs GPT-5.4 mini
Which one to choose
Pick DeepSeek V4 Flash for text-only agent loops and long documents where you want open weights and switchable thinking; pick GPT-5.4 mini when inputs include images or screenshots, or when you need computer use and MCP. V4 Flash reasons close to V4 Pro, while GPT-5.4 mini is made to run as a fast subagent.
Pricing comparison
| DeepSeek V4 Flash | GPT-5.4 mini | |
|---|---|---|
| Model maker | DeepSeek | OpenAI |
| Delivery availability | Available | Available |
| Context window | 1M | 400K |
| Max output | 384K | 128K |
| Official price | Input$0.15per 1M tokensOutput$0.60per 1M tokens | Input$0.75per 1M tokensOutput$4.50per 1M tokens |
| TokenLab price | — | Input$0.525per 1M tokensOutput$3.15per 1M tokens |
| Model performance |
|
|
| Capabilities | JSON modePrompt CacheTool use | Prompt CacheTool useVision |
Choose DeepSeek V4 Flash when
- Your inputs are text only and you want thinking switched on per request at low, high or max effort.
- You run long tool-using agent loops and want prompt caching and JSON output on a small model.
- You want the open weights of the model family available if you also self-host.
Choose GPT-5.4 mini when
- Your inputs include screenshots, diagrams or other images.
- You build subagents that a larger model orchestrates in parallel.
- You need computer use or MCP support.
How they differ
| Aspect | DeepSeek V4 Flash | GPT-5.4 mini |
|---|---|---|
| Model design | Open-weight mixture-of-experts model, the smaller V4 model, tuned for speed and low serving cost. | OpenAI's small model carrying much of GPT-5.4's behavior, for coding and subagents. |
| Input types | Text only; images need deepseek-v4.1-flash. | Text and image input. |
| Thinking | Thinking and non-thinking modes, with the reasoning text returned separately and passed back on tool turns. | Reasoning effort from none to xhigh, defaulting to none. |
| Structured output | Supports response schemas for JSON that must match a structure. | No response-schema enforcement; validate JSON in your own code. |
| Agent tooling | Tool calls and prompt caching for long agent loops. | Computer use and MCP support for agents that operate software. |
Summary
- DeepSeek V4 Flash: Input $0.15 / Output $0.60 per 1M tokens; GPT-5.4 mini: Input $0.525 / Output $3.15 per 1M tokens. Rates depend on the billing unit, specification, and usage. Compare matching conditions in the model's detailed pricing; a single rate does not determine the total cost.
- DeepSeek V4 Flash has a 2.5x larger context window
- DeepSeek V4 Flash supports 3.0x more output tokens
FAQ
DeepSeek V4 Flash or GPT-5.4 mini for coding agents?
For text-only coding agents, V4 Flash is a good fit, with thinking you can switch on when a step needs it. If the agent must look at screenshots or use a computer, GPT-5.4 mini is the one that accepts images and supports computer use.
Can V4 Flash read images?
No. DeepSeek V4 Flash accepts text only, so screenshots and diagrams cannot go in. DeepSeek V4.1 Flash is the DeepSeek option that reads images with text, while GPT-5.4 mini already accepts images.
Is it easy to move from GPT-5.4 mini to V4 Flash?
Text prompts move easily. Agent code needs care: in thinking mode V4 Flash returns reasoning text separately, and it must be passed back on later tool turns. Check any image or computer-use steps, which V4 Flash cannot do.
Can I use them together?
Yes. Use V4 Flash for text-heavy steps and GPT-5.4 mini for steps that need images or computer use, then compare combined results against using one model for everything.
Which is cheaper, DeepSeek V4 Flash or GPT-5.4 mini?
DeepSeek V4 Flash: Input $0.15 / Output $0.60 per 1M tokens; GPT-5.4 mini: Input $0.525 / Output $3.15 per 1M tokens. Rates depend on the billing unit, specification, and usage. Compare matching conditions in the model's detailed pricing; a single rate does not determine the total cost.
What are the key differences between DeepSeek V4 Flash and GPT-5.4 mini?
DeepSeek V4 Flash: JSON mode. GPT-5.4 mini: Vision
Sources
Reviewed Oct 2, 2026