The hottest API design Substack posts right now

And their main takeaways
Category
Top Technology Topics

iOS System Design interviews in 2026

Jacob’s Tech Tavern • 6122 implied HN points • 03 Mar 26
🕹 Technology API design
  1. Use a simple, reusable framework (scoping, functional and non‑functional requirements, data model, API design, high‑level design, drill‑downs) to structure every system design answer.
  2. Prioritize data flow and architecture over UI framework debates; fully understand and scope the problem before drawing or choosing implementation details.
  3. Practice with real worked examples and focused prep notes so you can confidently handle common iOS system design prompts and make your study time efficient.

The Mythical Non-Roboticist

General Robots • 199 HN points • 14 Mar 24
🕹 Technology API design
  1. Programming robots is inherently complex due to dealing with the real world and imperfect conditions.
  2. Design APIs and frameworks for users as smart as you are, but less tolerant of unnecessary complexity.
  3. Robotics development is challenging due to both intrinsic complexity and incidental 'stupid bullshit' complexity that must be navigated.

System Design: Feature Flag

The ZenMode • 42 implied HN points • 24 Jan 25
🕹 Technology API design
  1. Feature flags allow you to turn app features on or off without changing the code. This is like having a light switch for each feature, making it easy to manage them.
  2. Different types of feature flags help with various tasks, like rolling out incomplete features or testing new ideas with users. This way, you can learn what works best before a full launch.
  3. Building a feature flag system requires a control service, a way to store the flags, and an interface to access them in your app. This helps keep everything organized and responsive.

Consumer-focused API Design

The API Changelog • 1 implied HN point • 17 Jan 26
🕹 Technology API design
  1. Design APIs by engaging real users first and doing product discovery so you define problems, needs, and value before building anything.
  2. Use user stories that name the user, their location (tool/context), their goal, and the benefit; these details guide the right API style and workflows.
  3. Treat API capabilities as business-aligned features that deliver clear benefits and marketable value, and adopt a product-focused mindset instead of designing for engineering convenience.
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Non-technical API Design Should Be Possible

The API Changelog • 9 implied HN points • 15 Nov 24
🕹 Technology API design
  1. API design doesn't have to be technical. Non-technical people can focus on understanding what users need and planning the API without coding.
  2. Involving non-technical individuals early in API design can help identify user challenges and improve API functionality, making them more aligned with user needs.
  3. With the right tools, like Flotiq, non-technical people can create and test APIs easily, allowing for immediate feedback before handing off to developers for more complex tasks.

Documentation-driven API Design

The API Changelog • 6 implied HN points • 24 Jan 25
🕹 Technology API design
  1. You can create an API by simply writing down what you want it to do, and AI can help turn that into a working API document. It's as easy as writing a description and letting the technology handle the rest.
  2. Using AI tools like ChatGPT, you can get detailed how-to guides for your API based on a simple description, making it easier to understand how to use it.
  3. By generating an OpenAPI document from your description, you can quickly set up a mock API server, allowing you to test and get feedback on your API design in no time.

Lỗ hổng chuyển tiền hay là suy nghĩ như một hacker

Thái | Hacker | Kỹ sư tin tặc • 19 implied HN points • 04 Jan 20
🕹 Technology API design
  1. When designing an API for money transfers in a mobile banking system, it's crucial to consider user authentication and authorization to prevent fraudulent activities.
  2. In mobile apps, the challenge lies in implementing user authentication without standard mechanisms like HTTP cookies, requiring solutions like OAuth or JWT.
  3. Creating security solutions for mobile banking requires a blend of applied security and product security expertise, emphasizing the importance of identity access management beyond just finding vulnerabilities.

The Hard Things about Naming Things

The API Changelog • 3 implied HN points • 02 Feb 24
🕹 Technology API design
  1. Use familiarity when naming new operations to make it easy for developers to understand.
  2. Use identity to disambiguate names and make the purpose of the operation clear.
  3. Follow consistency in naming conventions across different operations in your organization to maintain clarity.

Selectively Serving Your API Reference

The API Changelog • 0 implied HN points • 07 Feb 25
🕹 Technology API design
  1. You can create an API reference that adapts to different users, offering both a human-friendly and machine-readable version. It's important to meet the needs of both audiences.
  2. Using an OpenAPI document makes it easy to generate a comprehensive API reference without much effort. It's like having a complete guide available for your API.
  3. Content negotiation allows you to serve the right version of your API reference based on the request type. This way, humans get a readable document, while machines receive the necessary JSON data.

HackerRank Springboot Test — Trades Api

Better Engineers • 0 implied HN points • 03 May 24
🕹 Technology API design
  1. You can create REST APIs for managing trade records using Spring Boot and JPA. Start by setting up the project and required dependencies.
  2. Understanding the API endpoints is crucial. You need to handle POST, GET, and provide some query parameters to filter trades.
  3. Don’t forget to design the database schema properly and create service and controller classes for handling requests and responses.

Yes, IO is possible in a functional world

Reflective Software Engineering • 0 implied HN points • 12 Nov 22
🕹 Technology API design
  1. Isolate IO side effects to maintain purity in domain logic, improving testability and readability.
  2. In functional programming, keep domain code side-effect free and contain side effects in the outer layers for simplicity and easy testing.
  3. Centralizing side effects through repositories can simplify code, improve maintainability, and make it easier to reason about.