Regex Tester & Debugger
Test regular expressions with real-time syntax highlighting, capture groups, flags (g, i, m, s, u), and substitution replacement preview.
Popular
Capture Groups
Flags
🔒 100% Client-Side • Zero Data Sent to Servers
The Ultimate Swiss Army Knife for Modern Developers
Eliminate the hassle of visiting dozens of separate single-purpose websites. Test regex, parse crontabs, encode & decode JWTs, generate cryptographically secure passwords, and convert Base64 — completely offline and safe in your browser.
No Registration / No Login
100% In-Browser Execution
Free Forever (Ad Supported)
Local Diagnostic Tracing
Essential Developer Tools
Battle-tested utilities engineered for speed, privacy, and productivity.
Cron Expression Parser
Convert standard 5-part and 6-part cron expressions into plain human-readable English schedules with next scheduled execution timestamps.
Essential
5 & 6 Part
Next Runs
Client-Side JWT Decoder
Safely inspect JSON Web Tokens without risking server token leaks. Parses header, payload claims, expiration countdown, and timestamp dates.
Privacy Safe
Claims Formatter
Expiry Check
JWT Encoder & Signer
Generate custom signed HS256/unsigned JWT tokens for mock authentication, API testing, and microservice payload simulation.
HS256
Custom Secret
Mock Auth
Base64 Encoder & Decoder
Encode and decode UTF-8 text, binary data, and Data URIs with instant toggle between standard RFC 4648 Base64 and URL-Safe Base64 variants.
UTF-8 Clean
URL-Safe
Data URI
Random Password Generator
Generate cryptographically secure randomized passwords with customized length, uppercase, lowercase, numbers, and symbols with live entropy evaluation.
Crypto API
Custom Characters
Entropy Meter
JSON Formatter & Minifier
Format, validate, prettify, and minify messy JSON data with clear syntax error indicators and one-click copy options.
Validator
Minifier
Format 2/4 Spaces
UUID v4 & GUID Generator
Bulk generate RFC 4122 compliant version-4 UUIDs with options for uppercase formatting, hyphens, and bulk copy.
Bulk Mode
RFC 4122
GUID
Client-Side Hash Generator
Compute SHA-256, SHA-512, SHA-1, and MD5 cryptographic digests instantly in your browser using the native Web Crypto API.
SHA-256
SHA-512
Web Crypto
Unix Epoch Timestamp Converter
Convert seconds & milliseconds epoch timestamps to human dates, UTC time, ISO 8601 strings, and local timezone formats.
ISO 8601
Seconds / MS
Relative Time
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Built Different: Private by Architecture
Why seasoned engineers choose Swiss Army Dev Tool over online alternatives.
Zero Server Transmission
Every operation runs locally in your browser sandbox using modern JavaScript and Web Crypto APIs. Your tokens, passwords, and sensitive regex never touch a wire.
Instantaneous Feedback
No network latency, no rate limits, and no CAPTCHAs. Everything recomputes dynamically on every keystroke with microsecond response times.
No Accounts or Paywalls
No email signup, no trial periods, and no tracking cookies. Fully free and supported unobtrusively through non-intrusive developer advertisements.
Transparent Local Auditing
Audit your own usage logs saved in your browser's LocalStorage. Inspect operations or clear them with a single click at any time.
Why Developers Need Client-Side Web Utilities
Modern software engineering demands quick iterations. Whether you are debugging a distributed OAuth2 JWT token, deciphering a confusing cron schedule in a Kubernetes deployment manifest, or validating regex patterns against sample JSON payloads, switching context to write custom throwaway scripts wastes valuable time.
However, traditional web-based developer tools pose severe security risks. Pasting bearer tokens, API secrets, or proprietary data into unknown third-party websites can expose your organization to credential leakage, compliance violations, and data exfiltration.
Swiss Army Dev Tool was created to solve this dilemma: an ultra-fast, clean, and comprehensive development workstation where every single computation is strictly executed client-side.
Key Engineering Principles:
- Cryptographic Randomness: Password generation relies exclusively on
crypto.getRandomValues(), providing true cryptographically strong pseudo-random numbers rather than predictableMath.random()math. - RFC-Compliant Encoding: Base64 and URL encoding accurately handle multi-byte UTF-8 character sets, emojis, and binary payloads without corrupting character encodings.
- High-Fidelity Cron Parsing: Supports standard UNIX 5-field syntax (minute, hour, day of month, month, day of week) and expanded 6-field formats with exact future run timestamp calculations.
Frequently Asked Questions
Common questions regarding privacy, security, and usage.
Are my passwords or JWT tokens sent to any server?
Never. All computation is executed purely in your browser's JavaScript engine. You can inspect your browser's Network tab in DevTools or even disconnect your internet entirely — every tool works 100% offline.
Why is there no sign up or login?
We believe developer utilities should be friction-free. You should never have to surrender your email address, confirm accounts, or remember another password just to format JSON or parse a cron tab.
How does the website make money?
Swiss Army Dev Tool is 100% free to use. Server hosting, domain management, and ongoing development are funded through clean, non-intrusive Google advertisements shown on each page.
How can I report a bug or request a new tool?
Click the "Feedback" button in the navigation header or email us directly at [email protected]. We actively review all suggestions!