DeepSeek V4 Flash vs GPT-5.5
DeepSeek V4 Flash and GPT-5.5 are both current production-tier models. DeepSeek V4 Flash is meaningfully cheaper at $0.14 / $0.28 per 1M. GPT-5.5 leads on coding, reasoning, general knowledge.
Specs side by side
| Metric | DeepSeek DeepSeek V4 Flash | OpenAI GPT-5.5 |
|---|---|---|
| Input price (per 1M) | $0.14 | $5 |
| Output price (per 1M) | $0.28 | $30 |
| Context window | 1M tokens | 1.1M tokens |
| Speed tier | balanced | balanced |
| Open weights | Yes | No |
| EU region | No | Yes |
| Free tier | OpenRouter | No |
| Prompt caching | Yes | Yes |
| Vision input | No | Yes |
| Extended thinking | Yes | Yes |
When to choose each
Choose DeepSeek V4 Flash if…
- Cost is a priority ($0.14 / $0.28 per 1M vs $5 / $30 per 1M)
- You need open weights for self-hosting or fine-tuning
- You want a free tier for prototyping
Choose GPT-5.5 if…
- EU data residency is required
- HIPAA eligibility is required
- You need image input / vision
- You need realtime speech-to-speech
- Coding is central to your workload
- Reasoning is central to your workload
Benchmark delta
DeepSeek V4 Flash leads on
DeepSeek V4 Flash has no meaningful benchmark lead in this pair.
GPT-5.5 leads on
- Coding
- Reasoning
- General knowledge
- Instruction following
- Multilingual
- Tool use
FAQ — DeepSeek V4 Flash vs GPT-5.5
DeepSeek V4 Flash vs GPT-5.5 — which is better?
DeepSeek V4 Flash and GPT-5.5 are both current production-tier models. DeepSeek V4 Flash is meaningfully cheaper at $0.14 / $0.28 per 1M. GPT-5.5 leads on coding, reasoning, general knowledge. The right pick depends on your use case — see "When to choose each" above for a data-driven decision.
How does DeepSeek V4 Flash pricing compare to GPT-5.5?
DeepSeek V4 Flash costs $0.14 / $0.28 per 1M vs GPT-5.5 at $5 / $30 per 1M. DeepSeek V4 Flash is cheaper on output tokens by roughly 10614%. Both support prompt caching, which reduces effective cost by 80-90% on repeat system prompts.
Does DeepSeek V4 Flash or GPT-5.5 have the bigger context window?
GPT-5.5 has a 1.1M-token context window — 1× the 1M context of DeepSeek V4 Flash. Enough for entire codebases, books, or multi-document RAG.
Is there a free tier for DeepSeek V4 Flash or GPT-5.5?
DeepSeek V4 Flash: yes — Often available free via OpenRouter; official API is extremely cheap ($0.14 cache miss, $0.0028 cached input). GPT-5.5: no — Paid-only — no free API tier; available via ChatGPT Plus/Pro.
Which is better for coding — DeepSeek V4 Flash or GPT-5.5?
GPT-5.5 leads on coding benchmarks (DeepSeek V4 Flash: 89/100, GPT-5.5: 95/100). For production coding agents also weigh tool-use performance — DeepSeek V4 Flash scores 84, GPT-5.5 scores 94.