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11 pages in this section.
Explore the Claude API request lifecycle, from base URL and auth headers to the Messages API, to debug and optimize your API calls.
Learn Claude API fundamentals with 9 Python examples. Send messages, specify models and tokens, and parse responses.
Authenticate Claude API calls using the x-api-key header. Learn to configure API keys for the Python SDK and raw HTTP requests.
Install and configure the Anthropic Python SDK to call the Claude API. Learn to install the package, initialize a client, and make your first API call.
Look up Claude API request parameters like model, max_tokens, temperature, top_p, and top_k. Learn their types, defaults, and when to adjust them.
Compare Claude Fable 5, Opus 4.8, Sonnet 5, and Haiku 4.5 models to select the best option for your application's cost, latency, and quality needs.
Learn 25 best practices for reliable authentication, requests, and error handling when building on the Claude API with the Python SDK.
A single-page roundup of every highlight bullet from the 10 pages in the API Fundamentals section, grouped by source page so you can scan all 59 takeaways without opening each article individually.