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People reach for DeepSeek for one reason: near-top-tier quality on code and reasoning, but noticeably cheaper than the rest. The family has two models — the flagship deepseek-v4-pro and the fast, low-cost deepseek-v4-flash. Both are text-only, have a long context window, and speak the OpenAI-compatible protocol. This page covers when DeepSeek pays off, what it does well, and what it can’t do.

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Why DeepSeek is the budget pick

The main argument is price-to-quality. DeepSeek delivers results close to top-tier models on code and logic, but its tokens cost far less. If you run high request volumes, long documents, or a CI pipeline where every cent counts, DeepSeek usually cuts the bill to a fraction of what it was, with no meaningful quality loss.
  • Per-token price — among the lowest of any strong model; deepseek-v4-flash is cheaper still than the flagship.
  • Quality — reasoning and code stay close to the top tier, not “economy class.”
  • Volume — the long context lets you avoid chopping documents into tiny pieces.
For exact per-token prices, see the Pricing page at www.ruapi.ai.

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Pro vs Flash — which one

Not sure? Start with Flash — it’s fast, costs next to nothing, and covers most work. Move up to Pro where you need the best result: hard code, precise reasoning, reliable tool use.

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Where DeepSeek is strong: code and reasoning

These are the two areas the family is built around.
  • Code — Pro confidently writes, completes, and refactors code, explains errors, and suggests fixes. A good fit for autocomplete, review, and test generation.
  • Reasoning — the model works through hard problems step by step: math, logic, requirement analysis, agent action planning.
  • Long context — large files and documents fit in the window whole, no chunking.
  • Function calling — Pro returns structured tool calls; see function calling for a ready example.
For long answers it’s handy to stream the response token by token instead of waiting for the full generation.

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What DeepSeek can’t do

DeepSeek models are text-only. You can’t pass images as input — there’s no vision: neither deepseek-v4-pro nor deepseek-v4-flash reads images, diagrams, or screenshots. If you need to interpret pictures, use a vision model — Claude, Gemini, or GLM-5V. The same key and the same base_url work across all families, so you can mix them: DeepSeek for text and code, a vision model for images.

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Connecting DeepSeek

DeepSeek speaks the OpenAI-compatible protocol — no separate library needed. Take any OpenAI SDK, change the base_url to https://www.ruapi.ai/v1, and put the model ID you want in the model field:
Step-by-step setup, the key, and a first request in Python and curl are in the Quickstart. Exact model IDs and prices are on the Pricing page at www.ruapi.ai.

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Next

Connect and first request

base_url, key, Python and curl code.

Claude models

Same key — top-tier quality and vision.

GLM models

Another strong value line, with a vision option (GLM-5V).