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REST API

API REST

A REST API is a web interface that exposes resources through URLs and manipulates them with HTTP's standard verbs: GET to read, POST to create, PUT to update, DELETE to remove. REST (Representational State Transfer) is the architectural style that made web APIs simple, predictable and universal: nearly every online service exposes one.

Definition

How it works

The key principles: every resource has a unique address (say /users/42), operations use HTTP methods with their semantics, responses typically arrive as JSON with standard status codes (200 OK, 404 not found, 429 too many requests), and every request is stateless, that is self-sufficient: the server remembers nothing between calls, which makes the system scalable and reliable.

Applications

In AI, REST APIs are the door to the models: OpenAI's chat completions, Anthropic's messages and Hugging Face endpoints are REST APIs accepting prompts as JSON and returning generations. Anyone integrating AI into products almost always goes through here. Beyond AI, payments, maps, weather and social platforms expose their functions via REST.

History & etymology

REST was defined by Roy Fielding, co-author of the HTTP specification, in his 2000 doctoral dissertation at the University of California, Irvine: an after-the-fact systematization of the principles that had made the web scalable. The name describes the mechanism: transferring representations of resource state. During the 2000s REST displaced the more complex SOAP to become the lingua franca of web integration.

How it's used in Grace

Grace's professional scenarios on AI integration put real requests in front of you: designing calls to model REST APIs, handling error codes, structuring JSON payloads. The skills requested on the AI Jobs board constantly mention familiarity with these interfaces.

Related terms

• API
• API Gateway
• Webhook
• JSON Mode
• Rate Limiting

More in Fondamenti AI

• LLM (Large Language Model)
• Token
• Context Window
• Temperature
• AI Hallucination
• Fine-tuning
• RAG (Retrieval Augmented Generation)
• Embedding

Put it into practice

• Real scenario: apply this concept with an instant AI verdict.
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