DeepSeek V4 Pro vs GPT-5.5

DeepSeek V4 Pro and GPT-5.5 are both current production-tier models. DeepSeek V4 Pro is meaningfully cheaper at $0.43 / $0.87 per 1M. GPT-5.5 leads on coding, general knowledge, instruction following.

Specs side by side

Metric
DeepSeek
DeepSeek V4 Pro
OpenAI
GPT-5.5
Input price (per 1M)$0.435$5
Output price (per 1M)$0.87$30
Context window1M tokens1.1M tokens
Speed tierbalancedbalanced
Open weightsYesNo
EU regionNoYes
Free tierNoNo
Prompt cachingYesYes
Vision inputNoYes
Extended thinkingYesYes

When to choose each

DeepSeek

Choose DeepSeek V4 Pro if…

  • Cost is a priority ($0.43 / $0.87 per 1M vs $5 / $30 per 1M)
  • You need open weights for self-hosting or fine-tuning
OpenAI

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
  • General knowledge is central to your workload

Benchmark delta

DeepSeek V4 Pro leads on

DeepSeek V4 Pro has no meaningful benchmark lead in this pair.

GPT-5.5 leads on

  • Coding
  • General knowledge
  • Instruction following
  • Multilingual
  • Tool use

FAQ — DeepSeek V4 Pro vs GPT-5.5

DeepSeek V4 Pro vs GPT-5.5 — which is better?

DeepSeek V4 Pro and GPT-5.5 are both current production-tier models. DeepSeek V4 Pro is meaningfully cheaper at $0.43 / $0.87 per 1M. GPT-5.5 leads on coding, general knowledge, instruction following. The right pick depends on your use case — see "When to choose each" above for a data-driven decision.

How does DeepSeek V4 Pro pricing compare to GPT-5.5?

DeepSeek V4 Pro costs $0.43 / $0.87 per 1M vs GPT-5.5 at $5 / $30 per 1M. DeepSeek V4 Pro is cheaper on output tokens by roughly 3348%. Both support prompt caching, which reduces effective cost by 80-90% on repeat system prompts.

Does DeepSeek V4 Pro 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 Pro. Enough for entire codebases, books, or multi-document RAG.

Is there a free tier for DeepSeek V4 Pro or GPT-5.5?

DeepSeek V4 Pro: no — No free tier on the official API — but at $0.435/$0.87 per 1M it is near-free vs frontier peers. GPT-5.5: no — Paid-only — no free API tier; available via ChatGPT Plus/Pro.

Which is better for coding — DeepSeek V4 Pro or GPT-5.5?

GPT-5.5 leads on coding benchmarks (DeepSeek V4 Pro: 91/100, GPT-5.5: 95/100). For production coding agents also weigh tool-use performance — DeepSeek V4 Pro scores 86, GPT-5.5 scores 94.