> For the complete documentation index, see [llms.txt](https://docs.coti.io/coti-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.coti.io/coti-documentation/privacy-on-avalanche.md).

# Privacy on Avalanche

**Privacy on Avalanche** applies Privacy on Demand to **Avalanche Fuji C-Chain** (chain ID `43113`): keep wallets, assets, and dApp contracts on Avalanche, and send **encrypted private computation** to **COTI Testnet**.

Fees on the host side are paid in **AVAX**. Private execution still happens on COTI; results return as ciphertext to your Fuji contracts for client-side decryption.

> **Development status:** This Privacy on Avalanche material and the **COTI PoD SDK** it describes are **under active development**. Treat them accordingly: on-chain and client code **may not yet be fully audited**, and **breaking changes** (APIs, ABIs, addresses, presets, or documentation) can occur as the stack matures. Pin versions, follow release notes, and perform your own review before relying on anything in production.

## Quick Access

* [**Getting started on Avalanche Fuji (Day 0)**](/coti-documentation/privacy-on-avalanche/getting-started-fuji.md) — Wallet, faucet, Hardhat/Foundry, SnowScan smoke-test.
* [**Tutorials: PoD dApps on Avalanche (choose your integration model)**](/coti-documentation/privacy-on-avalanche/tutorials-privacy-on-avalanche.md) — Primitive-only vs custom COTI logic, then links to step-by-step Fuji guides.
* [**Architecture and design**](/coti-documentation/privacy-on-avalanche/architecture-and-components.md) — Inbox, MPC executor, PodUser, PodLib, and how they connect.
* [**Avalanche Fuji network & addresses**](/coti-documentation/privacy-on-avalanche/networks/fuji.md) — Fuji C-Chain RPC, SnowScan, Inbox, Privacy Portal, and sample MpcAdder.
* [**Networks**](/coti-documentation/privacy-on-avalanche/networks.md) — Fuji (host) + COTI Testnet (private execution) parameters.
* [**Interactive PoD architecture on Fuji (pod.coti.io/avalanche)**](https://pod.coti.io/avalanche/index.html) — Live demo: MpcAdder journey across Avalanche Fuji, relayer, and COTI.
* [**Learn about fees**](/coti-documentation/privacy-on-avalanche/how-poa-fees-work.md) — How PoA/PoD fees split across COTI and Fuji (paid in AVAX).
* [**Millionaires demo**](https://millionaire.demo.coti.io) — Live demo (includes an Avalanche Fuji route).

## Further resources

* [**Examples**](https://github.com/coti-io/coti-contracts/tree/main/contracts/pod/examples) — Contract examples in `@coti-io/coti-contracts`.
* [**PoD SDK documentation**](https://github.com/cotitech-io/coti-pod-sdk/tree/main/docs) — Full SDK docs on GitHub.
* [**General Privacy on Demand section**](/coti-documentation/privacy-on-demand.md) — Multi-host PoD overview (not Avalanche-only).

***

This section is the **Avalanche Fuji–first** companion to Privacy on Demand: same PoD pattern, with Fuji C-Chain network constants, `PodUserFuji` presets, SnowScan explorers, and AVAX fee context. For integration, use [`@coti-io/pod-sdk`](https://www.npmjs.com/package/@coti-io/pod-sdk) (TypeScript) and [`@coti-io/coti-contracts`](https://github.com/coti-io/coti-contracts) (Solidity), plus the links below.

## Fuji at a glance

| Parameter         | Value                                                |
| ----------------- | ---------------------------------------------------- |
| Network           | Avalanche Fuji C-Chain                               |
| Chain ID          | `43113`                                              |
| Native token      | AVAX                                                 |
| RPC               | `https://api.avax-test.network/ext/bc/C/rpc`         |
| Explorer          | [testnet.snowscan.xyz](https://testnet.snowscan.xyz) |
| Inbox             | `0xAb625bE229F603f6BBF964474AFf6d5487e364De`         |
| Private execution | COTI Testnet (`7082400`)                             |
| Solidity preset   | `PodUserFuji`                                        |

Full tables: [Avalanche Fuji](/coti-documentation/privacy-on-avalanche/networks/fuji.md).

