How do I know if my HLD or LLD is good?
Share it with a teammate before coding. If they ask questions, the doc is missing something. Fix the doc, not just answer the question. The test is: can a developer code from it without questions?
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More FAQs in How to Write a Good HLD and LLD Document
Start with the goal in one sentence. Use an architecture diagram. Label components, communication, and protocols. Keep it short. Skip the fluff about why popular tools are popular.
Use tables for schemas. Show API contracts with method, path, body, response, and status codes. Write logic as numbered steps. List error cases explicitly. Include edge cases. The goal is a developer can code from it without questions.
As short as possible while being clear. HLD often fits on one page with a diagram. LLD is longer because it covers every endpoint, but each section should be just the necessary detail.
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