DeepSeek V4.1 Flash vs Union Alpha (Stealth)
A direct, empirical evaluation of DeepSeek V4.1 Flash (DeepSeek-AI) against Union Alpha (Stealth) (OpenRouter & OpenCode).
DeepSeek V4.1 Flash
Developed by DeepSeek-AI · 552B parameters
High-throughput software engineering, autonomous coding loops, terminal agents, 1M long-context retrieval, and low-cost production inference.
Union Alpha (Stealth)
Developed by OpenRouter & OpenCode · Multi-Model Ensemble Mixture parameters
Terminal coding agents, pull-request synthesis, multi-model consensus verification, and zero-cost autonomous refactoring.
| Metric | DeepSeek V4.1 Flash | Union Alpha (Stealth) |
|---|---|---|
| SWE-bench Verified | 67.2% | 74.2% |
| MMLU-Pro | 78.4% | 89.8% |
| MATH-500 | 92.6% | 95.4% |
| Context Window | 1,000,000 tokens | 256,000 tokens |
| Input Pricing (per 1M) | $0.06 | $0.00 |
| Output Pricing (per 1M) | $0.22 | $0.00 |