Encoders, formatters, hashes and network tools

Base64, URL and HTML codecs, JSON tools, hashes, JWT inspection, UUIDs, regex, CIDR and related developer utilities. Inputs are processed in the browser.

FreeFastPrivateNo signupRuns in your browser

Encoding

Base64 Encode / Decode

Unicode-safe, URL-safe option, validation.

URL Encode / Decode

Component vs full-URL rules explained.

HTML Entity Encode/Decode

& < > " ' coverage with table.

Quoted-Printable (note)

Email encoding recipe.

Gzip Size Estimator

Compression ratio via CompressionStream.

Web

JWT Decoder

Header/payload, exp/iat humanized, alg warning.

JWT Signer (HS256)

Mint + verify test tokens locally, nothing leaves the tab.

URL Parser

Parts + params table + rebuild.

User-Agent Parser

Browser/OS/device heuristics table.

MIME Lookup

200+ ext→type table, search.

TLS/Cert Notes

Expiry/chain checklist for webmasters.

Security Headers Builder

CSP/HSTS template generator.

robots.txt Tester

Rule matcher for paths.

Sitemap Validator

URL count + date checks.

Color Format Snippets

HEX/RGB/HSL one-liners for CSS-in-JS.

JSON

JSON Formatter / Validator

Pretty/minify/sort, error location, NDJSON note.

JSON ⇄ CSV

Nested-path flatten option + table.

JSON Path Tester

dot-path lookup with wildcard * support.

Hash

MD5 / SHA-1 (legacy)

Pure-JS digests for checksums only.

SHA-256/384/512

SubtleCrypto async with fallback note.

Checksum Verifier

Recompute + compare (constant-time note).

IDs

UUID v4

Bulk crypto UUIDs.

ULID Decoder / Generator

Decode timestamp + mint crypto ULIDs locally.

Regex

Regex Tester

Flags, match list, groups, replace preview.

Common Regex Library

Email/URL/IPv4/date snippets, copy-ready.

Time

Unix Timestamp

Now/parse/format, ms auto-detect.

Cron Explainer

5-field explainer + next 5 runs, local time.

ISO/UTC Snippets

JS date one-liners.

Network

CIDR / Subnet Calculator

Network/broadcast/hosts with binary steps.

IP ⇄ Integer

IPv4 math with validation.

Bases

Binary / Hex / Dec / ASCII

Grouped conversions + roundtrip.

Code

HTML/CSS/JS Minify

Safe whitespace minifiers with savings %.

SQL Formatter (basic)

Keyword upper + indent, dialect note.

XML Formatter

Indent + validation note.

Diff Checker

Line diff for code review.

.env Generator

KEY=value with quoting rules.

.gitignore Builder

Stack presets → file.

Dockerfile Snippet

Static nginx recipe.

SemVer Checker

Range satisfiability explainer.

Content

Lorem / Placeholder

Words/sentences + image placeholder URLs.

Fake JSON Rows

Template → N rows, download.

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Why DevUtility?

Keep related encoding, formatting, validation, and network utilities together. Verify generated output before using it in production systems.

Processed locally in your device. Your file is not uploaded.

FAQ

Is it free?

Yes — every tool is free with no signup and no credits.

Is my data uploaded?

Selected files are processed in your browser and are not sent to a Tolari processing endpoint. Configured third-party scripts or resources may still load.

Does it work offline?

The app shell and deterministic tools can work after they are cached. Some file engines need an initial connection, and browser storage can be cleared.

Does it work on mobile?

Yes — touch-friendly, one-tap download, adaptive workers for weak devices.

How do you make money?

Ads may appear only after configuration and the required consent signal. No paywall or fake download buttons.

Guides

Base64 without tears (Unicode!) · JWTs: what decode proves and what it doesn't · CIDR notation in one page — practical, original explainers with examples.