Open-source alternatives to Size Limit

Pageres is an automated web page capturer and command line interface that renders HTML content and websites into images. It uses a headless Chromium browser to generate screenshots of full pages or specific elements across multiple screen resolutions. The tool allows for the simulation of different device dimensions to verify responsive design and the creation of visual snapshots for UI regression testing. It supports the capture of protected pages by passing custom HTTP headers, cookies, and basic authentication credentials. The system includes capabilities for page content manipulation thr

sitespeed.io is a web performance analysis tool and monitoring system designed to measure website speed and Core Web Vitals using real browsers. It functions as a performance regression suite and a browser performance monitor, enabling the enforcement of performance budgets to detect and block speed regressions. The project is distinguished by its real device testing framework, which executes performance audits on physical Android and iOS hardware via USB connections. It includes a specialized tool for generating and comparing HTTP Archive files to diagnose network bottlenecks, alongside inte

Lighthouse CI is a continuous integration tool designed to automate web audits and detect performance, accessibility, and SEO regressions between code commits. It functions as a web performance regression suite that enforces resource budgets and runs automated quality checks during the software development lifecycle. The system distinguishes itself through the ability to block code merges if performance metrics fall below defined quality thresholds. It provides mechanisms for commit-to-commit comparison and cross-version site analysis to pinpoint specific resource improvements or regressions.

This project is an algorithmic performance benchmarking tool and execution cycle simulator. It functions as a complexity analysis framework that measures code execution speed using simulated clock cycles to evaluate algorithmic efficiency against established performance baselines. The tool provides deterministic measurements of computational work and time complexity by tracking virtual clock cycles rather than real time. It utilizes a threshold-driven test suite to validate whether specific code implementations meet required performance cycle targets. The framework covers execution speed pro

source-map-explorer is a source map bundle analyzer that visualizes the space usage of bundled JavaScript files. It functions as a bundle size auditor and visualizer, using source maps to identify which original modules and files occupy the most space within a production bundle. The tool generates an interactive treemap to represent bundle composition and calculates compressed gzip sizes to estimate actual network transfer costs. It further serves as a code coverage mapper by overlaying execution data onto source maps to identify unused code segments that can be deferred or split. The utilit

Webpack bundle size analyzer is a command-line tool and diagnostic utility that inspects compiled Webpack build output to report the exact file size and percentage contribution of each individual module and package. It operates via JSON-driven static analysis against build output files, parsing and traversing abstract syntax trees and dependency graphs to calculate precise byte weights without altering original execution code. The tool sorts and aggregates parsed module metrics by file size and percentage share to highlight the largest bundle contributors. It provides terminal stream output a

Pylint is a static code analysis tool for Python that checks source code for errors, coding standard violations, and code smells without executing the program. It parses code into an abstract syntax tree and walks the tree to detect issues, enforces configurable style rules and naming conventions, and identifies duplicate code blocks by comparing tokenised source sequences. The tool also includes an inference engine that deduces variable types by simulating code paths, enabling deeper analysis even in untyped code. What distinguishes Pylint is its plugin-based checker architecture, which allo

Terrascan is an infrastructure as code security scanner and cloud configuration auditor designed to detect security violations and compliance risks in cloud templates and Dockerfiles before provisioning. It utilizes the Open Policy Agent to evaluate infrastructure templates against both standard security policies and custom organizational rules. The project functions as a security guardrail within build pipelines, blocking risky deployments by integrating scanning logic directly into CI/CD workflows. It also includes a container registry vulnerability scanner that collects vulnerability data

React Doctor is a static analysis tool for React codebases designed to identify security, performance, and architectural issues. It functions as a codebase health diagnostic engine that produces numeric health scores and structured diagnostics to improve maintainability. The tool features an incremental code scanner that evaluates only the files changed between branches or staged in the working tree to provide fast feedback. It is designed to operate as a quality gate within CI pipelines, allowing for the enforcement of codebase health standards by failing builds on critical errors. The anal

Pa11y is an automated web accessibility auditor and WCAG compliance scanner. It functions as a headless browser testing tool and a Node.js accessibility API that identifies barriers for users with disabilities using automated rules and industry standards. The project provides a programmable interface for triggering audits and retrieving structured result objects within JavaScript applications. It distinguishes itself through capabilities such as user interaction simulation, page state synchronization, and the ability to restrict test scopes using CSS selectors to audit specific page regions.

Newman is a headless API client and command line tool for executing Postman collections. It serves as an API test automation tool and execution engine that allows users to run predefined sets of API requests without a graphical interface. The project differentiates itself as a data-driven testing engine, capable of iterating through request sequences using external JSON or CSV files to validate multiple sets of input values. It also functions as an API execution reporter, utilizing a plugin-based interface to output results in formats such as JSON and JUnit. The tool covers broad capability

Gitleaks is a static analysis security tool and secret detection engine designed to find hardcoded passwords, API keys, and authentication tokens. It functions as a Git secret scanner that analyzes both local file systems and Git commit history to prevent credential leaks. The tool distinguishes itself through a decoding pipeline that transforms base64 and hex strings into plaintext to find obfuscated secrets. It further reduces false positives using proximity-based validation and fingerprint-based suppression to filter out known or baseline findings. The system covers a broad range of detec

