OpenAI API Platform Guide: Models, APIs, and Agents
A systematic guide to the OpenAI API platform covering model selection, Chat Completions vs Responses API, tool calling, structured outputs, Assistants and Agents SDK, and pricing and cost control.
Google Gemini API Guide: Models, Multimodality, and SDK
A hands-on guide to the Google Gemini API covering Gemini 3 model selection, multimodal and long-context input, the google-genai SDK, the Interactions API, Google AI Studio vs Vertex AI, and pricing.
Anthropic Claude API Guide: Models, Tools, and Agents
A practical guide to the Claude API covering the Fable/Opus/Sonnet/Haiku model lineup, the Messages API, tool use, streaming, thinking, Claude Code, the Agent SDK, and per-token pricing.