Tools

Zero-config conversion of FastAPI endpoints into MCP tools

FastAPI-MCP automatically converts existing FastAPI endpoints into Model Context Protocol tools with zero configuration. With 11,700+ GitHub stars, it is the most popular MCP integration layer, enabling thousands of FastAPI developers to make their APIs accessible to AI agents like Cursor and Claude through the MCP standard.

No-code knowledge base platform with visual AI workflow and built-in RAG

FastGPT is an open-source no-code AI knowledge base platform with 27,000+ GitHub stars and 500,000+ users worldwide. It combines visual workflow orchestration, built-in RAG pipelines, QA-pair extraction, and API-aligned completions into a single deployable stack that runs on just 2GB RAM via Docker one-liner deployment.

Python web framework with HTMX, no JavaScript needed

FastHTML is an open-source Python web framework by Answer.AI that renders HTML directly from Python functions using HTMX. It eliminates the JavaScript build step entirely, letting developers create interactive web apps with pure Python. FastHTML is designed for AI demo apps, admin tools, and internal tooling where full-stack simplicity matters more than SPA complexity. Built by Jeremy Howard's team.

Open-source feature store for machine learning

Feast is an open-source feature store that manages and serves ML features for both training and online inference. It prevents training-serving skew by providing consistent feature access across offline and real-time environments. Feast supports batch materialization from data warehouses, real-time feature retrieval, on-demand transformations, and integrates with major data platforms including BigQuery, Snowflake, Redshift, and DynamoDB.

Generate SDKs and API documentation from OpenAPI specs

Fern is a platform that generates idiomatic client SDKs and beautiful API documentation from OpenAPI specifications. It produces type-safe SDKs for TypeScript, Python, Java, Go, Ruby, and C# with features like pagination, retries, and streaming built in. The documentation includes API reference, guides, and an AI-powered search assistant. Used by companies like Cohere, ElevenLabs, and Merge.

Open-source toolkit for curating datasets and evaluating visual AI models

FiftyOne is an open-source Python toolkit from Voxel51 for building high-quality datasets and better computer-vision and multimodal AI models. It pairs a browser-based visualization App with programmatic dataset curation, embeddings, similarity search, and model-evaluation workflows.

Security operations resilience for SOC teams

Fig provides a Security Operations Resilience platform designed for modern SOC teams facing both unplanned and planned changes. Features drift detection to catch unplanned infrastructure changes, automated drift repair with testing, planned change modeling to simulate initiatives before deployment, version control, and automatic deployment with rollbacks. Helps teams maintain security coverage while shipping risk-free at 10x speed and focusing on strategic cyber work.

Turn a Figma design system into a programmable API for AI assistants

Figma Console MCP is open-source design-system infrastructure that exposes Figma to AI assistants through MCP. It supports structured extraction, design creation and editing, debugging, accessibility audits, and bidirectional design-token workflows across local, remote read-only, and paired cloud modes; it is not a generic one-click Figma-to-code exporter.

Design-to-code handoff and CSS generation

Figma Dev Mode is a dedicated workspace within Figma designed specifically for developers to inspect designs, extract code snippets, and access implementation details without navigating the full design environment. It solves the design-to-development handoff problem by providing a focused, code-oriented view with measurements, component properties, design tokens, and ready-to-use code in CSS, iOS, and Android formats.

AI QA agent specialized for mobile apps

FinalRun is a specialized AI QA agent for mobile applications that automates testing of complex mobile gestures and flows on both iOS and Android platforms. It addresses the specific mobile QA gap that generic web-testing tools miss, handling touch interactions, swipe gestures, device rotation, and platform-specific behavior that require mobile-native understanding.

Unified multi-cloud cost management with MegaBill

Finout unifies cloud costs from AWS, Azure, GCP, Snowflake, and other providers into a single MegaBill dashboard with AI-based anomaly detection for flagging unusual spend patterns. Priced at approximately 1% of cloud spend, it solves the multi-tool cost fragmentation problem for organizations managing complex infrastructure budgets across multiple cloud and SaaS providers.

Google's AI-powered cloud IDE for full-stack app development

Firebase Studio is Google's cloud-based development environment that integrates Gemini AI for building, testing, and deploying full-stack applications. It provides browser-based coding with AI assistance for code generation, debugging, and database design. Connects natively with Firebase services including Firestore, Authentication, Cloud Functions, and Hosting for seamless deployment.

