Best Browser DevTools in 2026

Dia is a specialized browser engineered to optimize professional workflows by intelligently organizing information and proactively suggesting relevant content. It acts as a central hub, integrating with various work tools like GSuite, Slack, Notion, and GitHub to provide a unified view of tasks and information. Dia aims to reduce context switching and information overload, allowing users to concentrate on deep work. The browser features include a "Morning Brief" for daily overviews, "Proactive Suggestions" that surface next steps, and an AI-powered search that answers questions by analyzing context across connected applications. It also offers features for better meeting preparation, distinct work and personal profiles, and advanced tab management. Dia prioritizes user privacy with local data storage, end-to-end encryption for synced data, and strict controls over data sharing for product improvement.

Comet is Perplexity's AI-powered web browser. It builds Perplexity's answer engine directly into the browser, letting you ask questions about any page, summarize articles, and use an AI assistant that can take actions across your tabs. It is positioned as an agentic browser that completes tasks, not just one that displays pages.

Requestly is an open-source, lightweight API client and web proxy designed for modern developers to build, test, and debug APIs efficiently. It offers both a browser extension for instant, in-browser functionality and a more powerful desktop application for Mac (with other platforms implied) to handle web, mobile, and desktop app API interactions. Beyond just an API client, Requestly functions as a robust HTTP interceptor and web debugger. It allows developers to intercept and modify network requests, headers, and API responses in real-time. This includes injecting custom scripts (JavaScript/CSS), mocking API responses to build frontends without a backend, simulating edge cases, and redirecting requests. It aims to streamline development workflows by providing a comprehensive tool for API development, testing, and debugging, reducing the need to juggle multiple tools. Requestly also emphasizes collaboration and enterprise-readiness with features like team workspaces, Git synchronization for API collections, role-based access control, and robust security measures including SOC-II compliance, SSO, and data encryption. It positions itself as a powerful, open-source alternative to more 'bloated' closed-source solutions, offering a fast, flexible, and secure environment for API development and debugging.

Agent Browser enables AI agents to navigate, click, type, and interact with real web browsers using ASCII wireframes, a text-based representation where interactive elements are numbered for efficient token usage. Instead of processing heavy screenshots, AI models receive structured wireframes that maintain semantic clarity while minimizing cost and latency. Built on Playwright, it integrates with MCP clients (Claude Desktop, Cursor), the Vercel AI SDK, and offers an interactive CLI for manual testing.

Grayscale for Safari is a Safari extension designed to reduce visual distractions and promote focused browsing by rendering web content in grayscale. It's available for Mac, iPhone, and iPad, offering a consistent experience across Apple devices. The tool aims to make online feeds less stimulating and help users reduce screen time and combat doomscrolling by making visually rich content less engaging. This extension is ideal for individuals looking to improve their digital well-being, reduce addiction to certain websites, or simply create a calmer browsing environment. It prioritizes user privacy with no tracking, analytics, or account requirements. Users can easily control the extension with a one-tap toggle from the Safari extension menu and customize it by whitelisting specific domains to remain in color.

BrowserBash is a free, open-source CLI tool that turns plain-English descriptions into automated browser tests, using an AI agent to drive a real browser instead of writing selector-based code. Tests are stored as committable markdown files and produce CI-friendly exit codes and NDJSON output, with optional video recording and a run-history dashboard. It is built for QA engineers and developers who want browser automation without brittle CSS selectors.

Archify is a free, open-source browser extension that helps developers quickly understand the architecture behind any web page. By simply hovering over elements, it reveals the frameworks, UI libraries, APIs, analytics, hosting, and security components that make up the application, all processed locally with nothing sent to external servers. Each detection includes a confidence score, and unknown elements are honestly reported as unknown. The tool addresses the growing challenge of understanding modern software, which is increasingly complex despite being easier to build. Developers spend a significant portion of their time comprehending code rather than writing it, especially in the browser. Archify surfaces the system behind the interface: components, network calls, form listeners, third-party scripts, payment processors, and more. It integrates seamlessly into the browser workflow, providing instant insights without switching to DevTools or reading documentation. Archify is built for frontend engineers tracing bugs, QA engineers needing technical context for reports, and technical founders analyzing competitor stacks. It detects 100+ fingerprints across frameworks (React, Next.js, Vue, Angular, etc.), UI libraries, analytics pixels, commerce platforms, CMS, hosting providers, and security defenses. Every reading is verifiable with evidence, and the tool never fabricates information.

ChatHop is a browser extension that lets you transfer conversation context between different AI chat services with a single click. Instead of manually copying and pasting when you hit a wall or want a second opinion, ChatHop carries the entire conversation, including history, into a fresh chat on the AI you choose. You can also copy the full conversation in plain text or Markdown to paste into documents, emails, notes, or other apps. Built with privacy in mind, ChatHop only reads conversation data when you initiate a transfer or copy action. It never sends chat text to its billing service, never uses your chats for advertising or profiling, and never sells your data. The extension works with major AI chat platforms and requires no account for the free tier. A free plan gives you 20 uses per month, with a Pro subscription available for unlimited use.

Tinkerfont is a browser extension (for Chrome and Firefox) that lets you inspect, replace, and test fonts on any live website. It is designed for designers, developers, and typography enthusiasts who want to see how a typeface performs across real content, layouts, and breakpoints without editing CSS or leaving the browser. The tool includes a right-click font inspector, a scanner to list every font in use on a page, and a swap feature that offers a large selection of fonts from Bunny Fonts or custom uploaded files. Changes can be scoped to specific areas of a page, and all rules persist per hostname in local storage, making it easy to iterate on staging or reference sites over multiple sessions. Tinkerfont does not require an account, collects no data, and is free to use with optional supporter contributions.

KanjiLens is a browser extension designed to help Japanese learners master kanji through immersion. It allows users to read their favorite manga and novels online, providing instant kanji lookup by hovering over any character to see its reading and meaning. This eliminates the need to break reading flow for dictionary lookups. The tool also features one-click image translation, utilizing OCR technology to seamlessly translate text within manga panels and other images, making raw Japanese content more accessible. An integrated Spaced Repetition System (SRS) allows users to save new words to personalized flashcard decks, aiding long-term memory retention. Additional features include right-click scanning, custom mnemonics, and customizable settings, making it ideal for anyone looking to learn Japanese by engaging with native content.