Practical guides on the formats, algorithms, and tools developers and teams use every day. No filler, no fluff: just clear explanations with real examples.
A head-to-head comparison of the best free PDF tools. See how AlteredIdea's 100% private, zero-upload tools stack up against Smallpdf and iLovePDF.
Every method for reducing PDF file size explained: compression, removing pages, downsampling images, stripping metadata, and re-exporting from source. Which approach to use and when.
Most tools charge you or use expensive AI to remove backgrounds. Here's how to remove image backgrounds instantly in your browser using alpha masking, with zero privacy risks.
UUID and GUID are the same thing. GUID is Microsoft's name for UUID v4. This guide explains the difference in plain English, covers UUID versions v1 through v7, and shows when to use each one.
A curated list of free developer tools that run entirely in your browser: no files uploaded, no server needed, no internet required after the page loads. Works on planes, behind firewalls, and on sensitive documents.
Learn what a JWT is, what the three parts contain, when to decode vs. verify, and how to use a JWT decoder online safely. Includes a step-by-step decoded example and security guidance.
You do not need expensive software to invoice clients professionally. A step-by-step guide to creating, sending, and tracking invoices without subscriptions.
UTM parameters show which campaigns and links drive traffic. Here is how to build them correctly and avoid the mistakes that pollute your analytics data.
A Content Security Policy prevents XSS attacks by telling browsers which resources are allowed to load on your page. A practical guide to writing and deploying your first CSP.
AES is the encryption standard used by HTTPS, WhatsApp, and FileVault. A plain-English guide covering how it works, cipher modes, a Node.js code example, and AES vs ChaCha20.
RSA key pairs are the foundation of public-key cryptography: SSH access, TLS certificates, code signing, and encrypted communication all rely on them. A practical guide.
XOR is the simplest encryption operation in computing. Understanding how it works explains the foundation of symmetric encryption, stream ciphers, and one-time pads.
Choosing between px, rem, em, and other CSS units affects accessibility, responsiveness, and maintainability. A clear guide to what each unit does and the right context for each.
Large images are one of the biggest causes of slow page loads. Here is how compression works, which format to choose, and how to compress images without visible quality loss.
You do not need Microsoft Office or a paid subscription to convert DOCX files to PDF. Several free, private methods work in any browser on any device.
A complete guide to CSS gradients with 10 copy-paste examples, animated gradient tutorial, and performance tips. Use a CSS gradient generator to build them visually.
Unix timestamps appear in logs, databases, APIs, and code everywhere. A plain-English explanation of what they are, why they exist, and how to convert them.
A complete jwt debugger guide: decode tokens in Node.js and Python, compare HS256 vs RS256 vs ES256, implement refresh token patterns, fix common errors, and choose the right JWT library for your stack.
URLs can only contain a limited set of characters. URL encoding converts unsafe characters into a format that can be safely transmitted. A developer's guide to percent-encoding.
How to convert image to PDF from any device: step-by-step guide covering JPG, PNG, HEIC from iPhone, multi-page scan workflows, print quality settings, and format comparison.
Resizing images incorrectly degrades quality and creates pixelated results. A guide to resizing images the right way: maintaining aspect ratio, choosing dimensions, and preserving sharpness.
How to generate a secure password: entropy explained, NIST guidelines, password manager comparison, and why multi-factor authentication completes the picture.
YAML and JSON both represent structured data but have different strengths. A practical guide to choosing between them and converting between the two.
JSON formatter online: format, validate, and debug JSON in your browser. Common errors explained, JSON Schema examples, and API response debugging guide.
How to split a PDF into pages or sections without software. Use cases for lawyers, accountants, and HR, plus a comparison with Adobe Acrobat.
How to password protect a PDF with AES-256 encryption. Use cases for legal, HR, and finance teams, and how to share the password securely.
Checksums let you verify that a downloaded file is exactly what the publisher intended. A plain-English guide to MD5, SHA-256 checksums and how to use them.
Regex for beginners: learn the patterns you will actually use. Literals, quantifiers, anchors, real-world examples, and a guide to testing your patterns.
Storing plaintext passwords is a critical security flaw. Bcrypt is the industry standard for password hashing. Here is how it works and how to use it correctly.
How QR codes work, what they can store, and how to create one. Use-case guide, error correction explained, and a print checklist before you deploy.
Remove image background without Photoshop in seconds using AI. Step-by-step guide, before and after examples, and tips for clean, professional results.
SHA-256 vs MD5: which hash algorithm to use and when. Comparison table, real-world examples, and a plain-English guide to cryptographic hashing.
Most PDF merging services upload your files to a stranger's server. This guide explains the privacy risk in plain terms, shows how browser-based merging works, and walks through the 5-step process with AlteredIdea's free PDF Merger.
What is Base64 encoding? A plain-English guide covering how it works, where it appears, JavaScript code examples, JWTs, and when not to use it.
PNG vs JPG vs WebP vs AVIF: a plain-English guide to choosing the right image format, with a comparison table, quality settings, and real-world advice.
How to compress a PDF without losing quality: what makes PDFs large, which settings preserve sharpness, target file sizes, and how to verify the result.