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Beginner-friendly guides on LLMs, agents, RAG and Spring AI, plus system design for your next interview. Clear steps, real code, no fluff.

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17AI Playbooks 9Spring AI 9System Design

@RestController
class AskController {
  private final ChatClient chat;

  AskController(ChatClient.Builder b) {
    this.chat = b.build();
  }

  @GetMapping("/ask")
  String ask(@RequestParam String q) {
    return chat.prompt().user(q)
               .call().content();
  }
}

Today's playbook Nov 11 Function Calling for Beginners: The Playbook on Letting AI Use Your Tools Start reading

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AI PlaybooksLLMs, agents, evals and guardrails explained from zero. 17 guides → Spring AIBuild RAG apps, MCP servers and agents in Java. 9 guides → System DesignInterview-ready designs with clear trade-offs. 9 guides → ProjectsEnd-to-end builds you can add to your portfolio. 4 guides →

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Why CodeSpy

Guides written by working engineers

01

Real systems, not toy examples

Every architecture is one you could actually ship, with the trade-offs left in.

02

Clear steps for beginners

Plain words, small steps and a "you are done when" check, so nobody gets lost.

03

Code you can actually run

Spring Boot, Python, Redis, Docker. Snippets are tested, not decorative.

Who's behind this

Two engineers, writing what we wish we'd had

Prashant Pandey

Founder & Editor-in-Chief

Leads editorial strategy, Spring AI and distributed-systems content. Obsessed with explaining hard things simply.

Spring AIDistributed systemsAI Playbooks

LinkedIn profile of Prashant Pandey

Ashmita Basu

Co-founder & Content Creator

Leads system design coverage, turning whiteboard-scale problems into guides anyone can follow.

System DesignInterviews

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