deepseek-v3.1-terminus

deepseek-v3.1-terminus is a efficient-tier language model from DeepSeek with 671B parameters. deepseek-v3.1-terminus is an open-weights model, meaning the weights are publicly available for self-hosting, fine-tuning, and deployment on your own infrastructure — not just through DeepSeek's API. DeepSeek is a Chinese AI lab's open-weights model family, known for competitive performance at very low API prices — particularly strong on coding and math benchmarks.

deepseek-v3.1-terminus is priced at $0.27/1M input tokens and $1/1M output tokens. Output tokens are 3.7× more expensive than input tokens — this ratio reflects the sequential nature of autoregressive generation, which requires a separate forward pass per output token versus parallel processing of all input tokens simultaneously. At a typical usage pattern of 1,000 input tokens and 500 output tokens per call, deepseek-v3.1-terminus costs approximately $0.77 per 1,000 API calls. DeepSeek does not publish a prompt caching rate for this model, so repeated long contexts are billed at the standard $0.27/1M input rate.

Its 164K-token context window handles most long-document tasks — roughly 75,000 words or a full novel — without requiring chunking or retrieval augmentation. Median latency (P50 time-to-first-token) is approximately 460ms — suitable for interactive applications where sub-second response is acceptable. Throughput is approximately 135 tokens/second — adequate for streaming at comfortable reading speed. Maximum output length is 16K tokens — sufficient for long-form content generation, detailed code files, and extended reports.

deepseek-v3.1-terminus is best suited to coding, chat, cost. Supported capabilities include function calling / tool use for agentic workflows, streaming token output for real-time UIs. Function calling support makes it suitable for building AI agents, structured data extraction pipelines, and any workflow requiring the model to invoke external APIs or return typed JSON. When evaluating this model for a specific workload, the most important factors are: context window (does your input fit?), output price (how long are your generations?), and latency (is this interactive or batch?). The pricing table above shows how deepseek-v3.1-terminus compares to similar models across these dimensions.

deepseek-v3.1-terminus sits in the efficient tier — optimized for speed and cost while maintaining solid quality, ideal for high-volume or latency-sensitive workloads. As an open-weights model, deepseek-v3.1-terminus can be self-hosted on GPU compute (see the GPU rental comparison on this site) to eliminate per-token API costs entirely — the break-even point versus API pricing depends on your volume and the GPU hourly rate. When comparing deepseek-v3.1-terminus to alternatives, use the similar models section on this page to find models at comparable price points with different capability tradeoffs. The intelligence score (83/100) reflects aggregate benchmark performance — a useful proxy for general capability, though real-world performance varies significantly by task type. Always test with your specific prompts and use case before committing to a model for production.