/poʊst/
n. “Send it, trust it, let it change the world.”
POST is an HTTP request method used to submit data to a server, typically causing a change in server state or triggering an action. Unlike GET, which only retrieves information, POST is intended for creating or updating resources. The client packages data in the request body, which the server interprets according to the endpoint’s rules.
For example, when submitting a form on https://catenco.de/contact, your browser sends a POST request containing fields like name, email, and message. The server then processes this data, perhaps storing it in a database, sending an email, or triggering another workflow.
POST requests are not idempotent, meaning repeating the same request can result in multiple side effects — like creating duplicate entries or sending multiple emails. This is why it is commonly paired with confirmation mechanisms, such as redirect-after-submit patterns, to prevent accidental repetition.
In web development, POST is central to RESTful APIs, form submissions, and any action where client input modifies server state. Tools like fetch in JavaScript, curl in the terminal, or libraries like Axios simplify creating POST requests with structured payloads such as JSON or URL-encoded forms.
Security considerations are critical when using POST. Since the data resides in the request body, it is not visible in URLs, unlike GET query strings. However, POST data still travels over the network and should always be encrypted using TLS to prevent interception. Input validation and server-side sanitization are necessary to avoid injection attacks or unintended consequences.
POST requests also support sending files, multipart form data, and complex objects, making them versatile for modern web applications. APIs often define POST endpoints for creating new resources, processing transactions, or interacting with services like SaaS platforms.
In summary, POST is the workhorse method for sending data, triggering actions, and enabling interactivity on the web. It complements GET and other HTTP methods, forming the foundation of request-response architecture that powers websites, apps, and APIs today.