DeepSeek V4 Flash vs GPT-5.5
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for DeepSeek V4 Flash and GPT-5.5.
DeepSeek V4 Flash
DeepSeek V4 Flash is an efficiency-optimized Mixture-of-Experts model from DeepSeek with 284B total parameters and 13B activated parameters, supporting a 1M-token context window. It is designed for fast inference and...
GPT-5.5
GPT-5.5 is OpenAI’s frontier model designed for complex professional workloads, building on GPT-5.4 with stronger reasoning, higher reliability, and improved token efficiency on hard tasks. It features a 1M+ token...
Technical Specifications
| Specification | DeepSeek V4 Flash | GPT-5.5 |
|---|---|---|
| Provider | DeepSeek | OpenAI |
| Context Window | 1,048,576 tokens | 1,050,000 tokens |
| Agent Suitability | 86/100 | 95/100 |
| Time to First Token (TTFT) | 120 ms | 380 ms |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2026-04-24 | 2026-04-24 |
API Pricing Comparison
Input Price per Million Tokens
DeepSeek V4 Flash
$0.09
GPT-5.5
$5.00
Output Price per Million Tokens
DeepSeek V4 Flash
$0.18
GPT-5.5
$30.00
Want to test both models live?
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
DeepSeek V4 Flash Quirks & Gotchas
- ▸Best cost-per-token ratio of any hosted API — ideal for high-throughput pipelines
- ▸Lower agentic performance vs V4 Pro — route complex tool calls accordingly
GPT-5.5 Quirks & Gotchas
- ▸Best for JSON schema adherence — strict mode available via response_format parameter
- ▸Requires explicit tool_choice for deterministic function calling