PiG

Open source alternative to Claude Code

657 stars
MIT
Active this week
Last commit 2 days ago

Last verified Oct 20, 2026

Run Pi's terminal coding agent from a single Go binary, with no Node.js needed, 15+ AI providers, and a Go/Rust/Python extension system.

Visit website GitHub657

Read the full breakdownWho it is for, how it works, trade-offs, the quick start and the FAQ

who it's for

Who PiG is for#

Go developers building or embedding a coding agent

PiG exposes a public Go SDK with `agent` and `coding` packages. Go developers can embed the agent loop in their own applications, write extensions in Go, or use `go install` for a zero-dependency install path that fits naturally into a Go-first environment.

Skip if:

Your team works exclusively in TypeScript or Python and has no Go codebase. The Go SDK is the differentiating value here; if you do not need it, the upstream Pi or Claude Code is a simpler starting point.

Teams on resource-constrained or Node-free servers

PiG's single binary runs on Linux with no Node.js, no npm, and no runtime installation. This makes it practical on minimal VMs, CI runners, and containers where keeping the dependency footprint small matters.

Skip if:

You already have Node.js installed and your team does not maintain lean Linux environments. The Node.js dependency is not a real friction point in that context.

Extension authors writing Go or Rust extensions

Pi's extension ecosystem is TypeScript-only. PiG adds Go, Rust, and Python extension SDKs, so teams who prefer compiled languages can write and distribute PiG extensions without a TypeScript toolchain.

Skip if:

Your extension needs are already covered by TypeScript. PiG passes Pi's TypeScript extension API through unchanged, so existing Pi extensions run on PiG without modification.

Platform teams building custom agent pipelines

The RPC mode (JSON over stdin/stdout) and the Go SDK make PiG composable in larger pipelines. Piglets let you assemble named agent configurations from extensions, skills, and prompts, then distribute them as standalone binaries or share them as YAML definitions.

Skip if:

You need a fully managed, subscription-based coding assistant with no infrastructure ownership. PiG requires you to manage your own API keys and optionally your own server.

the problem

The problem it solves#

Terminal coding agents like Claude Code tie developers to a single vendor's API and require a Node.js runtime to run locally. For teams on Go-first infrastructure, minimal Linux servers, or CI environments, adding Node.js as a system dependency introduces friction, creating version conflicts, startup overhead, and an extra runtime to install and patch on every machine.

The deeper pain is provider lock-in. When a vendor changes pricing, deprecates a model, or experiences an outage, teams with a single-provider agent have no local fallback. Running multiple agents to cover different providers means learning different tool interfaces and maintaining separate configuration files.

how PiG solves it

How it solves it#

Single Go binary, no Node.js runtime

PiG compiles to one statically-linked `pig` executable for macOS, Linux, and Windows. There is no Node.js runtime requirement. The binary is available via curl, npm (as a platform-specific optional dependency), PowerShell, `go install`, or a GitHub Releases download. Startup is native Go speed.

15+ AI providers with mid-session model switching

PiG ships with built-in support for Anthropic, OpenAI, Google, Azure, Bedrock, Mistral, Groq, Cerebras, xAI, Ollama, and more. Switch models mid-session with `/model` or cycle through scoped models with Ctrl+P. API key and OAuth authentication both work.

Go, Rust, Python, and Node extension system

Extensions register tools, commands, event handlers, flags, providers, and UI contributions through a public Go API. Node extensions use Pi's TypeScript extension API unchanged. Bundle extensions, skills, and prompts into a named Piglet for a shareable agent application, or build one as its own executable.

Tree-structured sessions with branching

Sessions are stored as trees. `/tree` lets you navigate to any previous turn and branch from there; all branches live in one file. Filter by message type, bookmark entries, export to HTML with `/export`, or share a branch as a GitHub gist with `/share`.

