DeepSeek V4 Pro vs Gemini 3.5 Flash
DeepSeek V4 Pro (2026) and Gemini 3.5 Flash (2026) are frontier-tier reasoning models from DeepSeek and Google DeepMind. DeepSeek V4 Pro ships a 1M-token context window, while Gemini 3.5 Flash ships a 1M-token context window. On pricing, DeepSeek V4 Pro costs $0.43/1M input tokens versus $1.5/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
DeepSeek V4 Pro is ~245% cheaper at $0.43/1M; pay for Gemini 3.5 Flash only for coding workflow support.
Decision scorecard
Local evidence first| Signal | DeepSeek V4 Pro | Gemini 3.5 Flash |
|---|---|---|
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1M | 1M |
| Cheapest output | $0.87/1M tokens | $9/1M tokens |
| Provider routes | 3 tracked | 2 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- DeepSeek V4 Pro has the lower cheapest tracked output price at $0.87/1M tokens.
- DeepSeek V4 Pro has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags DeepSeek V4 Pro for Coding, RAG, and Agents.
- Gemini 3.5 Flash has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Gemini 3.5 Flash uniquely exposes Vision, Multimodal, and Code execution in local model data.
- Local decision data tags Gemini 3.5 Flash for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output prices on this page.
DeepSeek V4 Pro
$566
Cheapest tracked route: DeepSeek Platform
Gemini 3.5 Flash
$3,450
Cheapest tracked route: Google AI Studio
Estimated monthly gap: $2,885. Batch, cache, and negotiated pricing are excluded from this local estimate.
Switch friction
- No overlapping tracked provider route is sourced for DeepSeek V4 Pro and Gemini 3.5 Flash; plan for SDK, billing, or endpoint changes.
- Gemini 3.5 Flash is $8.13/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Gemini 3.5 Flash adds Vision, Multimodal, and Code execution in local capability data.
- No overlapping tracked provider route is sourced for Gemini 3.5 Flash and DeepSeek V4 Pro; plan for SDK, billing, or endpoint changes.
- DeepSeek V4 Pro is $8.13/1M 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.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-24 | 2026-05-19 |
| Context window | 1M | 1M |
| Parameters | 1.6T | — |
| Architecture | mixture of experts | decoder only |
| License | MIT | Proprietary |
| Knowledge cutoff | - | 2025-01 |
Pricing and availability
| Pricing attribute | DeepSeek V4 Pro | Gemini 3.5 Flash |
|---|---|---|
| Input price | $0.43/1M tokens | $1.5/1M tokens |
| Output price | $0.87/1M tokens | $9/1M tokens |
| Providers |
Capabilities
| Capability | DeepSeek V4 Pro | Gemini 3.5 Flash |
|---|---|---|
| Vision | No | Yes |
| Multimodal | No | Yes |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | No | Yes |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on vision: Gemini 3.5 Flash, multimodal input: Gemini 3.5 Flash, and code execution: Gemini 3.5 Flash. 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.
For cost, DeepSeek V4 Pro lists $0.43/1M input and $0.87/1M output tokens, while Gemini 3.5 Flash lists $1.5/1M input and $9/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts DeepSeek V4 Pro lower by about $3.18 per million blended tokens. Availability is 3 providers versus 2, so concentration risk also matters.
Choose DeepSeek V4 Pro when provider fit, lower input-token cost, and broader provider choice are central to the workload. Choose Gemini 3.5 Flash when coding workflow support and larger context windows are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions.
FAQ
Which has a larger context window, DeepSeek V4 Pro or Gemini 3.5 Flash?
Gemini 3.5 Flash supports 1M tokens, while DeepSeek V4 Pro 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 Pro or Gemini 3.5 Flash?
DeepSeek V4 Pro is cheaper on tracked token pricing. DeepSeek V4 Pro costs $0.43/1M input and $0.87/1M output tokens. Gemini 3.5 Flash costs $1.5/1M input and $9/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is DeepSeek V4 Pro or Gemini 3.5 Flash open source?
DeepSeek V4 Pro is listed under MIT. Gemini 3.5 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 V4 Pro or Gemini 3.5 Flash?
Gemini 3.5 Flash 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 Pro or Gemini 3.5 Flash?
Gemini 3.5 Flash 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 Pro and Gemini 3.5 Flash?
DeepSeek V4 Pro is available on DeepSeek Platform, Fireworks AI, and OpenRouter. Gemini 3.5 Flash is available on Google AI Studio and GCP Vertex AI. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-05-19. Data sourced from public model cards and provider documentation.