## Who this documentation is for

| Audience                                      | What you will get here                                                                                                                   |
| --------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------- |
| **Product, compliance, and business readers** | Plain-language model of privacy on Avalanche + COTI, where data lives, and what “async” private operations mean in practice.             |
| **Architects and technical leads**            | End-to-end diagrams for the **Fuji ↔ COTI** path, component roles, and domain boundaries.                                                |
| **Developers**                                | Fuji-focused map from concepts to Solidity/TypeScript (`PodUserFuji`, AVAX fees, SnowScan), plus pointers to the authoritative SDK docs. |

## Table of contents

### Start here

1. [Getting started on Avalanche Fuji (Day 0)](/coti-documentation/privacy-on-avalanche/getting-started-fuji.md) — Wallet, faucet, Hardhat/Foundry, SnowScan.

### Understand first (readable without writing code)

2. [What is Privacy on Avalanche?](/coti-documentation/privacy-on-avalanche/what-is-privacy-on-avalanche.md) — Problem, promise, and constraints with Fuji as the host chain.
3. [How a private request travels end to end](/coti-documentation/privacy-on-avalanche/how-a-private-request-travels-end-to-end.md) — Timeline from user action on Fuji to decrypted result.
4. [Architecture and main components](/coti-documentation/privacy-on-avalanche/architecture-and-components.md) — Where **Inbox**, **MPC executor**, **PodUser**, and **PodLib** sit, with diagrams.
5. [Networks](/coti-documentation/privacy-on-avalanche/networks.md) — [Avalanche Fuji](/coti-documentation/privacy-on-avalanche/networks/fuji.md) (host) and [COTI Testnet](/coti-documentation/privacy-on-avalanche/networks/coti-testnet.md) (execution).
6. [Glossary](/coti-documentation/privacy-on-avalanche/glossary.md) — Short definitions of terms you will see in PoD and SDK docs.

### Deeper context

7. [Async private operations (why it is not instant)](/coti-documentation/privacy-on-avalanche/async-private-operations.md) — What “pending” means and why UX must reflect it.
8. [How do PoA fees work?](/coti-documentation/privacy-on-avalanche/how-poa-fees-work.md) — Two-way Inbox budgets in AVAX, oracle conversion, and a worked gas-unit example.
9. [For developers: mapping concepts to the SDK](/coti-documentation/privacy-on-avalanche/for-developers-mapping-to-the-sdk.md) — Checklists and links to the [PoD SDK documentation on GitHub](https://github.com/cotitech-io/coti-pod-sdk/tree/main/docs).

### Tutorials (hands-on)

10. [Tutorials: building PoD dApps on Avalanche](/coti-documentation/privacy-on-avalanche/tutorials-privacy-on-avalanche.md) — When to use **MpcLib / PodLib** primitives vs **custom COTI + Fuji** contracts.
11. [TypeScript PoD SDK (`CotiPodCrypto`, `PodContract`)](/coti-documentation/privacy-on-avalanche/typescript-pod-sdk.md) — Encryption/decryption, fee estimation, method calls, and request ID extraction.
12. [Cookbook: private investor allocations with PoD](/coti-documentation/privacy-on-avalanche/cookbook-private-investor-allocations.md) — Start from a familiar public Fuji allocation dApp, then make allocation reads and withdrawals private with PoD.
13. [Tutorial: private Adder on Avalanche Fuji](/coti-documentation/privacy-on-avalanche/tutorial-private-adder-fuji.md) — Minimal primitive-only adder: `PodUserFuji`, AVAX fees, TypeScript crypto.
14. [Tutorial: custom privacy logic with PoD](/coti-documentation/privacy-on-avalanche/tutorial-custom-logic.md) — Encrypted messaging shape: `DirectMessageCotiSide` + Fuji orchestrator.

## Official technical reference

The machine-readable contracts, types, and APIs live in the open-source SDK. Treat this book chapter as the **human-oriented companion**; treat the repository as the **source of truth** for signatures, fees, and network constants:

* [COTI PoD SDK — documentation index](https://github.com/cotitech-io/coti-pod-sdk/tree/main/docs)


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