Frequently Asked Questions
How to use the Claude API?
Use the Anthropic Messages API by sending a POST request to api.anthropic.com/v1/messages with your API key, model name, and messages array. ClaudKit lets you build requests visually and generates ready-to-use code in curl, Python, and JavaScript.
What is the Anthropic API?
The Anthropic API provides programmatic access to Claude AI models. It uses a messages-based format with system prompts, user messages, and assistant responses. Authentication is via API key with the x-api-key header.
How much does the Claude API cost?
Claude API pricing per 1M tokens: Haiku costs $0.25 input / $1.25 output, Sonnet costs $3.00 / $15.00, and Opus costs $15.00 / $75.00. Use our built-in pricing estimator to calculate costs for your specific use case and see monthly projections.
What models are available in the Claude API?
Anthropic offers Claude Haiku (fastest, cheapest), Claude Sonnet (balanced performance), and Claude Opus (most capable). All share the same API format with different speed, quality, and cost tradeoffs.
How do I get a Claude API key?
Sign up at console.anthropic.com, navigate to API Keys, and create a new key. Keys start with "sk-ant-api03-". Store it securely and never expose it in client-side code.
Is ClaudKit free to use?
Yes, ClaudKit is completely free. Build API requests visually, copy generated code, and estimate costs without signing up. You only pay Anthropic for actual API usage when you test with your own key.