DeepSeek V4 Pro vs GPT-5.5
DeepSeek V4 Pro (2026) and GPT-5.5 (2026) are frontier-tier reasoning models from DeepSeek and OpenAI. DeepSeek V4 Pro ships a 1M-token context window, while GPT-5.5 ships a 1.05M-token context window. On MMLU PRO, GPT-5.5 leads by a hair. On pricing, DeepSeek V4 Pro costs $1.74/1M input tokens versus $5/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
DeepSeek V4 Pro is ~187% cheaper at $1.74/1M; pay for GPT-5.5 only for coding workflow support.
Specs
| Released | 2026-04-24 | 2026-04-23 |
| Context window | 1M | 1.05M |
| Parameters | 1.6T | — |
| Architecture | mixture of experts | decoder only |
| License | MIT | Proprietary |
| Knowledge cutoff | - | 2025-12 |
Pricing and availability
| DeepSeek V4 Pro | GPT-5.5 | |
|---|---|---|
| Input price | $1.74/1M tokens | $5/1M tokens |
| Output price | $3.48/1M tokens | $30/1M tokens |
| Providers |
Capabilities
| DeepSeek V4 Pro | GPT-5.5 | |
|---|---|---|
| Vision | ||
| Multimodal | ||
| Reasoning | ||
| Function calling | ||
| Tool use | ||
| Structured outputs | ||
| Code execution |
Benchmarks
| Benchmark | DeepSeek V4 Pro | GPT-5.5 |
|---|---|---|
| MMLU PRO | 87.5 | 88.1 |
| SWE-bench Verified | 80.6 | 88.7 |
| Google-Proof Q&A | 90.1 | 93.6 |
| Chatbot Arena | 1460.0 | 1488.0 |
Deep dive
On shared benchmark coverage, MMLU PRO has DeepSeek V4 Pro at 87.5 and GPT-5.5 at 88.1, with GPT-5.5 ahead by 0.6 points; SWE-bench Verified has DeepSeek V4 Pro at 80.6 and GPT-5.5 at 88.7, with GPT-5.5 ahead by 8.1 points; Google-Proof Q&A has DeepSeek V4 Pro at 90.1 and GPT-5.5 at 93.6, with GPT-5.5 ahead by 3.5 points. The largest visible gap is 8.1 points on SWE-bench Verified, 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: GPT-5.5, multimodal input: GPT-5.5, and code execution: GPT-5.5. 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 $1.74/1M input and $3.48/1M output tokens, while GPT-5.5 lists $5/1M input and $30/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts DeepSeek V4 Pro lower by about $10.24 per million blended tokens. Availability is 1 providers versus 1, so concentration risk also matters.
Choose DeepSeek V4 Pro when provider fit and lower input-token cost are central to the workload. Choose GPT-5.5 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.
FAQ
Which has a larger context window, DeepSeek V4 Pro or GPT-5.5?
GPT-5.5 supports 1.05M 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 GPT-5.5?
DeepSeek V4 Pro is cheaper on tracked token pricing. DeepSeek V4 Pro costs $1.74/1M input and $3.48/1M output tokens. GPT-5.5 costs $5/1M input and $30/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is DeepSeek V4 Pro or GPT-5.5 open source?
DeepSeek V4 Pro is listed under MIT. GPT-5.5 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 GPT-5.5?
GPT-5.5 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. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, DeepSeek V4 Pro or GPT-5.5?
GPT-5.5 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 GPT-5.5?
DeepSeek V4 Pro is available on DeepSeek Platform. GPT-5.5 is available on OpenAI API. Provider coverage can affect latency, region availability, compliance posture, and fallback options. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Continue comparing
Last reviewed: 2026-04-29. Data sourced from public model cards and provider documentation.