Open-source multi-protocol API client

Firecamp is an open-source API DevTool supporting REST, GraphQL, WebSocket, and Socket.IO protocols as a lightweight alternative to Postman. It provides IntelliSense, team collaboration with shared workspaces, and seamless import from OpenAPI, Insomnia, AsyncAPI, and HAR formats. Each protocol gets a dedicated testing playground with response metrics including time, size, and status codes.

Open-source microVMs for secure serverless and AI agent sandboxing

Firecracker is an open-source virtual machine monitor that creates lightweight microVMs with sub-150ms cold starts, originally built by AWS for Lambda and Fargate. With 28,000+ GitHub stars, it provides kernel-level isolation for running untrusted code safely and powers the sandboxing infrastructure behind AI coding agents like Devin and E2B.

Production-grade inference with serverless and on-demand GPUs

High-performance inference platform serving open-source and custom AI models at global scale, processing 13+ trillion tokens daily at ~180K requests per second. Fireworks AI delivers 1,000+ tokens per second on large models through quantization-aware tuning and adaptive speculation, with serverless, fine-tuning, and dedicated GPU options across text, image, and audio modalities.

The friendly interactive shell

User-friendly interactive shell for Linux and macOS that works great out of the box with zero configuration needed. Features autosuggestions based on command history (accept with right arrow), syntax highlighting as you type, tab completions with inline descriptions, web-based configuration UI for themes and settings, and a scripting syntax that is simpler than bash/zsh. Not POSIX-compatible by design. Popular among developers who want a productive shell without customization effort.

Multilingual emotional text-to-speech with 80+ language support

Fish Speech is an open-source text-to-speech system supporting 80+ languages with emotional expression, zero-shot voice cloning, and real-time streaming. It generates natural speech with controllable emotions, speaking styles, and prosody. Features a web interface, API server, and integration with AI agent frameworks for voice-enabled applications. Over 29,000 GitHub stars.

Open-source feature flags and remote configuration

Flagsmith is an open-source feature flag and remote config platform with 15+ SDKs, a clean REST API, and simple Docker deployment. It supports boolean, multivariate, and string flags with segment-based targeting, A/B testing via flag variations, and environment-based workflows. Flagsmith provides a straightforward self-hosted alternative to LaunchDarkly with full API-first design under a BSD-3-Clause license.

Fast memory-efficient GPU attention kernels

FlashAttention is a fast and memory-efficient exact attention implementation that reduces GPU memory usage from quadratic to linear in sequence length. Created by Tri Dao, it achieves 3-4x speedups over baseline implementations through IO-aware tiling that minimizes HBM reads and writes. Versions include FlashAttention-2 with improved parallelism, FlashAttention-3 optimized for Hopper H100 GPUs, and FlashAttention-4 targeting Hopper and Blackwell architectures.

Usage metering and billing infrastructure for AI, API, and SaaS products

Flexprice is an AGPL-3.0 open-source platform for real-time usage metering, usage-based pricing, credits, entitlements, and billing workflows. It helps engineering and finance teams turn token, API, and feature events into billable usage across managed-cloud or self-hosted deployments. Use it when a product needs finance-grade chargeback and customer usage controls, not only LLM traces.

Free open-source local AWS emulator as a drop-in LocalStack replacement

Floci is a free open-source AWS emulator designed as a lightweight drop-in replacement for LocalStack Community Edition. It runs on port 4566 with the same endpoint conventions, supporting S3, SQS, DynamoDB, RDS, ElastiCache, API Gateway, Cognito, IAM, and twenty-plus other services. The Docker image is ninety megabytes versus LocalStack's one gigabyte and starts in twenty-four milliseconds.

Visual workflow builder by ByteDance

FlowGram is an open-source visual workflow and flowchart editor framework developed by ByteDance for building node-based workflow applications. It provides a React-based canvas with drag-and-drop node creation, configurable edge routing, zoom and pan controls, and a plugin architecture for extending functionality. FlowGram supports both fixed layout and free-form canvas modes, making it suitable for building AI agent pipelines, data processing flows, and automation builders.

Continuous security scanning with AI and human expertise

Fluid Attacks integrates continuous vulnerability scanning into the SDLC by combining AI automation with human security expertise to verify critical flaws. The hybrid approach ensures that automated findings are validated by security researchers before reaching developers, reducing false positive noise while maintaining coverage across SAST, DAST, SCA, and infrastructure-as-code security scanning.

GitOps toolkit for Kubernetes — continuous delivery the cloud-native way.

Flux is a CNCF graduated GitOps tool for keeping Kubernetes clusters in sync with configuration sources like Git repositories, Helm charts, and OCI artifacts. Lightweight, composable, and designed to work with existing tools. The primary alternative to ArgoCD in the GitOps space.

