# Together AI — DeepSeek-V4 Flash 0731 vs GPT-5.6 Luna on DeepSWE: Cost and Coding

- Company: Together AI (together.ai)
- Announced: 2026-08-06T00:00:00+00:00
- Subject: Inference platform
- Open weights: yes
- Models affected: DeepSeek-V4 Flash 0731, GPT-5.6 Luna
- License: Open weights
- Pricing: $0.10 per rollout
- Source: https://www.together.ai/blog/deepseek-v4-flash-0731-vs-gpt-5-6-luna-on-deepswe-cost-and-coding
- Record: https://forck.live/items/3651-deepseek-v4-flash-0731-vs-gpt-5-6-luna-on-deepswe-cost-and-coding

The post compares DeepSeek-V4 Flash 0731 and GPT-5.6 Luna on DeepSWE, showing that while GPT-5.6 Luna is more accurate, DeepSeek-V4 Flash is much cheaper, and a cascade strategy combining both outperforms Luna alone on accuracy and cost.

## Evidence

Verbatim from https://www.together.ai/blog/deepseek-v4-flash-0731-vs-gpt-5-6-luna-on-deepswe-cost-and-coding:

> While GPT-5.6 Luna is the stronger engineer on every quality measure, DeepSeek-V4 Flash 0731 is cheap enough that a DeepSeek-first cascade beats Luna alone on both accuracy and cost.

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