Four execution modes: TUI, print, RPC, and Go SDK

Run PiG as an interactive TUI, use print or JSON mode for one-shot scripts, connect over an RPC protocol (JSON over stdin/stdout) for process-based integrations, or embed the agent in Go applications through the Go SDK.

strengths · trade-offs

Strengths and trade-offs#

Strengths

MIT license with provider freedomPiG is MIT licensed, so you can run it commercially, modify it, and embed it in Go applications without licensing restrictions. Unlike Claude Code, which is tied to Anthropic's API, PiG works with any of its 15+ supported providers, including a local Ollama instance for fully offline or air-gapped use.
Upstream Pi parity with verified evidencePiG does not rewrite Pi's behavior; it ports and verifies the port. Core paths are checked against Pi 0.87.1 with paired parity scenarios. Every intentional divergence is documented in `DIVERGENCES.md`. Projects and extensions that work on Pi carry over with no rework.
Go SDK for embedding in applicationsPiG's public `coding` and `agent` packages let you embed the agent loop, extension contracts, and Piglet composition into your own Go applications. Terminal-only coding agents have no embeddable library path; PiG is also a library.
OpenSSF-graded supply-chain practicesThe project carries OpenSSF Scorecard and OpenSSF Best Practices badges, passes CodeQL security analysis, is REUSE-compliant for license attribution, and ships artifact-specific SBOMs with each release. The install script verifies each download against SHA256 checksums before installing.

Trade-offs

-Pre-stable 0.x with edge cases still hardeningPiG is a 0.x release. The README states: "Core paths are ported and checked against Pi 0.87.1 with paired parity scenarios; edge cases are still hardening." For teams that need production-grade stability today, the upstream Pi or a managed coding agent service is a lower-risk choice.
-Windows support is a previewPiG's Windows release is labeled a preview. The repository states: "Do not treat a platform as release-supported until its native release verification passes." Windows users may encounter behavioral gaps not present on macOS or Linux.
-Parity scope excludes some Pi packagesPiG does not implement Pi's experimental remote Session packages or standalone telemetry and evaluation packages. If your workflow depends on those Pi features, PiG does not yet cover them.

versus alternatives

PiG vs alternatives#

PiG vs Claude Code

Both PiG and Claude Code are terminal coding agents that read project files, run shell commands, and work alongside developers through a conversation loop. The primary decision criterion is whether you need a proprietary managed tool or a self-owned, provider-agnostic binary.

Feature	PiG	Claude Code
License	MIT	Proprietary
Provider support	15+ providers	Anthropic only
Runtime	Single Go binary, no Node.js	Requires Node.js
Self-hosting	Binary runs locally, no server	Managed by Anthropic
Extensions	Go, Rust, Python, Node	TypeScript/JavaScript
Go SDK	Yes	No
Release stability	Pre-stable 0.x	Stable

PiG is the stronger choice when your team needs provider flexibility. Switch between Anthropic, OpenAI, a local Ollama instance, or any of the 15+ supported providers with /model, all without changing tools. For Go-first teams, the Go SDK and native extension contracts let you write tools, commands, and agent compositions in Go without a TypeScript toolchain.

Claude Code is the better choice for teams that want a stable, polished product with official support. It is also a lower-friction starting point for Windows users: PiG's Windows support is a preview, while Claude Code is release-grade on all platforms. PiG's 0.x status means edge cases are still hardening; for teams where a coding agent is critical infrastructure, Claude Code's maturity is a real advantage today.

install · quick start

Quick start#

bash

Install PiG as a single native binary using the platform install script, npm, or Go.

```bash
# macOS / Linux
curl -fsSL https://pi-in-go.dev/install.sh | sh

# npm (any platform)
npm install -g @pi-in-go/pig

# Go
go install github.com/MichaelKinsy/PiG/cmd/pig@latest
```

tech stack · detected from GitHub

What it's built on#

Languages: GoJavaScriptPythonRustTypeScript

frequently asked

FAQ#

Is PiG compatible with Claude Code extensions or Pi extensions?

PiG does not run Claude Code extensions. It does run Pi's TypeScript extensions unchanged, because PiG ships compatible runtime modules for Pi's TypeScript extension API. If you have existing Pi extensions, they work on PiG without modification. PiG also supports native Go, Rust, and Python extensions through its own extension SDK.

Does PiG require an Anthropic API key?

No. PiG supports 15+ providers including OpenAI, Google, Azure, Mistral, Groq, and a local Ollama instance. You provide API keys for the providers you choose. Run /login on first launch to configure a provider; no specific key is required to install the binary.

