Learn CRYSTAL with Real Code Examples

CLI tool parsing arguments

REST API backend

Concurrent web crawler

JSON data processor

Simple microservice with fiber-based concurrency

Check type mismatches reported by compiler

Verify Shards dependencies

Use `--error-trace` for detailed compilation errors

Ensure correct Crystal version

Debug runtime exceptions with logging

Use built-in `Spec` module

Write unit tests in `spec/` directory

Run `crystal spec`

Test concurrency edge cases

Use mocks and fixtures for IO testing

Deploy compiled binaries directly

Containerized deployment (Docker)

Serverless functions with native binary

Package CLI tools for distribution

Cloud deployment for web backends

Crystal compiler

Shards dependency manager

Kemal web framework

Amber web framework

crystal tool for testing & formatting

HTTP servers and REST APIs

Database libraries (PostgreSQL, SQLite, MySQL)

JSON/XML processing

CLI tools integration

Interfacing with C libraries via `lib`

Leverage Shards for library management

Use macros for repeated code patterns

Write tests in parallel with development

Use fiber concurrency for efficient IO

Keep code clean and Ruby-like for readability

Build CLI argument parser

Create small REST API

Implement concurrent task runner

Write JSON processor

Develop microservice with fibers