HTTP

HTTP (Hypertext Transfer Protocol) is the foundation of traffic on the World Wide Web, and by most estimates the large majority of that traffic is now API calls rather than browser page loads. HTTP defines the rules for transferring representations — text, JSON, images, video, and more — between clients and servers, and it is the substrate that REST, webhooks, and nearly every modern API convention are built upon.

• Stateless - Each request is independent, which keeps the protocol simple but pushes state into cookies, tokens, and headers when it is needed.
• Human-readable semantics - Methods, status codes, and headers are easy to read and reason about, which is a large part of why the web scaled.
• Extensible - Headers carry metadata that enables caching, authentication, and content negotiation without changing the core protocol.
• Secure option (HTTPS) - Modern deployments encrypt traffic with TLS, making secure transport the default expectation for any API.
• Universal compatibility - Supported by effectively every client, server, and device, which is why it remains the lowest common denominator for integration.

When it comes to API governance, HTTP is the place to focus for standardization — consistent methods, status codes, headers, and media types are where a little discipline pays off across the whole enterprise. The versions that layer on top, HTTP/2 and HTTP/3, keep these same semantics while improving transport, and newer specifications like HTTP Message Signatures extend HTTP with the integrity and authenticity guarantees that agent-driven API consumption increasingly demands.