DeepSeek V4 Flash vs Gemini 3.1 Pro Preview
DeepSeek V4 Flash (2026) and Gemini 3.1 Pro Preview (2026) are frontier reasoning models from DeepSeek and Google DeepMind. DeepSeek V4 Flash ships a 1m-token context window, while Gemini 3.1 Pro Preview ships a 1m-token context window. On SWE-bench Verified, Gemini 3.1 Pro Preview leads by 1.6 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
DeepSeek V4 Flash is safer overall; choose Gemini 3.1 Pro Preview when coding workflow support matters.
Decision scorecard
Local evidence first| Signal | DeepSeek V4 Flash | Gemini 3.1 Pro Preview |
|---|---|---|
| Best for | reasoning-heavy apps, tool-calling agents, and long-context analysis | multimodal apps, tool-calling agents, and long-context analysis |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1m | 1m |
| Cheapest output | $0.20/1M tokens | $12/1M tokens |
| Provider routes | 6 tracked | 5 tracked |
| Shared benchmarks | 3 rows | SWE-bench Verified leader |
Decision tradeoffs
- DeepSeek V4 Flash has the lower cheapest tracked output price at $0.20/1M tokens.
- DeepSeek V4 Flash has broader tracked provider coverage for fallback and procurement flexibility.
- DeepSeek V4 Flash uniquely exposes Reasoning in local model data.
- Local decision data tags DeepSeek V4 Flash for Coding, RAG, and Agents.
- Gemini 3.1 Pro Preview leads the largest shared benchmark signal on SWE-bench Verified by 1.6 points.
- Gemini 3.1 Pro Preview uniquely exposes Vision, Multimodal, and Code execution in local model data.
- Local decision data tags Gemini 3.1 Pro Preview for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
DeepSeek V4 Flash
$128
Cheapest tracked route/tier: OpenRouter
Gemini 3.1 Pro Preview
$4,600
Cheapest tracked route/tier: Google AI Studio
Estimated monthly gap: $4,472. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
- Gemini 3.1 Pro Preview is $11.80/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Reasoning before moving production traffic.
- Gemini 3.1 Pro Preview adds Vision, Multimodal, and Code execution in local capability data.
- Provider overlap exists on OpenRouter, Vercel AI Gateway, and OpenRouter; start route-level A/B tests there.
- DeepSeek V4 Flash is $11.80/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Code execution before moving production traffic.
- DeepSeek V4 Flash adds Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-24 | 2026-02-19 |
| Context window | 1m | 1m |
| Parameters | 284B | — |
| Architecture | mixture of experts | decoder only |
| License | MIT | Proprietary |
| Knowledge cutoff | - | 2025-01 |
Pricing and availability
| Pricing attribute | DeepSeek V4 Flash | Gemini 3.1 Pro Preview |
|---|---|---|
| Input price | $0.10/1M tokens |
|
| Output price | $0.20/1M tokens |
|
| Providers |
Capabilities
| Capability | DeepSeek V4 Flash | Gemini 3.1 Pro Preview |
|---|---|---|
| Vision | No | Yes |
| Multimodal | No | Yes |
| Reasoning | Yes | No |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | No | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | DeepSeek V4 Flash | Gemini 3.1 Pro Preview |
|---|---|---|
| SWE-bench Verified | 79.0 | 80.6 |
| Google-Proof Q&A | 88.1 | 94.3 |
| SWE-bench Pro | 52.6 | 54.2 |
Deep dive
On shared benchmark coverage, SWE-bench Verified has DeepSeek V4 Flash at 79 and Gemini 3.1 Pro Preview at 80.6, with Gemini 3.1 Pro Preview ahead by 1.6 points; Google-Proof Q&A has DeepSeek V4 Flash at 88.1 and Gemini 3.1 Pro Preview at 94.3, with Gemini 3.1 Pro Preview ahead by 6.2 points; SWE-bench Pro has DeepSeek V4 Flash at 52.6 and Gemini 3.1 Pro Preview at 54.2, with Gemini 3.1 Pro Preview ahead by 1.6 points. The largest visible gap is 6.2 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 vision: Gemini 3.1 Pro Preview, multimodal input: Gemini 3.1 Pro Preview, reasoning mode: DeepSeek V4 Flash, and code execution: Gemini 3.1 Pro Preview. Both models share 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.
For cost, DeepSeek V4 Flash lists $0.10/1M input and $0.20/1M output tokens on the cheapest tracked provider, while Gemini 3.1 Pro Preview lists tiered pricing: 0-200,001t is $2/1M input and $12/1M output; 200,001t+ is $4/1M input and $18/1M output. A 70/30 input-output blend puts DeepSeek V4 Flash lower by about $4.87 per million blended tokens. For tiered rows, this cheapest-track view can understate interactive or fast-lane spend, so compare the tier you will actually use. Availability is 6 providers versus 5, so concentration risk also matters.
Choose DeepSeek V4 Flash when reasoning depth, lower input-token cost, and broader provider choice are central to the workload. Choose Gemini 3.1 Pro Preview when coding workflow support 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 V4 Flash or Gemini 3.1 Pro Preview?
DeepSeek V4 Flash supports 1m tokens, while Gemini 3.1 Pro Preview supports 1m 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 V4 Flash or Gemini 3.1 Pro Preview?
DeepSeek V4 Flash lists $0.10/1M input and $0.20/1M output tokens on the cheapest tracked provider. Gemini 3.1 Pro Preview lists tiered pricing: 0-200,001t is $2/1M input and $12/1M output; 200,001t+ is $4/1M input and $18/1M output. Compare the tier you will actually use; cheap async pricing can overstate savings for interactive workflows. Provider discounts or batch pricing can still change the final bill.
Is DeepSeek V4 Flash or Gemini 3.1 Pro Preview open source?
DeepSeek V4 Flash is listed under MIT. Gemini 3.1 Pro Preview 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 V4 Flash or Gemini 3.1 Pro Preview?
Gemini 3.1 Pro Preview has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for multimodal input, DeepSeek V4 Flash or Gemini 3.1 Pro Preview?
Gemini 3.1 Pro Preview 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.
Where can I run DeepSeek V4 Flash and Gemini 3.1 Pro Preview?
DeepSeek V4 Flash is available on DeepSeek Platform, OpenRouter, Microsoft Foundry, Vercel AI Gateway, and Novita AI. Gemini 3.1 Pro Preview is available on Google AI Studio, GCP Vertex AI, OpenRouter, Replicate API, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-06-01. Data sourced from public model cards and provider documentation.