Compare · updated 2026-11-01
GPT-5.5 vs DeepSeek Flash
GPT-5.5 is better at quick answers, writing, coding, maths, structured data, long documents, translation; DeepSeek Flash is better at reasoning. DeepSeek Flash is the cheaper of the two on output.
Measured quality by task
| Task | GPT-5.5 | DeepSeek Flash | Better |
|---|---|---|---|
| Quick answers | 93/100 | 91/100 | GPT-5.5 |
| Writing | 94/100 | 87/100 | GPT-5.5 |
| Coding | 91/100 | 85/100 | GPT-5.5 |
| Reasoning | 79/100 | 80/100 | DeepSeek Flash |
| Maths | 82/100 | 78/100 | GPT-5.5 |
| Structured data | 96/100 | 92/100 | GPT-5.5 |
| Long documents | 93/100 | 91/100 | GPT-5.5 |
| Translation | 92/100 | 90/100 | GPT-5.5 |
Quality is Nivana’s measured score for each kind of task, from weekly pairwise evals judged by models from several labs. Prices are live AI Gateway list prices per million tokens. Updated 2026-11-01. How this is measured.
Price and context
| GPT-5.5 | DeepSeek Flash | |
|---|---|---|
| Lab | OpenAI | DeepSeek |
| Input per 1M tokens | $5 | $0.3 |
| Output per 1M tokens | $30 | $1.2 |
| Typical chat answer | $0.029 | $0.00129 |
| Context window | 1M | 1.05M |
| Router picks it for | Fallback only | Fallback only |
Which should you use?
Use the one that wins the kind of work you do most, unless the price gap outweighs the quality gap for easy requests. Or don’t choose: Nivana scores both, and the rest of the pool, on every request and sends it to whichever is best for that request.
Questions
Is GPT-5.5 better than DeepSeek Flash?
On Nivana’s weekly evals GPT-5.5 scores higher on 7 of 8 task types (quick answers, writing, coding, maths, structured data, long documents, translation) and DeepSeek Flash on 1 (reasoning). Neither is better at everything.
Which is better for coding, GPT-5.5 or DeepSeek Flash?
GPT-5.5: 91/100 against 85/100 for DeepSeek Flash on Nivana’s coding evals.
Which is better for writing, GPT-5.5 or DeepSeek Flash?
GPT-5.5: 94/100 against 87/100 for DeepSeek Flash on Nivana’s writing evals.
Which is cheaper, GPT-5.5 or DeepSeek Flash?
DeepSeek Flash: $1.2 per million output tokens against $30 for GPT-5.5, about 25.0× less. A typical chat answer costs about $0.0013 on DeepSeek Flash and $0.029 on GPT-5.5.
Or let the router pick, per request
Nivana sends every message to the model that scores best for it, sets how hard it thinks, and tells you which one answered. 2,000 free credits to start, no card.