1,322 Developer Tools (2026)

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.

Google's beta command-line tool that lets coding agents and scripts call Gemini models, media generation and managed agents

Gemini API CLI (gemini-api) is Google's Apache-2.0, beta command-line tool for the Gemini Interactions API. One stateless Go binary lets Claude Code, Codex, Antigravity and other shell-capable agents generate text, images, speech, music and video, analyze PDFs, media and YouTube URLs, transcribe recordings, and launch background managed agents such as Deep Research. It offers --dry-run previews, JSON or TOON output and an agent mode. It is not a coding agent.

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.

Agent Development Kit by Google

Google's open-source framework for building AI agents with Gemini models. Supports multi-agent orchestration, tool use, and deployment to Vertex AI or Cloud Run. Provides a structured approach to agent development with built-in evaluation, testing, and monitoring capabilities, making it the official path for teams building agent systems within the Google Cloud ecosystem.

Run open-source LLMs on your phone, fully offline and private

Google AI Edge Gallery is an open-source mobile app that lets you download and run large language models like Gemma directly on Android and iOS devices with zero cloud dependency. Built on MediaPipe and LiteRT, it features AI chat with reasoning mode, multimodal image analysis, real-time audio transcription, and autonomous agent skills—all running entirely on-device for complete privacy. A reference implementation for developers building offline-first AI experiences.

Free MCP tools and Google-authored skills that connect coding agents to BigQuery and other Google Data Cloud services

Google Cloud Data Agent Kit is a free set of MCP tools and open-source agent skills that lets coding agents such as Claude Code, Codex, Cursor and Antigravity work with live Google Data Cloud resources. Agents can inspect schemas, run queries, read job logs and build pipelines across 15+ services such as BigQuery, Spanner, AlloyDB and Bigtable, using your own IAM permissions. It ships as an IDE extension and agent plugins and has been GA since September 2026.

Google Cloud ML platform with Gemini and custom models

Google Cloud's end-to-end ML platform with Gemini models, Model Garden featuring 150+ models, AutoML, and custom training pipelines. Features Vertex AI Search, Conversation, and Agent Builder for enterprise AI applications. The comprehensive platform for organizations building production AI systems at scale within the Google Cloud ecosystem, with enterprise governance and compliance built in.

First-party MCP server for querying and managing Grafana

Grafana's official Model Context Protocol server, letting AI assistants search dashboards, query datasources, and manage alerts/incidents on your Grafana instance through a standard MCP interface.

Turn code and docs into a queryable knowledge graph

Graphify is an open-source AI coding assistant skill that transforms folders of code, documentation, research papers, and images into queryable knowledge graphs. It works as a skill for Claude Code, Codex, OpenCode, and other AI coding assistants. Using tree-sitter AST parsing for 19 programming languages and Claude vision for documents and images, it builds NetworkX graphs with Leiden community detection, outputting interactive HTML visualizations and structured JSON for codebase exploration.

Build real-time temporal knowledge graphs for AI agents

Graphiti is an open-source Python framework by Zep for building temporally-aware knowledge graphs for AI agents. It continuously integrates conversations, business data, and external information into queryable graphs with bi-temporal tracking. The hybrid retrieval combines semantic search, BM25 keywords, and graph traversal for sub-300ms queries without LLM calls at retrieval time.

Data quality validation framework for Python

Great Expectations is an open-source Python framework for validating, documenting, and profiling data quality. Teams define expectations as expressive unit tests for their data using an intuitive API, then validate datasets against those rules in CI/CD pipelines or production workflows. It connects to pandas, Spark, and SQL sources, generates data documentation automatically, and integrates with orchestrators like Airflow and Prefect for continuous data quality monitoring.

Synthetic data generation platform for privacy and ML

Gretel is a synthetic data platform that generates realistic, privacy-preserving datasets for ML training, testing, and data sharing. It supports tabular, text, and time-series data with configurable privacy guarantees including differential privacy. Features include data augmentation for imbalanced datasets, PII detection and anonymization, and API/SDK access for pipeline integration with BigQuery, Snowflake, and Databricks.

Modular AI agent framework with off-prompt data

Griptape is an open-source Python framework for building AI agents and workflows with a focus on modularity and enterprise-grade off-prompt data handling. It separates predictable pipeline logic from unpredictable LLM interactions, providing structures for sequential and parallel task execution with built-in memory management and tool integration.

Turn code repositories into source-grounded wikis and docs

Desktop workspace that transforms local and remote git repositories into source-grounded wikis, architecture documents, and interactive Ask sessions. Integrates directly with existing CLI agents including Grok CLI, Claude Code, and Codex without requiring proprietary cloud infrastructure. Generates verifiable file citations, Mermaid diagrams, and Obsidian-compatible exports while ensuring private codebase data remains strictly on the local machine.

Production-grade Terraform modules and infrastructure library

Gruntwork provides a library of battle-tested, production-grade Terraform modules covering AWS, GCP, and Azure infrastructure patterns. Modules handle networking, compute, databases, security, monitoring, and compliance with best practices built in. Terragrunt, their open-source Terraform wrapper with 15k+ stars, adds DRY configuration, remote state management, and multi-account orchestration.

Validate and structure LLM outputs with composable Guards

Guardrails AI is an open-source Python and JavaScript framework for validating and structuring LLM outputs using composable Guards built from a Hub of pre-built validators. It handles structured data extraction with Pydantic models, content safety checks including toxicity, PII detection, competitor mentions, and bias filtering, plus automatic re-prompting when validation fails. The Guardrails Hub offers dozens of validators from regex matching to hallucination detection via LLM judges.

Constrained generation that guarantees valid LLM outputs every time

Guidance is Microsoft's structured generation library that enforces output constraints directly within LLM decoding. It supports JSON schemas, regex patterns, grammars, and interleaved generation-and-control flow to guarantee valid outputs from any compatible model. Works with local models via llama.cpp, Transformers, and remote APIs including OpenAI and Anthropic. Eliminates retry loops and post-processing for structured data extraction.

Human-friendly HTTP client

User-friendly CLI HTTP client for testing and debugging APIs with intuitive syntax, colorized output, and JSON highlighting. Simpler than curl with sensible defaults — auto JSON formatting, persistent sessions, and auth helpers. Also available as HTTPie Desktop (GUI) and HTTPie for Web (browser-based). Supports HTTPS, proxies, file uploads, and plugins. 34K+ GitHub stars. The developer-friendly curl alternative for API work.