DeepSeek V3.1 vs Gemini 2.5 Flash
DeepSeek V3.1 (2026) and Gemini 2.5 Flash (2025) are compact production models from DeepSeek and Google DeepMind. DeepSeek V3.1 ships a 64K-token context window, while Gemini 2.5 Flash ships a 1M-token context window. On MMLU PRO, DeepSeek V3.1 leads by 2.4 pts. On pricing, Gemini 2.5 Flash costs $0.15/1M input tokens versus $0.56/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Gemini 2.5 Flash is ~273% cheaper at $0.15/1M; pay for DeepSeek V3.1 only for coding workflow support.
Specs
| Released | 2026-03-01 | 2025-06-17 |
| Context window | 64K | 1M |
| Parameters | — | — |
| Architecture | mixture of experts | decoder only |
| License | Open Source | Proprietary |
| Knowledge cutoff | - | 2025-01 |
Pricing and availability
| DeepSeek V3.1 | Gemini 2.5 Flash | |
|---|---|---|
| Input price | $0.56/1M tokens | $0.15/1M tokens |
| Output price | $1.68/1M tokens | $0.6/1M tokens |
| Providers |
Capabilities
| DeepSeek V3.1 | Gemini 2.5 Flash | |
|---|---|---|
| Vision | ||
| Multimodal | ||
| Reasoning | ||
| Function calling | ||
| Tool use | ||
| Structured outputs | ||
| Code execution |
Benchmarks
| Benchmark | DeepSeek V3.1 | Gemini 2.5 Flash |
|---|---|---|
| MMLU PRO | 83.3 | 80.9 |
Deep dive
On shared benchmark coverage, MMLU PRO has DeepSeek V3.1 at 83.3 and Gemini 2.5 Flash at 80.9, with DeepSeek V3.1 ahead by 2.4 points. The largest visible gap is 2.4 points on MMLU PRO, 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 function calling: Gemini 2.5 Flash and tool use: Gemini 2.5 Flash. Both models share vision, multimodal input, structured outputs, and code execution, 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.
For cost, DeepSeek V3.1 lists $0.56/1M input and $1.68/1M output tokens, while Gemini 2.5 Flash lists $0.15/1M input and $0.6/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Gemini 2.5 Flash lower by about $0.61 per million blended tokens. Availability is 6 providers versus 4, so concentration risk also matters.
Choose DeepSeek V3.1 when coding workflow support and broader provider choice are central to the workload. Choose Gemini 2.5 Flash when coding workflow support, larger context windows, and lower input-token cost are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, DeepSeek V3.1 or Gemini 2.5 Flash?
Gemini 2.5 Flash supports 1M tokens, while DeepSeek V3.1 supports 64K tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, DeepSeek V3.1 or Gemini 2.5 Flash?
Gemini 2.5 Flash is cheaper on tracked token pricing. DeepSeek V3.1 costs $0.56/1M input and $1.68/1M output tokens. Gemini 2.5 Flash costs $0.15/1M input and $0.6/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is DeepSeek V3.1 or Gemini 2.5 Flash open source?
DeepSeek V3.1 is listed under Open Source. Gemini 2.5 Flash 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 vision, DeepSeek V3.1 or Gemini 2.5 Flash?
Both DeepSeek V3.1 and Gemini 2.5 Flash expose vision. 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 multimodal input, DeepSeek V3.1 or Gemini 2.5 Flash?
Both DeepSeek V3.1 and Gemini 2.5 Flash expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Where can I run DeepSeek V3.1 and Gemini 2.5 Flash?
DeepSeek V3.1 is available on Microsoft Foundry, Fireworks AI, NVIDIA NIM, Together AI, and AWS Bedrock. Gemini 2.5 Flash is available on Google AI Studio, GCP Vertex AI, Replicate 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.