When you compare raw generation costs, DeepSeek’s deepseek‑v4‑flash charges $0.1336 per 1M output tokens while OpenAI’s gpt‑5‑nano asks $0.4 per 1M output tokens. That difference alone can swing the economics of any high‑volume content engine.
### Input pricing and cache discounts
Both models charge a modest fee for feeding prompts. OpenAI lists gpt‑5‑nano at $0.05 per 1M input tokens and a cached‑input rate of $0.005 per 1M tokens. DeepSeek’s deepseek‑v4‑flash costs $0.0668 per 1M input tokens with a cached‑input price of $0.0134 per 1M tokens. The cached‑input discount from OpenAI is deeper, meaning repeated system prompts shrink faster under OpenAI’s plan.
### Generation cost decides the winner
The bulk of the budget for most applications sits in output tokens. DeepSeek’s $0.1336 per 1M output tokens is more than three times cheaper than OpenAI’s $0.4 per 1M output tokens. For workloads that generate long responses—summarization pipelines, automated article creation, or large‑scale chat bots—the DeepSeek rate delivers a clear advantage. OpenAI’s pricing remains competitive for balanced workloads where input and output volumes are similar.
| Vendor | Model | Input | Cached input | Output |
|---|---|---|---|---|
| OpenAI | gpt‑5‑nano | $0.05 per 1M tokens | $0.005 per 1M tokens | $0.4 per 1M tokens |
| DeepSeek | deepseek‑v4‑flash | $0.0668 per 1M tokens | $0.0134 per 1M tokens | $0.1336 per 1M tokens |
The table makes the trade‑off transparent. OpenAI offers a tighter input price and a stronger cache discount, which helps read‑heavy pipelines that reuse prompts extensively. DeepSeek flips the advantage on the output side, making it the obvious pick for write‑heavy scenarios. Both vendors bill strictly on token consumption, so there are no hidden seat fees or annual commitments.
If your product leans on rapid prototyping, frequent prompt reuse, and modest generation, gpt‑5‑nano provides the most economical mix of input and cache pricing. If you run high‑throughput generation—automated newsletters, bulk code scaffolding, or data‑driven report synthesis—deepseek‑v4‑flash will shave significant dollars off the bottom line. Pricing verified on 2026-09-12.