Developer Tools
Formatters, encoders, data tools, network utilities, markup tools, and API-adjacent utilities.
Most Used Tools
Ranked from tool metadata, popularity signals, and category relevance.
Base64 Encoder & Decoder
Encode text, files, and images to Base64 format. Decode Base64 back to original content. Browser-based with image preview and file upload support.
CSV Column Matcher
Fuzzy match two CSV columns online free — reconcile messy datasets with Levenshtein distance. Find near matches, typos, and inconsistencies across CSV columns in your browser with no uploads.
JSON Array Diff Tool
Compare two JSON arrays or deeply nested objects instantly in your browser with a recursive diff engine. Detect added, removed, and modified keys in API responses, configuration files, and massive enterprise datasets — all locally with zero uploads.
JSON Formatter
Format, beautify, minify, and validate JSON data instantly with syntax highlighting, error detection, and tree view.
Recently Added
This section updates automatically when a new tool is assigned to Developer Tools.
JWT Decoder & Local Verifier
Decode and inspect JSON Web Tokens (JWT) entirely in your browser. Verify signatures locally with HS256/384/512, RS256/384/512, or ES256/384/512. Analyze claims, validate expiration times, check for security risks, and simulate clock skew with 100% offline, zero-knowledge privacy.
Markdown Checkbox List Extractor
Extract checked, unchecked, or all tasks from Markdown documents. Supports Obsidian, Notion, GitHub, GitLab, Logseq exports, and more. Fast regex-based parsing, Web Worker offloading, 100% browser-based — no uploads, complete privacy.
CSV Column Matcher
Fuzzy match two CSV columns online free — reconcile messy datasets with Levenshtein distance. Find near matches, typos, and inconsistencies across CSV columns in your browser with no uploads.
JSON Array Diff Tool
Compare two JSON arrays or deeply nested objects instantly in your browser with a recursive diff engine. Detect added, removed, and modified keys in API responses, configuration files, and massive enterprise datasets — all locally with zero uploads.
Developer Tools
8 tools available
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About Developer Tools
Developer Tools is the home for code-adjacent work: formatting JSON, encoding data, matching CSV columns, editing Markdown, and checking IP lists. These are the small utilities developers reach for while debugging APIs, cleaning data, or preparing technical content.
Every tool runs in your browser, so snippets, payloads, and configuration data stay on your device. The category stays focused on technical data formats and developer workflows, while plain text and marketing list tools now live in their own clearer hubs.
This category currently includes 8 tools across 5 active subcategories. Add a new tool with the correct category and subcategory metadata, and this page updates automatically.
Related Categories
Related categories are ranked from shared input types, output types, popularity signals, and tool metadata.
Text & List Tools
Text counters, converters, line tools, list comparison, list cleanup, and text generators.
Security & Privacy Tools
Encryption, password, key, hash, checksum, redaction, and metadata privacy tools.
Calculators
Math, finance, date, unit, and numeric calculators.
SEO & Marketing Tools
Keyword tools, domain tools, email list tools, campaign utilities, and content marketing helpers.
Frequently Asked Questions
What belongs in Developer Tools?
Developer Tools covers code, structured data, encoders, network inputs, Markdown for documentation, and API-adjacent tasks. If a tool mainly processes plain words or generic lists, it belongs in Text & List Tools instead.
Are developer tools processed locally?
Yes. These utilities run in your browser, so API responses, JSON files, encoded strings, and network lists are processed on your device without uploads.
Why are some list tools not in Developer Tools anymore?
The migration separates developer data workflows from everyday list cleanup. JSON, CSV, encoding, Markdown, and IP tools remain here; generic line sorting and deduplication now live in Text & List Tools.
Do I need to create an account?
No. All 8 tools in Developer Tools are available instantly with no sign-up.
What if I need a tool that is not in this collection?
Use the Suggest a Tool page to request it. Once a new tool is added with Developer Tools metadata, this page updates automatically.