Notes from 5+ years in software engineering

Luis's Engineering Field Notes

Commands, patterns, mistakes, and lessons I keep coming back to while building web, mobile, backend, and cloud software.

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Start with an outcome

Follow a focused path or learn from a complete project.

Ship a production application

Move from idea to an observable, recoverable release.

Grow toward senior engineering

Develop ownership, judgment, communication, and system-level impact.

Build stronger backend systems

Connect API design, data, security, integrations, and reliability.

Prepare for engineering interviews

Practice technical explanation, system design, debugging, and evidence-based stories.

Technical notes

The references and examples I want close by when I'm building.

43 topics

HTML

Markup for the web

CSS

Style your pages

Sass

Programming | css

JavaScript

A quick reference for JavaScript concepts, functions, methods, and more.

JSON

Human-readable config & data format

Git

Version control for code

Homebrew

Package management for macOS and Linux

Node.js

Run JavaScript outside the browser

PHP

Server-side scripting for the web

Python

Readable, versatile programming language

React

Build interfaces from reusable components

TypeScript

Typed superset of JavaScript

Next.js

The React framework for production

SQL

Query and manage relational data

React Native

Build native mobile apps with React

AWS

Core cloud services and production patterns

Laravel

Productive PHP web application framework

Tailwind CSS

Utility-first styling for fast UI development

GraphQL

Typed APIs with client-selected data

REST APIs

Design and consume predictable HTTP APIs

Cypress

Reliable browser and end-to-end testing

Bash

Shell commands and dependable automation

Angular

Full-featured TypeScript application framework

Vue

Progressive framework for web interfaces

Kotlin

Modern programming for Android and the JVM

Swift

Safe, expressive development for Apple platforms

Java

Object-oriented programming on the JVM

C

Systems programming fundamentals and memory safety

Bootstrap

Responsive components and layout utilities

tRPC

End-to-end typesafe TypeScript APIs

GitHub Actions

Automate tests, builds, and deployments

WebSockets

Persistent, real-time two-way communication

Authentication

Sessions, tokens, authorization, and account safety

Webhooks

Receive external events safely and reliably

Stripe

Payments, subscriptions, and safe integrations

Firebase

Managed auth, data, messaging, and analytics

API Security

Protect APIs from common attacks and misuse

Pagination

Efficiently navigate large and changing datasets

Push Notifications

Reliable mobile and web notification delivery

Docker

Package and run applications consistently

Astro

Content-focused web framework with server-first islands

Supabase

Postgres, Auth, Storage, Realtime, and Edge Functions

Cloudflare

Edge compute, delivery, storage, and security platform

Featured case study

Making a patient-facing app feel faster

How measurement-led frontend refactoring improved a critical experience without a risky rewrite.

Read the case study

Project blueprints

Build complete applications with milestones, failure modes, and proof.

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Projects and work

Connect the field notes to real engineering practice and my portfolio.

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About these notes

The things I've learned—and the things I'm still learning

I'm Luis Colon, a software engineer working across web, mobile, backend systems, and cloud infrastructure. DevMarks is where I organize the references I repeatedly need, lessons from production work, and advice I wish I had earlier.

These are working field notes—not universal rules. They combine my professional experience, personal projects, official documentation, and ongoing research.

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