{
  "id": 101683,
  "title": "I used Spring Boot daily but never really understood what happened after pressing Enter in Postman.",
  "url": "https://urgent.news/2026/08/03/i-used-spring-boot-daily-but-never-really-understood-what-happened",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-08-03T21:08:25.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/curious_niloufer/i-used-spring-boot-daily-but-never-really-understood-what-happened-after-pressing-enter-in-postman-5cej"
  },
  "original_language": "en",
  "account": "Most individuals regularly utilize Spring Boot in their day-to-day tasks. They craft a @RestController, execute the application, and send a request via Postman, receiving a response. However, have you ever pondered what transpires between clicking Send in Postman and the controller method being invoked? Upon delving into Spring's internal workings, I discovered that multiple layers collaborate prior to my controller being called. Here is a high-level overview of request processing: Postman │ ▼ Operating System │ ▼ Embedded Tomcat │ ▼ Servlet Filter Chain │ ▼ Spring Security (JWT) │ ▼ DispatcherServlet │ ▼ Controller │ ▼ Service │ ▼ Repository │ ▼ Database The element that caught me off guard was my long-held belief that the request directly reaches my controller. In truth, the sequence unfolds as follows: Initially, the Operating System directs the request to the application operating on the designated port (for instance, 8080). The request then enters Embedded Tomcat. Subsequently, it traverses the Servlet Filter Chain. If security is enabled, Spring Security authenticates the JWT. Once validated, the request reaches Spring MVC's DispatcherServlet, which locates the appropriate controller. Thus, your controller processes the request only after several foundational components have already handled it. The essential takeaway is that comprehending this request journey diminishes the mystique surrounding Spring Boot. Rather than rote memorization of annotations, one gains insight into their functionality. In the forthcoming article, I will elucidate how Spring Boot automatically initiates Embedded Tomcat before the first request arrives.",
  "summary": "Most of us use Spring Boot every day. We create a @RestController, run the application, hit an endpoint from Postman, and get a response. But have you ever wondered what actually happens between clicking \"Send\" in Postman and your controller method executing? When I started digging into Spring internals, I realized there are several layers working together before my controller is even called.…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}