Technical Tools

Binary (base 2):

• 0 and 1, the native language of computers
• Each position = power of 2
• 1010 binary = 8+0+2+0 = 10 decimal

Octal (base 8):

• Digits 0-7
• Used in Unix permissions (chmod 755)
• Compact for representing groups of 3 bits

Hexadecimal (base 16):

• Digits 0-9 and A-F
• 2 hex characters = 1 byte
• Used for colors (#FF5733), memory addresses, debugging

Quick conversion:

• 4 binary bits = 1 hex digit
• 3 binary bits = 1 octal digit
• 1111 binary = F hex = 15 decimal

UUID/GUID:

• 128 bits, standardized format
• v4: random, most common
• v1: based on timestamp and MAC
• v7: timestamp + random, sortable

Alternatives:

• ULID: UUID-compatible, lexicographically sortable
• Snowflake ID: used by Twitter, 64 bits
• KSUID: K-Sortable UID
• NanoID: compact, customizable

Considerations:

• Collision: virtually zero probability for UUID v4
• Performance: UUID v4 isn't optimal for database indexes
• Security: UUID v1 exposes MAC address and timestamp

JSON (JavaScript Object Notation):

• Human-readable
• Web and REST API standard
• Types: string, number, boolean, array, object, null
• Limitation: no comments, no native dates

XML (eXtensible Markup Language):

• More verbose than JSON
• Schema (XSD) and namespace support
• Still used in SOAP, configs, documents

YAML (YAML Ain't Markup Language):

• Very readable, indentation-based
• Supports comments
• Popular for configurations (Docker, Kubernetes)

Data validation:

• JSON/XML/YAML validators
• Regex syntax checkers
• URL analyzers

Formatting and readability:

• Pretty-print JSON/XML
• Minification (production)
• Data comparison (diff)

Token inspection:

• JWT (JSON Web Token) decoder
• Claims and signature visualization
• Expiration verification

Tips:

• Use online tools for quick tests
• Prefer local tools for sensitive data
• Automate validations in your CI/CD

Secret management:

• Never commit secrets to code
• Use environment variables
• Secret managers (Vault, AWS Secrets Manager)

Authentication:

• JWT for stateless APIs
• OAuth 2.0 for authorization delegation
• Passwords hashed with bcrypt/Argon2

Input validation:

• Validate and sanitize all user input
• Use parameterized queries (SQL injection)
• Encode outputs (XSS)

HTTPS:

• Always use TLS in production
• HSTS (HTTP Strict Transport Security)
• Free Let's Encrypt certificates

REST (Representational State Transfer):

• HTTP-based, stateless
• Verbs: GET, POST, PUT, DELETE, PATCH
• Status codes: 2xx success, 4xx client error, 5xx server error

GraphQL:

• Flexible queries, single endpoint
• Client specifies exactly what data is needed
• Avoids over-fetching and under-fetching

gRPC:

• Protocol Buffers, binary and compact
• Bidirectional streaming
• Ideal for microservices

WebSockets:

• Real-time bidirectional communication
• Maintains persistent connection
• Use: chat, games, live updates

Essential commands:

• git clone/init: initialize a repo
• git add/commit: save changes
• git push/pull: sync with remote
• git branch/checkout: manage branches
• git merge/rebase: integrate changes

Best practices:

• Atomic commits with descriptive messages
• Feature branches for each feature
• Pull requests for code review
• Main branch protection

Complementary tools:

• GitHub/GitLab/Bitbucket: hosting and collaboration
• CI/CD: GitHub Actions, Jenkins, GitLab CI
• Automatic linters and formatters

Key metrics:

• Load time (First Contentful Paint)
• Time to Interactive (TTI)
• Largest Contentful Paint (LCP)
• Cumulative Layout Shift (CLS)

Frontend optimizations:

• JS/CSS minification
• Compression (gzip, Brotli)
• Image lazy loading
• Code splitting

Backend optimizations:

• Caching (Redis, Memcached)
• SQL query optimization
• Connection pooling
• CDN for static assets

Diagnostic tools:

• Chrome DevTools
• Lighthouse
• WebPageTest