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OpenAI’s GPT is the model to reach for when you don’t yet know exactly what you need. Broad capability across tasks, the largest tooling ecosystem, and predictable function calling make it a safe first choice for most projects. Three versions are available through RuAPI, differing mainly in the balance of “smarter versus faster and cheaper.” Below is how to choose between them — and when another line is the more honest pick.

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The three GPT models

Not sure? Take gpt-5.4 — it covers almost everything. Step up to gpt-5.5 when you hit a quality ceiling on hard tasks, and down to gpt-5.4-mini when speed and cost matter more than peak intelligence.
Exact model IDs and per-token prices are on the Pricing page at www.ruapi.ai. New versions appear in the catalog automatically.

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Versatile and well-supported

The main reason to reach for GPT isn’t a peak score in one narrow area — it’s that it handles almost any task with equal confidence: code, analysis, chat, extraction, summarization. You never have to remember “what this model is good at.”
  • Ecosystem — GPT is the most common backend, so nearly every library, framework and no-code tool is written against it. Whatever you integrate, the GPT path is usually the best-trodden one.
  • OpenAI-compatible protocol — RuAPI serves the models in that same format, so any OpenAI SDK works. Only base_url changes.
  • Reliable function calling — GPT consistently returns structured tool calls, the basis for agents (see function calling for an example).
  • Vision — you can pass images as input: screenshots, diagrams, scans (see image input).
For long answers you can stream the response token by token instead of waiting for the full reply.

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When to pick GPT (and when another line)

GPT is a strong default. Here’s the honest picture of where it stops being the best pick:
  • Pick GPT when you want an all-rounder, maximum tool compatibility, or you simply don’t want to guess — gpt-5.4 covers most scenarios.
  • Claude is often more careful in long agentic chains and across large codebases.
  • Gemini wins on very long context and multimodal tasks with heavy input.
  • DeepSeek is attractive when cost at scale drives the decision and hard reasoning isn’t critical.
One key covers all lines. You can switch freely between GPT, Claude, Gemini and DeepSeek within a single project — only the model value changes.

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Connecting GPT

GPT speaks the OpenAI-compatible protocol, so any OpenAI SDK or a tool like Cursor, Cline or n8n works. You only need to point base_url at RuAPI:
Step by step, with the key and curl, in the Quickstart. You top up in USDT and no VPN is needed; a Visa / Mastercard also works — see Top up.

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Next

Connect and first request

base_url, key, Python and curl code.

Claude models

Same key — when agent precision matters more.

Gemini models

Very long context and multimodality.