Developer01
JSON Fix
Repair malformed JSON and turn it into clean, readable data.
Browser-based utilities
Tools for everyday digital work
Twenty-four focused utilities for developer data, text, images, URLs, CSV, HTML, and CSS. Tools process input in this browser and do not upload it to a 77 Toolkit server.
24 tools · 4 categories
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Search the full collection or browse by category.
Developer
8 toolsDeveloper02
JSON Diff
Compare two JSON documents and inspect added, removed, and changed values.
Developer03
Timestamp Converter
Convert Unix timestamps and local dates while keeping an eye on the current time.
Developer04
JWT Decoder
Decode JWT headers and payloads locally without sending tokens to a server.
Developer05
Base64 Encoder
Encode or decode UTF-8 text with standard and URL-safe Base64.
Developer06
Regex Tester
Test regular expressions, inspect capture groups, and highlight every match.
Developer07
UUID Generator
Generate secure UUID v4 values in batches and validate existing UUIDs.
Developer08
Hash Generator
Calculate SHA-256, SHA-384, or SHA-512 hashes for text and local files.
Text
5 toolsText09
Text Clean
Remove copied rich-text and AI formatting while preserving readable structure.
Text10
Text Diff
Compare text line by line with a clear view of additions and removals.
Text11
Case Converter
Switch text between common writing and programming case styles.
Text12
Line Processor
Clean, sort, reverse, number, prefix, or deduplicate lists of lines.
Text13
Word Counter
Measure words, characters, sentences, lines, reading time, and common terms.
Image
6 toolsImage14
Color Spectrum
Extract dominant colors, inspect pixels, and export palettes from an image.
Image15
Image Compressor
Reduce image file size locally with an adjustable quality setting.
Image16
Image Resizer
Resize images to exact dimensions while optionally preserving aspect ratio.
Image17
Image Format Converter
Convert images between PNG, JPEG, and WebP entirely in the browser.
Image18
Color Contrast Checker
Check foreground and background colors against WCAG contrast targets.
Image19
Image Metadata Remover
Strip EXIF and other metadata by safely re-encoding an image locally.
Web
5 toolsWeb20
URL Parser
Break an absolute URL into its origin, path, query parameters, and fragment.
Web21
URL Encoder
Encode or decode URL components without sending addresses to a remote service.
Web22
CSV ↔ JSON Converter
Convert quoted CSV records and JSON object arrays in either direction locally.
Web23
HTML Entity Encoder
Encode HTML-sensitive characters or decode named and numeric character references.
Web24
CSS Unit Converter
Compare px, rem, em, vw, and vh values using explicit layout assumptions.
No tools match that search.
Original editorial content
Understand the work behind the tool
Practical explanations, review steps, and limitations for developer, web, text, and image workflows.
Linux diagnostics
9 min read · Read guide →Why a command works outside tmux but gets permission denied inside
A process-focused workflow for comparing users, groups, environment variables, path permissions, ACLs, and mount context before changing access.
Git and GitHub
8 min read · Read guide →Why GitHub shows the wrong commit author and how to fix it
Understand author, committer, and pusher identities; diagnose email-based attribution; and configure local or automated commits safely.
Developer data
7 min read · Read guide →How to repair invalid JSON without changing its meaning
A careful workflow for fixing JSON syntax, reviewing inferred changes, and validating the result before it returns to an application.
How the collection is maintained
Useful output needs a reviewable method
Every published tool combines working browser functionality with task-specific guidance and explicit limitations.
Local by design
Text and selected files are processed with browser APIs. Tools do not fetch pasted URLs or send input to a 77 Toolkit backend.
Specific, not generic
Each page explains its own workflow, assumptions, failure cases, and better alternatives instead of repeating one template description.
Built for verification
Input stays visible, results can be reviewed before copying, and the production build checks metadata, links, page depth, and crawlability.
Read the editorial and testing policyRead the accessibility statement
About 77 Toolkit
77 Toolkit collects small, useful browser tools in one place. Text, tokens, images, URLs, and tabular data are processed locally whenever the browser provides the required capability. Learn how the site is built and maintained.