Best Web Development / Testing Tools in 2026

Fast, free dev tools that run 100% client-side no signup.

Key DevNestTools features:

Free to Use Wide Range of Utilities No Installation Required Simple and Clean Interface

Tap a thing and the counter resets. A quiet, local-first day counter for the things you keep meaning to do. No account needed, no spreadsheet.

Key cobwebs.app features:

Day counters No account needed Cross-device sync

Try for free freemium €14 / Annually (Plus) Sponsored

All-in-one website audit platform. Analyze accessibility, SEO, performance, security, and content quality in a single scan. Get actionable insights and comprehensive reports.

Key Blyxo.app features:

Accessibility Testing SEO Analysis Performance Monitoring Security Scanning

freemium £0.5 (Per Page)

Free online JSON and XML tools. Format, validate, convert, diff, generate TypeScript interfaces, Pydantic models, and more. 100% client-side, instant, private.

Key JsonUtils.app features:

Ease of Use Free Access Browser-Based Convenience Multiple JSON Utilities

free

Freeformatter is a platform that contains free online tools for developers, including formatters (json, html, xml, sql, etc.), minifiers (css, javascript), compactors, validators, and much more.

Key FreeFormatter features:

Wide Range of Tools User-Friendly Interface No Installation Required Free to Use

Efficient and effective accessibility testing is here.

Key axe DevTools features:

Comprehensive Accessibility Testing Integration with Development Tools Automated Testing Detailed Issue Reporting

Free online JSON viewer and formatter tool. Transform, validate and analyze JSON data instantly.

Key Easy JSON Viewer features:

Interactive JSON Tree Viewer Fast JSON Formatter & Validator Search & Download JSON Files

free

Convert files like images, video, documents, audio and more to other formats with this free and fast online converter.

Key Online Convert features:

User-Friendly Interface Variety of Formats No Software Installation Free to Use

Mobile money, reinvented. Deposit, withdraw, pay bills for free. Send for only 1%.

Key Wave features:

Cost User-Friendly Interface Integrated Platform Cloud-Based

Open Source

All-in-one JSON toolbox for developers and data analysts. Quickly format, compress, validate, and convert JSON files. 100% free and no signup required.

Create custom QR Codes with Logo, Color and Design for free. This QR Code Maker offers free vector formats for best print quality.

Key QRcode-monkey.com features:

Free to Use Customization High-Quality Output Ease of Use

Consider the Siteimprove Intelligence Platform the newest member of your team.

Key Siteimprove features:

Comprehensive Website Analytics User-Friendly Interface Accessibility Evaluation Automated Reporting

Screen Resolution Manager is one of the robust and streamlined desktop applications that come with an easy way to adjust your screen resolution.

Key Screen Resolution Manager features:

User-Friendly Interface Custom Profiles Multi-Monitor Support

Free online JSON formatter with validation, minify, and tree view. Professional JSON tools for developers.

Key JSON Format Online features:

JSON Formatting JSON Validation JSON Conversion Developer Friendly UI

free