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What is Umbra?

Umbra adds a privacy layer on top of standard Solana SPL and Token-2022 tokens. It lets you:
  • Shield balances — move tokens from an Associated Token Account (ATA) into an EncryptedTokenAccount (ETA) where the balance is hidden from everyone except authorized viewers.
  • Transfer anonymously — write a Stealth Pool Note into a shared mixer tree, then burn it from any wallet with no on-chain linkage to the sender.
  • Control who sees what — grant selective viewing access to auditors or compliance systems without exposing your full history.
Everything runs on Solana using a combination of on-chain programs and Arcium multi-party computation (MPC) for the confidential arithmetic.
You do not need to understand MPC or zero-knowledge proofs to use Umbra. The SDK handles all cryptographic operations for you.

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Key Terms

These are the nouns and verbs you will see throughout the SDK and the rest of these docs:
  • ATA — AssociatedTokenAccount. A standard SPL Associated Token Account holding plaintext tokens. Source/destination of deposits and withdrawals.
  • ETA — EncryptedTokenAccount. An Umbra-managed account whose balance is encrypted. Has two modes: MXE-only (only the Arcium MPC network can decrypt) and Shared (you can also decrypt locally with your viewing key).
  • Stealth Pool Note — an anonymous note stored as a commitment in the on-chain Indexed Merkle Tree. Senders create notes; either the original sender (self-burnable) or a designated recipient (receiver-burnable) burns them later to redeem the value.
  • Burn — the operation that redeems a Stealth Pool Note: it reveals the note’s nullifier (preventing double-spend), discharges the value into either an ETA or an ATA, and emits no on-chain link back to the creator.

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Core Concepts at a Glance

Encrypted Balances

Shield any SPL or Token-2022 token balance in an EncryptedTokenAccount. Only you — and anyone you explicitly grant access to — can see the amount.

Stealth Pool

Break the on-chain link between sender and recipient using a shared Merkle tree of Stealth Pool Notes and zero-knowledge burn proofs.

SDK

One TypeScript package, @umbra-privacy/sdk. The ZK prover, indexer client, and relayer client all ship as subpath modules of the same package.

Indexer API

A read-only REST API for Stealth Pool Note records and Merkle proofs — used internally by the SDK and available for direct integration.

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How It Fits Into Your Stack

Umbra is designed to slot into an existing Solana application. You bring your wallet adapter; Umbra handles the rest. 
Your App
  └── Wallet (Phantom, Solflare, etc.)
        └── Umbra SDK (@umbra-privacy/sdk)
              ├── Solana RPC     — sends and confirms transactions
              ├── Arcium MPC     — performs confidential computation off-chain
              ├── Umbra Indexer  — indexes Stealth Pool Notes + Merkle proofs
              ├── Umbra Relayer  — submits burn transactions for the user
              └── ZK prover      — Groth16 (snarkjs), runs in a Web Worker

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Program IDs

The Umbra on-chain program is deployed at different addresses per network:
  • Mainnet: UMBRAD2ishebJTcgCLkTkNUx1v3GyoAgpTRPeWoLykh
  • Devnet: DSuKkyqGVGgo4QtPABfxKJKygUDACbUhirnuv63mEpAJ
The SDK resolves the correct program address automatically based on the network parameter.

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Supported Networks

  • mainnet — Production. wSOL, USDC, USDT, UMBRA, CASH.
  • devnet — Development and integration testing. wSOL, dUSDC, dUSDT, STREAMFLOW. Get dUSDC / dUSDT test tokens at faucet.umbraprivacy.com.
  • localnet — Local validator (development).

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Next Steps

Quickstart

Install the SDK and run your first deposit + burn in under 5 minutes.

How Umbra Works

Understand the privacy model before you start building.