Run your app close to users

Global application hosting platform that runs full-stack apps, databases, and services close to users in 30+ regions using lightweight Firecracker micro-VMs. Deploy Docker containers or use built-in builders for Rails, Laravel, Django, Node.js, and Go. Features persistent volumes, private networking, auto-scaling, PostgreSQL/Redis managed databases, and a powerful CLI. Ideal for latency-sensitive apps needing multi-region presence. Generous free allowance with pay-as-you-go pricing.

Blazing fast Solidity development toolkit

Foundry is a blazing-fast portable toolkit for Ethereum smart contract development written in Rust. It provides Forge for testing and deploying Solidity contracts with native Solidity tests that run orders of magnitude faster than JavaScript-based alternatives, Cast for interacting with EVM chains from the command line, Anvil as a local testnet node, and Chisel as a Solidity REPL. Foundry has become the standard toolchain for serious Solidity development.

Free and open-source Kubernetes IDE for managing clusters visually

Freelens is a free open-source Kubernetes IDE that provides a visual desktop interface for managing clusters, workloads, and configurations. Forked from the original Lens project after its licensing change, Freelens offers the same powerful cluster management experience with real-time monitoring, log viewing, and resource editing under the MIT license.

Beautiful docs for Next.js App Router

Fumadocs is a documentation framework built specifically for Next.js that provides a complete set of tools for creating high-performance documentation sites within the Next.js App Router. Offers tight integration with server components, middleware, and API routes, plus headless UI primitives, MDX processing, built-in search, and flexible theming — giving teams full control over their docs' look and feel.

Builder.io visual canvas with Figma-to-code and code-to-Figma sync

Fusion by Builder.io is a visual development canvas that provides bidirectional sync between Figma designs and production code. Designers edit in Figma while developers work in code, and changes propagate in both directions. Supports React, Vue, Svelte, Angular, and Qwik output with a visual editor for non-developers to make content and layout changes without touching code.

Self-hosted customer identity management with no per-user pricing

FusionAuth is a customer identity and access management platform that can be self-hosted or cloud-deployed with no per-user fees. It supports OAuth2, OIDC, SAML, passwordless login, social providers, MFA, and advanced threat detection. Features a drag-and-drop theme builder for login page customization and supports multi-tenant application architectures with unlimited users on the community edition.

AI-powered resilient mobile test flows

GPT Driver is a mobile app QA tool that uses generative AI to create resilient test flows with self-healing capabilities and broad framework support for cross-platform applications. It leverages AI to handle the non-deterministic nature of mobile UI where elements shift between releases, generating tests that adapt to layout changes rather than breaking on every app update.

Open-source voice cloning and text-to-speech with few-shot learning

GPT-SoVITS is an open-source voice cloning and text-to-speech system that generates natural-sounding speech from just a few seconds of reference audio. It combines GPT-style language modeling with SoVITS voice synthesis for zero-shot and few-shot voice cloning across multiple languages. Supports Chinese, English, Japanese, Korean, and Cantonese with over 56,000 GitHub stars.

Natural language scripting for LLM-system interaction

GPTScript is an Apache 2.0 licensed framework with 3,300+ GitHub stars that enables natural language scripting where LLMs interact with local systems, APIs, and tools through simple prompt definitions. It supports multiple model providers including OpenAI-compatible APIs and local models, providing a lightweight approach to building AI agents that can execute CLI commands, call APIs, and process files.

Open-source GPU control plane for scalable AI model serving

Open-source GPU cluster manager that configures vLLM, SGLang, TensorRT-LLM or custom engines, serves models through compatible APIs, and provisions SSH-accessible GPU instances across on-premises, Kubernetes and cloud environments.

Graph-relational database with EdgeQL query language, formerly EdgeDB

Gel (formerly EdgeDB) is a graph-relational database that combines the relational model with graph database traversal capabilities through its EdgeQL query language. Built on PostgreSQL, it eliminates the object-relational impedance mismatch with a type system that maps directly to application data models. Features built-in migrations, authentication, and an interactive web UI.

Meta-prompting and context engineering system for Claude Code agents

GSD is a meta-prompting, context engineering, and spec-driven development system designed for Claude Code and compatible AI coding agents. With over 46,000 GitHub stars, it implements a structured four-phase workflow of Discuss, Plan, Execute, and Verify to combat context rot in long AI coding sessions. The system uses multi-agent orchestration with persistent file-based memory.

