Privy Server Wallets

⏱️ 3 min read

Overview

This guide points to a reference repository that shows you how to integrate DeFindex vaults using Privy server wallets enabling fully automated, server-side deposits, withdrawals, and cross-chain bridging with zero user interaction.

The pattern relies on Privy's Authorization Key (TEE-backed) to sign Stellar transactions from your backend, making it ideal for custodial products, bots, and programmatic yield strategies.

Repository

defindex-io/privy-defindex-guide

What the Repository Covers

Topic	Description
Privy setup	App ID, TEE activation, Authorization Key generation
Stellar wallet	Creation, XLM funding via Friendbot, USDC trustline
EVM wallet	Base EVM wallet with sendTransaction
Deposit	Full signing flow: XDR → hash → rawSign → broadcast
Withdraw	Withdraw by amount or by shares (% redemption)
Bridge	Base USDC → Stellar → Defindex vault via Sodax
Gotchas	9 documented edge cases with root causes and fixes

Architecture at a Glance

Your Server (P-256 Authorization Key)
       │  signs every request
       ▼
Privy TEE
  ├── Stellar wallet (Tier 2) — rawSign only
  └── EVM wallet    (Tier 3) — full sendTransaction

Defindex API (api.defindex.io)
  ├── POST /vault/{addr}/deposit         → unsigned Soroban XDR
  ├── POST /vault/{addr}/withdraw        → unsigned Soroban XDR
  ├── POST /vault/{addr}/withdraw_shares → unsigned Soroban XDR
  └── POST /send                         → { txHash }

All vault operations follow the same signing loop:

1. Authenticated POST to Defindex API → receive unsigned XDR

2. Parse XDR → hash it

3. privy.rawSign(walletId, { hash }) → Ed25519 signature

4. Attach DecoratedSignature to the envelope

5. POST signed XDR to /send

Quick Start

git clone https://github.com/paltalabs/privy-defindex-guide
cd privy-defindex-guide
pnpm install
cp .env.example .env
# Fill in: PRIVY_APP_ID, PRIVY_APP_SECRET, PRIVY_AUTHORIZATION_PRIVATE_KEY, DEFINDEX_API_KEY

pnpm example:deposit          # Deposit into Defindex XLM vault (testnet)
pnpm example:withdraw         # Withdraw by amount (testnet)
pnpm example:withdraw-shares  # Withdraw by shares / percentage (testnet)
pnpm example:bridge           # Base USDC → Stellar → Defindex vault (mainnet)

Prerequisites

• Privy app with TEE enabled and an Authorization Key configured

• Defindex API key — request access on Discord

Additional Resources

• Privy Documentation

• Defindex API Reference

• Sodax Bridge Documentation