Build With Claude vs fx: Features, Pricing & Which Is Better (2026)
A side-by-side comparison of Build With Claude and fx — features, pricing, and ideal use cases — to help you decide which AI tool fits your workflow.
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Build With Claude
Dave Poon
A plugin marketplace and discovery hub for Claude Code to browse, install, and contribute agents, commands, hooks, skills, and plugin collections.
Key features
- Plugin Marketplace & Discovery: A web UI and index where users can browse curated plugins, agents, commands, hooks, skills, and bundled plugin collections for Claude Code.
- Community Indexing: Aggregates and indexes thousands of community resources (reported repository metrics include 20k+ community plugins, 4,500+ MCP servers, and 1,100+ external marketplaces) to surface third-party integrations and reusable components.
- Plugin Format & Validation: Defines standardized formats for Agents, Commands, and Hooks and provides contributing guidelines and npm test-based validation to ensure plugins meet repository conventions.
- Hooks & Event Automation: Supports hooks that run automatically on events (e.g., PreToolUse, PostToolUse, session start, tool calls) to enable event-driven automation like notifications, git operations, or formatting.
- Curated Collections & Packaging: Maintains curated collections and bundled plugin packages by category to help teams adopt opinionated stacks of agents and skills quickly.
- Integration with Claude Ecosystem: Designed to extend Claude Code, Claude Desktop, the Agent SDK, and OpenClaw, enabling seamless installation and use across developer surfaces.
- Web UI and CLI Workflow Support: Offers a web UI at buildwithclaude.com for discovery and documentation, plus repository-supplied assets and quickstart guidance for installing and using plugins within Claude Code workflows.
- Browse and search curated collections of Agents, Commands, Hooks, Skills, and Plugins via web UI (buildwithclaude.com)
- Repository of bundled plugin packages and community-discovered plugins with metadata and README documentation
- Support for plugin formats (agents, commands, hooks) with contribution guidelines and validation tests
- Integration references and documentation links for Claude Code, Agent SDK, Claude Desktop, and OpenClaw
- Indexes large external ecosystem: 20k+ community plugins, 4,500+ MCP servers, 1,100+ plugin marketplaces (community-sourced counts)
- Hooks system: event-driven automation for events like tool calls and session start
- CLI/Web/UI workflows: quickstart snippets, install instructions, and examples for using marketplace plugins
- Repository contains CI workflows, Dockerfile, tests, and web-ui source for building and deploying the marketplace
- Open-source MIT license enabling free use and community contributions
- Contributor tooling and build steps (bun, tauri, Rust, Cargo) and platform build guidance included in related repos
Best for
- Extending Claude Code Workflows: Install agent plugins and commands to automate common development tasks like generating commits, creating documentation, or running tests from within Claude Code.
- Assembling Specialized Agents: Combine curated agent skills (e.g., Python, DevOps, Security) to create domain-specific experts for code reviews, vulnerability scanning, or automated refactoring.
- Event-Driven Automation: Use hooks to trigger workflows on session start or tool calls—e.g., auto-formatting code, posting notifications, or syncing changes to issue trackers.
- Team Marketplaces and Collections: Create and share bundled plugin collections for a team or organization to standardize agent capabilities and onboarding.
- Discovering Community Integrations: Search the aggregated index to find plugins that add tool integrations (databases, APIs, CLIs) or MCP servers to enrich agent context and capabilities.
- Contribute and Publish Plugins: Follow repository contributing guidelines to add new agents, commands, or hooks, validate them with provided tests, and publish them to the community marketplace.
- Discover and install Claude Code agents to extend coding assistants for domain-specific workflows (DevOps, Security, Language-specific experts)
- Add slash commands and automation (e.g., /commit, /docs, /tdd) to streamline developer tasks
- Create and attach hooks for event-driven integrations (notifications, git operations, formatting) in Claude sessions
- Aggregate and reuse skills across projects to share capabilities between agents and workflows
- Integrate marketplace plugins into CI/CD pipelines, IDEs (VS Code, JetBrains), and terminals for automated code tasks
- Serve as a community index for integrating external MCP servers and marketplace collections into Claude ecosystems
fx
Vercel Labs
Vercel Labs' tiny open-source coding agent — a ~6 MB native CLI written in Zig, built for speed, embeddability and Unix-style ergonomics.
Key features
- Tiny Native Binary: The whole agent ships as a roughly 6 MB executable designed for instant installation and for embedding in resource-constrained environments and agent sandboxes.
- Instant Time to Prompt: fx cold starts in about 10 microseconds and performs no unnecessary work or I/O before accepting user input, which matters for programmatic invocation.
- Minimal Memory Footprint: A single-digit-megabyte memory baseline lets you pack many concurrent instances onto one machine.
- Shell-Like Ergonomics: Scroll history is preserved by default and output is deliberately sparse, so the CLI composes like a Unix tool instead of taking over the terminal.
- Context Efficiency: A minimal system prompt and tool surface reduce token spend and improve time-to-first-token performance.
- WebAssembly Builds: Optimal fx.wasm builds from the Zig toolchain shrink the binary further and make the network stack pluggable, enabling the in-browser demo.
- Model and Provider Agnostic: Works with local models, LLM gateways, direct provider API access or existing subscriptions rather than locking you to one vendor.
- Extensible Small Core: Capabilities are added through skills, plugins and MCPs, following a Unix-like philosophy of a small core with composable extensions.
Best for
- Sandboxed Agent Execution: Ship a full coding agent inside a container or sandbox where a large runtime would not fit.
- Embedding in Larger Systems: Use fx as the agent harness inside your own product or internal platform rather than building a loop from scratch.
- CI and Scripted Automation: Invoke a coding agent from pipelines and scripts where fast cold starts and quiet output matter more than an interactive UI.
- Agent Harness Research: Experiment with system prompt and tool design on a deliberately minimal, readable Apache-2.0 codebase.
- Local-Model Coding: Run agentic coding against a locally hosted model without any dependency on a specific cloud provider.
- Browser-Based Demos and Playgrounds: Compile to WebAssembly and run the agent client-side with networking delegated to browser fetch.