MCP server for AI-powered reverse engineering

GhidraMCP is an MCP server that enables LLMs to autonomously perform reverse engineering tasks through NSA's Ghidra disassembly framework. It exposes binary analysis capabilities like decompilation, function listing, cross-references, and symbol analysis as MCP tools, letting AI assistants generate malware reports and analyze compiled binaries.

Codeless browser testing with visual test recorder and scheduling

Ghost Inspector provides codeless browser testing through a visual recorder that captures user interactions and converts them into automated test suites. Tests run on managed infrastructure with scheduled execution, CI/CD integration, and Slack notifications. Features visual comparison for UI regression detection, API testing, and test organization with folders and tags for managing large test suites.

Bayesian git bisection for finding commits that caused flaky tests

Git Bayesect applies Bayesian inference to git bisection, solving the problem of finding commits that introduced non-deterministic bugs like flaky tests. Unlike standard git bisect which requires binary pass-fail results, Git Bayesect handles probabilistic outcomes where a test might pass sometimes and fail sometimes, using entropy minimization to efficiently narrow down the culprit commit.

Knowledge management for teams

Modern documentation platform that combines a WYSIWYG editor with Git-backed version control for technical documentation, API references, and knowledge bases. Features real-time collaboration, OpenAPI/Swagger integration for auto-generated API docs, custom domains, visitor authentication, and AI-powered search. Syncs bidirectionally with GitHub/GitLab repositories. Includes analytics for tracking documentation usage. Used by Ethereum, Linux Foundation, and thousands of developer teams.

Run AI coding agents in GitHub Actions from Markdown

Open-source GitHub CLI extension for defining repository automations in Markdown and running Copilot, Claude Code, Codex, Gemini or custom agents inside hardened GitHub Actions workflows.

Built-in project planning for GitHub

GitHub's built-in project management tool that organizes issues, pull requests, and draft items into customizable boards, tables, and roadmap views directly within your repositories. Features custom fields, automated workflows for moving items based on PR/issue status, grouping, filtering, milestones, and iteration planning. Integrated with GitHub Issues and PRs for seamless developer workflows. Free for all GitHub users. A lightweight alternative to Jira for GitHub-centric teams.

Visual Git client with built-in collaboration

GitKraken is a cross-platform visual Git client providing an intuitive graph visualization of repository history, branches, and merges. Features include drag-and-drop branch management, interactive rebase, merge conflict editor, built-in code editor, GitFlow support, and integrations with GitHub, GitLab, Bitbucket, and Azure DevOps. Includes GitLens for VS Code providing inline blame annotations, code authorship, and commit history. Free for public repos, paid for private repositories.

Built-in CI/CD for GitLab

GitLab's built-in CI/CD pipeline system defined via .gitlab-ci.yml files in your repository. Features multi-stage pipelines, parallel jobs, matrix builds, environments with deployment tracking, merge train for serialized merges, auto DevOps for zero-config CI/CD, container registry, and security scanning (SAST/DAST). Supports self-hosted runners and Kubernetes executors. Tightly integrated with GitLab's merge requests and issue tracking. A leading alternative to GitHub Actions for GitLab users.

Most popular VS Code Git extension with 30M+ installs

GitLens is the most-installed Git extension for VS Code with over 30 million installs. It supercharges Git inside the editor with inline blame annotations, rich commit history visualization, file and line history, AI-powered commit summaries, and interactive rebase tools. Pro features include GitKraken-powered team analytics and visual diff tools. Maintained by GitKraken.

Instant MCP server for any GitHub repository

GitMCP is a free, open-source remote MCP server that transforms any GitHub repository or GitHub Pages site into an AI-accessible documentation hub. Just replace github.com with gitmcp.io in any repo URL to give AI assistants grounded context about that project — eliminating code hallucinations with zero configuration required.

Pull Requests as a Service with AI + developers

GitStart is a YC-backed platform that delivers merge-ready pull requests by combining AI coding agents with human developer oversight. Teams assign sprint-sized tickets and the AI Ticket Studio converts vague requirements into well-scoped specs, then hybrid agents generate production-ready code through a five-stage quality process with a 98% merge rate reported across customer teams.

MCP server directory and gateway

AI gateway and model management platform that provides a unified API for accessing multiple LLM providers (OpenAI, Anthropic, Google, Mistral, and more) through a single endpoint. Features model routing, cost tracking, usage analytics, rate limiting, and API key management across providers. Simplifies multi-provider AI integration by handling authentication, billing, and failover in one place. Useful for teams evaluating multiple models or building provider-agnostic AI applications.