Is PiG ready for production use?

PiG is a pre-stable 0.x release. Core agent paths are ported and verified against Pi 0.87.1, but the README notes edge cases are still hardening. It is suitable for development and exploration today; teams with strict reliability requirements should review the port status at test/parity/coverage.md before committing to production use.

Can I run PiG on an air-gapped machine?

Yes, with a local model provider. PiG supports Ollama, which runs models locally. Configure an Ollama endpoint as your provider and PiG routes requests to it with no external API calls. The binary itself is statically compiled and requires no internet connection after install.

What is the relationship between PiG and upstream Pi?

Pi is the reference implementation and remains the authoritative project. PiG follows Pi's behavior and design, tracking the pinned Pi 0.87.1 release. The PiG maintainers do not speak for the Pi project, and the Pi maintainers do not endorse PiG. If PiG behaves differently from Pi, that is either a bug or a documented intentional divergence.

Looking for more

Other ways to replace Claude Code#

OpenCode

#1 in the Claude Code guide

Broad provider and model choice in a terminal-first client, MIT-licensed with AGENTS.md instructions

218,637

oh-my-pi

#2 in the Claude Code guide

Direct Claude configuration inheritance with Anthropic subscription support

36,029

kilocode

#3 in the Claude Code guide

Documented Claude transcript import with IDE and CLI surfaces

27,673

Goose

#4 in the Claude Code guide

ACP subscription bridge that reuses an existing Claude Code or ChatGPT subscription

55,465

All 22 Claude Code alternatives 10 open source Claude Code alternatives, ranked

by category

Open source tools in these categories#

461

4,904 GitHub stars
Licence Apache-2.0
#AI Agents

Inbox Zero

Alternative toSuperhuman

AI email assistant that drafts replies and clears your inbox

12,712 GitHub stars
Licence AGPL-3.0
#Email

Omnara

Alternative toClaude Managed Agents

Open-source agent deployment API. Self-host or use Omnara Cloud.

2,957 GitHub stars
Licence Apache-2.0
#AI Agents

Feature your project

The projects we add and every new guide. Free, unsubscribe any time.

Find open source alternatives to paid software

PiG vs Claude Code

Feature	PiG	Claude Code
License	MIT	Proprietary
Provider support	15+ providers	Anthropic only
Runtime	Single Go binary, no Node.js	Requires Node.js
Self-hosting	Binary runs locally, no server	Managed by Anthropic
Extensions	Go, Rust, Python, Node	TypeScript/JavaScript
Go SDK	Yes	No
Release stability	Pre-stable 0.x	Stable

Who PiG is for#

Go developers building or embedding a coding agent

Skip if:

Teams on resource-constrained or Node-free servers

Skip if:

Extension authors writing Go or Rust extensions

Skip if:

Platform teams building custom agent pipelines

Skip if:

The problem it solves#

How it solves it#

Single Go binary, no Node.js runtime

15+ AI providers with mid-session model switching

Go, Rust, Python, and Node extension system

Tree-structured sessions with branching

Four execution modes: TUI, print, RPC, and Go SDK

Strengths and trade-offs#

Strengths

Trade-offs

PiG vs alternatives#

PiG vs Claude Code

Quick start#

What it's built on#

FAQ#

Other ways to replace Claude Code#

Open source tools in these categories#

Developer Tools

AI & Machine Learning

Backend Development

Find open source alternatives to paid software

Who PiG is for#

Go developers building or embedding a coding agent

Skip if:

Teams on resource-constrained or Node-free servers

Skip if:

Extension authors writing Go or Rust extensions

Skip if:

Platform teams building custom agent pipelines

Skip if:

The problem it solves#

How it solves it#

Single Go binary, no Node.js runtime

15+ AI providers with mid-session model switching

Go, Rust, Python, and Node extension system

Tree-structured sessions with branching

Four execution modes: TUI, print, RPC, and Go SDK

Strengths and trade-offs#

Strengths

Trade-offs

PiG vs alternatives#

PiG vs Claude Code

Quick start#

What it's built on#

FAQ#

Other ways to replace Claude Code#

Open source tools in these categories#

Developer Tools

AI & Machine Learning

Backend Development

Find open source alternatives to paid software