DeepSeek vs ChatGPT: Open Source vs Proprietary AI
Compare current DeepSeek V4 models with OpenAI GPT models. Is open-source AI catching up? Pricing, performance, and self-hosting options compared.
Last updated: May 2026
Pricing Comparison
| Model | Provider | Input $/1M | Output $/1M | Context | Max Output |
|---|---|---|---|---|---|
| DeepSeek V4 Flash | DeepSeek | $0.14 | $0.28 | 1M | 384K |
| GPT-5.5 | OpenAI | $5 | $30 | 1.05M | 128K |
| DeepSeek V4 Pro | DeepSeek | $0.435 | $0.87 | 1M | 384K |
| GPT-4o | OpenAI | $2.5 | $10 | 128K | 16K |
Detailed Comparison
DeepSeek V4 Flash
DeepSeek
$0.14 / $0.28
per 1M tokens
Strengths
- + Current default DeepSeek V4 model
- + Extremely low API pricing
- + 1M context with very large max output
Best For
Budget-focused projects, high-volume processing
Context Window
1M
Max Output
384K
GPT-5.5
OpenAI
$5 / $30
per 1M tokens
Strengths
- + OpenAI frontier model
- + Multi-modal capabilities
- + Most mature ecosystem
Best For
Enterprise production, multi-modal tasks
Context Window
1.05M
Max Output
128K
DeepSeek V4 Pro
DeepSeek
$0.435 / $0.87
per 1M tokens
Strengths
- + Current DeepSeek Pro family model
- + Official 1/4-of-original API pricing
- + Structured output support
Best For
Cost-sensitive production workloads
Context Window
1M
Max Output
384K
GPT-4o
OpenAI
$2.5 / $10
per 1M tokens
Strengths
- + Native multi-modal (text, vision, audio)
- + Real-time conversation support
- + Proven production reliability
Best For
Multi-modal applications, real-time interactions
Context Window
128K
Max Output
16K
Verdict
DeepSeek V4 models are dramatically cheaper in the canonical data and now list 1M context windows with very large max output. GPT models provide broader multi-modal capabilities and a more mature ecosystem. Choose DeepSeek for budget-conscious API workloads; choose OpenAI for enterprise reliability, ecosystem depth, and multi-modal features.
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FAQ
Which is cheaper, DeepSeek V4 Flash or GPT-5.5?
DeepSeek V4 Flash costs $0.14/$0.28 per million tokens (input/output), while GPT-5.5 costs $5/$30. DeepSeek V4 Flash is cheaper for input.
Which has a larger context window?
DeepSeek V4 Flash supports 1M context, while GPT-5.5 supports 1.05M. Larger context windows allow processing more text in a single request.
Which should I choose for my project?
DeepSeek V4 models are dramatically cheaper in the canonical data and now list 1M context windows with very large max output. GPT models provide broader multi-modal capabilities and a more mature ecosystem. Choose DeepSeek for budget-conscious API workloads; choose OpenAI for enterprise reliability, ecosystem depth, and multi-modal features.