DeepSeek V4 Flash vs Gemini 3.5
2026 - Pricing, benchmarks, and use case comparison
Quick take
- •DeepSeek V4 Flash is open-weights - free to self-host with no API costs. Gemini 3.5 requires paid API access.
- •Gemini 3.5 has a 1M context window - 8x larger than DeepSeek V4 Flash's 128K. Better for long documents and large codebases.
- •DeepSeek V4 Flash is open-source: fine-tune it, self-host it, or use any inference provider. Gemini 3.5 is closed-source.
Specs comparison
| DeepSeek V4 Flash | Gemini 3.5 | |
|---|---|---|
| Provider | DeepSeek | Google DeepMind |
| Type | Open source | Closed source |
| Context window | 128K | ✓1M |
| Input / 1M tokens | ✓Free (self-host) | TBA |
| Output / 1M tokens | Free (self-host) | TBA |
| Release date | 2025-12 | 2026-05 |
Strengths
DeepSeek V4 Flash
- ✓Lower latency than full DeepSeek V4
- ✓Sparser MoE activation - cleaner residual stream representations
- ✓Effective for LLM steering and interpretability research
- ✓Open-source weights
- ✓Strong performance-to-cost ratio
Gemini 3.5
- ✓Action-first architecture for agentic and multi-step workflows
- ✓1M token context window - largest in class
- ✓Powers Google Antigravity CLI for terminal-native coding
- ✓Native Workspace integration with autonomous task execution
- ✓Companion Gemini Omni handles anything-to-anything multimodal generation
Which should you choose?
Choose DeepSeek V4 Flash if you need...
- →Latency-sensitive inference pipelines
- →LLM interpretability and steering research
- →Self-hosted low-latency deployments
- →Cost-sensitive production applications
Choose Gemini 3.5 if you need...
- →Agentic workflows requiring multi-step tool use
- →Large codebase comprehension and editing
- →Google Workspace automation
- →Long document and multimodal analysis