Xian Documentation

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What is Xian? ​

Xian is a Python-authored platform for programmable decentralized systems. It combines a deterministic contract language, a node/runtime stack, SDKs, operator tooling, optional indexed services, and shielded execution building blocks into one ecosystem.

The important framing is that Xian is not only "a smart-contract language." It is the full path from contract authoring to node operations to application integration.

What You Build With It ​

With Xian you can build:

  • public smart-contract applications such as tokens, registries, DEX flows, and workflow backends
  • application-specific networks and validator-operated decentralized services
  • backend services, wallets, agents, and automations that interact with those contracts through Python and TypeScript SDKs
  • shielded asset and shielded-command flows built on the runtime zk verifier, zk_registry, and the xian-zk proving toolkit

What Makes Xian Different ​

Python Authorship ​

Contracts are written in a restricted, deterministic Python subset. That keeps contract code readable for normal software teams while still enforcing sandboxing, metering, and deterministic state transitions.

Explicit Runtime Choices ​

Python is the source language, not the only execution engine. A network can run contracts through the tracer-based Python runtimes or through xian_vm_v1, which executes validated Xian VM artifacts under an explicit execution policy.

Full Operator Stack ​

The maintained repos cover the operator path end to end:

  • xian-cli for network and node workflows
  • xian-stack for Docker topology, localnet, monitoring, and sidecars
  • xian-abci for the deterministic application behind CometBFT
  • xian-configs for canonical network bundles and contract presets

Software-Friendly Integration ​

Xian ships the surfaces application teams usually need in practice:

  • xian-py and xian-js
  • browser and mobile wallets
  • dashboard REST and WebSocket feeds
  • BDS-backed indexed reads and optional GraphQL
  • a contract hub, playground, MCP server, and proving toolkit

Public and Shielded Execution ​

Xian supports both ordinary public contract flows and proof-backed shielded flows.

The shielded stack is split on purpose:

  • the runtime exposes a narrow native zk verifier surface
  • zk_registry stores active verifying keys
  • xian-zk handles proving, wallet sync, bundle generation, and local prover services off-chain
  • shielded-note-token, shielded-commands, and adapters implement the on-chain application layer

This lets Xian support privacy-sensitive flows without turning the validator runtime into a general-purpose proving environment.

Start Here ​