DeepSeek V4 Flash vs GPT-5.4
DeepSeek V4 Flash (2026) and GPT-5.4 (2026) are frontier-tier reasoning models from DeepSeek and OpenAI. DeepSeek V4 Flash ships a 1M-token context window, while GPT-5.4 ships a not-yet-sourced context window. On MMLU PRO, GPT-5.4 leads by 1.3 pts. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing.
DeepSeek V4 Flash is safer overall; choose GPT-5.4 when coding workflow support matters.
Specs
| Released | 2026-04-24 | 2026-03-05 |
| Context window | 1M | — |
| Parameters | 284B | — |
| Architecture | mixture of experts | decoder only |
| License | MIT | Proprietary |
| Knowledge cutoff | - | 2025-08 |
Pricing and availability
| DeepSeek V4 Flash | GPT-5.4 | |
|---|---|---|
| Input price | - | $2.5/1M tokens |
| Output price | - | $15/1M tokens |
| Providers | - |
Capabilities
| DeepSeek V4 Flash | GPT-5.4 | |
|---|---|---|
| Vision | ||
| Multimodal | ||
| Reasoning | ||
| Function calling | ||
| Tool use | ||
| Structured outputs | ||
| Code execution |
Benchmarks
| Benchmark | DeepSeek V4 Flash | GPT-5.4 |
|---|---|---|
| MMLU PRO | 86.2 | 87.5 |
| Google-Proof Q&A | 88.1 | 92.0 |
Deep dive
On shared benchmark coverage, MMLU PRO has DeepSeek V4 Flash at 86.2 and GPT-5.4 at 87.5, with GPT-5.4 ahead by 1.3 points; Google-Proof Q&A has DeepSeek V4 Flash at 88.1 and GPT-5.4 at 92, with GPT-5.4 ahead by 3.9 points. The largest visible gap is 3.9 points on Google-Proof Q&A, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on multimodal input: GPT-5.4 and code execution: GPT-5.4. Both models share reasoning mode, function calling, tool use, and structured outputs, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
Pricing coverage is uneven: DeepSeek V4 Flash has no token price sourced yet and GPT-5.4 has $2.5/1M input tokens. Provider availability is 0 tracked routes versus 2. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose DeepSeek V4 Flash when provider fit are central to the workload. Choose GPT-5.4 when coding workflow support and broader provider choice are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Is DeepSeek V4 Flash or GPT-5.4 open source?
DeepSeek V4 Flash is listed under MIT. GPT-5.4 is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for multimodal input, DeepSeek V4 Flash or GPT-5.4?
GPT-5.4 has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for reasoning mode, DeepSeek V4 Flash or GPT-5.4?
Both DeepSeek V4 Flash and GPT-5.4 expose reasoning mode. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for function calling, DeepSeek V4 Flash or GPT-5.4?
Both DeepSeek V4 Flash and GPT-5.4 expose function calling. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for tool use, DeepSeek V4 Flash or GPT-5.4?
Both DeepSeek V4 Flash and GPT-5.4 expose tool use. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Where can I run DeepSeek V4 Flash and GPT-5.4?
DeepSeek V4 Flash is available on the tracked providers still being sourced. GPT-5.4 is available on OpenAI API and OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-04-24. Data sourced from public model cards and provider documentation.