Phan is a static analyzer and type checker for PHP that identifies bugs and type incompatibilities without executing the code. It serves as a quality gate for continuous integration pipelines and a tool for verifying type safety, specifically checking union types, generics, and array shapes. The project is distinguished by its use of a background daemon and Language Server Protocol implementation, which provide real-time diagnostics and navigation within editors. It also features a baseline-based suppression system that allows developers to record existing errors in a snapshot file to focus e

SonarQube is a static code analysis platform used to scan source code and infrastructure scripts across multiple languages. It detects bugs, security vulnerabilities, and maintainability issues to ensure software meets reliability and security standards. The platform implements automated quality gates for continuous integration and delivery pipelines, verifying code against defined rules during merge or pull requests. It also integrates directly with code editors to provide real-time analysis results and quick-fix guidance during development. The system covers broad functional areas includin

Kiro is an AI-powered development tool and multi-agent workflow orchestrator. It functions as a context-aware code generator and coding assistant that transforms natural language requirements into structured implementation plans and production-grade code. The system distinguishes itself through multi-agent task decomposition, where complex requirements are broken into sequenced tasks and assigned to specialized agents. It features multi-model orchestration to select specific language models based on reasoning complexity, cost, and latency, and includes a headless command-line interface for id

my-git is a comprehensive framework and reference guide for Git version control administration, repository governance, and software release management. It provides a structured approach to managing the software development lifecycle, from initial feature branching to final production deployment. The project distinguishes itself through a specialized AI-assisted development framework. This includes workflows for managing AI-generated code via automated diff reviews, intent-based commit splitting, and governance models for multi-agent coordination and session isolation using worktrees. The cod

Combination of multiple linters to run as a GitHub Action or standalone

The Snyk CLI is a command-line security scanner that detects known vulnerabilities across open-source dependencies, proprietary application code, container images, and infrastructure-as-code configuration files. It also serves as a platform management tool, allowing users to configure organizations, users, SSO, and reporting from the terminal rather than the web dashboard. The CLI integrates directly into development workflows, enabling scanning within IDEs, build pipelines, and version control systems. It implements static analysis with interfile data flow analysis to find complex security f

Lychee is a command line link checker written in Rust that scans websites and local files to identify broken hyperlinks and invalid email addresses. It functions as an asynchronous link validator and static site auditor designed to ensure content accessibility and quality. The tool features disk-based response caching to accelerate subsequent scans and avoid redundant network requests. It supports token-based API authentication for services like GitHub to bypass rate limits when verifying links on remote repositories. The project covers a range of capabilities including multi-format content

ChatGPT-CodeReview is an AI-driven code analysis tool and bot that uses a large language model to automatically review pull request diffs and post feedback on code changes. It functions as a system for detecting bugs and suggesting improvements in source code. The tool provides a containerized runtime for deployment as a background process or through a GitHub Action. Users can customize the analysis behavior, style, and technical depth by adjusting model parameters and system prompts. The system handles automated code review workflows by triggering analysis via webhooks and CI pipelines, upd

webpack-bundle-analyzer is a bundle size analysis tool and Webpack build plugin that visualizes the composition of web application assets. It generates an interactive treemap to identify large dependencies and analyze the distribution of modules within the final payload. The tool functions as a bundle visualizer and a static report generator, exporting analysis data as standalone HTML and JSON files. It supports live bundle tracking via WebSockets during development and allows for the analysis of existing static stats files through a command line interface. The project provides capabilities

axe-core is an automated accessibility testing engine and compliance auditor designed to scan web and mobile interfaces for violations of industry accessibility standards. It functions as a programmatic scanner and linter that analyzes HTML and source code to identify barriers and verify compliance with accessibility guidelines. The project distinguishes itself by combining a DOM-based rule engine with computer vision and machine learning to detect complex violations that evade traditional analysis, such as visual heading discrepancies and informative images. It provides specialized capabilit

Datree is a policy enforcement framework for Kubernetes that validates configurations against rules written in Rego, JSON Schema, or CEL. It operates as both a command-line tool for pre-deployment scanning and as a cluster-side admission webhook for real-time enforcement, integrating with CI/CD pipelines and continuous delivery tools like ArgoCD and FluxCD. The framework supports namespace-scoped policy mapping, allowing different policies to apply to different namespaces, and provides a skip annotation mechanism for selectively bypassing rules on individual resources or entire namespaces. It

Strix is an automated security research and vulnerability scanning platform that leverages language models to orchestrate complex security analysis tasks. It functions as a comprehensive framework for penetration testing and continuous security integration, allowing users to embed automated vulnerability research directly into development pipelines or execute it within isolated, containerized environments. The platform distinguishes itself through a multi-agent orchestration engine that coordinates specialized autonomous agents to perform parallel security assessments. By integrating LLM-agno

X-ray is a headless browser web scraper and HTML content crawler designed to extract structured data from websites. It functions as a stream-based data scraper and structured data extractor, using selectors to retrieve text and attributes from HTML as nested objects or arrays. The project includes a request rate controller to manage network traffic through concurrency limits, throttles, and timeouts. It handles dynamic website scraping by rendering JavaScript via a headless browser and performs automated website crawling using breadth-first link following and pagination management. The syste

pydoll is a Chrome DevTools Protocol automation library and headless browser controller used for web data extraction and parallel browser automation. It controls Chromium-based browsers via direct WebSocket connections, allowing it to manage isolated browser contexts and tabs while bypassing the overhead and detection associated with WebDriver. The project features an anti-bot evasion framework that mimics natural human behavior, including mouse movements generated via Bezier curves and variable typing patterns. It provides specialized stealth capabilities to bypass behavioral analysis and au