Generators
29 free toolsUUIDs, passwords, lorem ipsum, QR codes, cron expressions, and more.
Generators produce the boilerplate and test data you need dozens of times a week: UUIDs and ULIDs, strong passwords and API keys, placeholder text, QR codes and barcodes, cron schedules, .gitignore and .htaccess files. Randomness comes from the browser's cryptographic generator, and the config generators emit the exact syntax the target program reads.
Everything here runs in your browser: files and text are processed locally and never uploaded.
All 29 tools
ULID Generator
Generate sortable unique identifiers (ULID)
UUID Generator
Generate v4 UUIDs in bulk with one-click copy
BIP39 Mnemonic Generator
Generate and validate BIP39 mnemonic seed phrases
Barcode Generator
Generate 1D barcodes (Code128, EAN, UPC, and more)
Printable Paper Generator
Make custom printable paper — lined, graph, dot grid, Cornell, music, and more
Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-512 hashes
HMAC Generator
Generate HMAC digests with a secret key
RSA / EC Key-Pair Generator
Generate RSA or EC key pairs as PEM
Placeholder Image Generator
Generate colored placeholder images at custom dimensions
QR Code Generator
Generate QR codes from text or URLs
WiFi QR Code Generator
Generate a QR code to join a WiFi network
Password Generator
Generate secure random passwords with crypto API
Lorem Ipsum Generator
Generate placeholder text in paragraphs, sentences, or words
Favicon Generator
Upload an image and generate favicons with custom shape, border, and padding
Crontab Builder
Build cron expressions visually with dropdowns and presets
Password Strength Analyzer
Check password entropy, strength, and crack time
Fake Data Generator
Generate realistic fake/mock test data and export to JSON, CSV, or SQL
Sample File Generator
Generate real, valid sample/dummy files at an exact size
API Key Generator
Generate secure API keys and secrets in various formats
bcrypt Hash & Verify
Generate and verify bcrypt password hashes
.htpasswd Generator
Generate Apache .htpasswd entries with bcrypt or SHA
TOTP Generator & Validator
Generate and validate time-based one-time passcodes
Random Number Generator
Cryptographically random numbers, dice rolls, and coin flips
Signature Generator
Draw or type a signature and download it as transparent PNG or SVG
Invoice Generator
Create professional PDF invoices with automatic totals
Business Name Generator
Generate brandable business names from curated word banks
Resume Builder
Build an ATS-friendly resume and download a real-text PDF
Chart Maker
Paste CSV or JSON and download a bar, line, pie, or scatter chart as PNG
File Checksum Verifier
Hash a file of any size and compare it to an expected checksum
Guides
From the blog: the mechanisms, standards, and edge cases behind these tools.
- Is Math.random() Random Enough? (Usually No) Math.random vs crypto.getRandomValues: why V8 output is predictable from a few samples, how modulo bias loads a dice roll, and the JavaScript shuffle bug. Sep 5, 2026 · uses UUID Generator, Password Generator, API Key Generator +1
- .htpasswd Hash Formats: bcrypt vs apr1 (MD5) vs {SHA} vs crypt, and What nginx Actually Accepts htpasswd hash formats explained: bcrypt $2y$, apr1 MD5, {SHA} and crypt(3) — how to tell them apart, and which ones Apache, nginx, Caddy and Traefik accept. Sep 14, 2026 · uses Password Generator, bcrypt Hash & Verify, .htpasswd Generator
- The WIFI: QR Code Format, Explained (WPA3, Hidden Networks, and the Semicolon Problem) WiFi QR code format explained field by field: WIFI:T:WPA;S:..., backslash escaping, WPA3 and hidden networks, and why the code won't scan on an iPhone. Sep 13, 2026 · uses QR Code Generator, WiFi QR Code Generator, Password Generator
- Password Entropy Explained: Why Strength Meters Disagree The entropy formula every strength meter starts from, why it overrates human-chosen passwords, how zxcvbn-style estimators differ, and the real math behind diceware and BIP39 passphrases. Aug 3, 2026 · uses BIP39 Mnemonic Generator, Password Generator, Password Strength Analyzer
- How bcrypt Actually Works: Salts, Cost Factors & Why You Never MD5 a Password A developer-friendly explanation of bcrypt — why password hashing is different from regular hashing, what the salt and cost factor in a $2b$ string mean, how deliberate slowness defeats brute-force attacks, and why MD5 and SHA-256 are the wrong tools for passwords. Jun 25, 2026 · uses Password Generator, Password Strength Analyzer, bcrypt Hash & Verify
- UUID vs ULID: v4, v7, and Which ID You Should Actually Use A practical comparison of UUID and ULID for generating unique IDs — how UUIDv4, UUIDv7, and ULID differ, why random IDs wreck database index performance, what "sortable" really buys you, and a clear decision guide for picking the right identifier in 2026. Jun 24, 2026 · uses ULID Generator, UUID Generator, API Key Generator
- XOR, ROT13 and Caesar: Why Toy Ciphers Still Matter XOR cipher explained — why ROT13 and Caesar are toys, why XOR sits inside AES, HMAC and ChaCha20, and how a repeating-key XOR is broken in a few seconds. Sep 6, 2026 · uses HMAC Generator, Random Number Generator
- Base64 vs Base32 vs Base58: Choosing an Alphabet Humans Can Retype Three encodings of the same bytes, three different design goals. Why base32 is case-insensitive and 60% larger, which four characters Bitcoin deleted from base64 and why, why your TOTP secret is always 32 uppercase characters, and where each decoder is deliberately more permissive than RFC 4648 allows. Aug 31, 2026 · uses ULID Generator, TOTP Generator & Validator
- How to Verify a SHA-256 Checksum (and What It Proves) How to verify a SHA-256 checksum on Windows, macOS and Linux, why a matching hash proves less than you think, and what to check when it does not match. Aug 27, 2026 · uses HMAC Generator, File Checksum Verifier
- How to Scan a QR Code From a Screenshot on Your Computer (No App, No Upload) The fastest way to decode a QR code from a screenshot without a phone app — plus why "just use Google Lens" is bad advice when the code holds a WiFi password, and the technical reasons some codes refuse to scan. Jul 26, 2026 · uses QR Code Generator, WiFi QR Code Generator
- How TOTP 2FA Codes Actually Work: Shared Secrets, Time Steps & QR Codes A developer-friendly breakdown of TOTP — the six-digit codes from authenticator apps. How the shared secret gets into your phone via a QR code, why the code changes every 30 seconds without any network connection, what HMAC and the time step do, and how the server verifies it. Jun 27, 2026 · uses QR Code Generator, TOTP Generator & Validator
- How to Total a Timesheet with Breaks and Overnight Shifts (and Convert 7:45 to 7.75 Hours) Step-by-step timesheet math: subtract unpaid breaks, handle shifts that cross midnight, apply daily or 40-hour overtime, and convert minutes to decimal hours. Oct 16, 2026 · uses Invoice Generator