0xio DEX

Status: Live on Devnet The 0xio DEX is live at dex.0xio.xyz. Cross-chain swaps between OCT and ETH are available on devnet.

Overview

0xio DEX is a cross-chain swap protocol that enables users to swap native tokens across chains, starting with OCT ↔ ETH between Octra and Ethereum Sepolia. The protocol uses a solver-based architecture with on-chain escrow and oracle verification.

How It Works

OCT → ETH

Connect Wallets

Connect your 0xio wallet (Octra) and MetaMask (Sepolia)

Get Quote

Enter the OCT amount and the solver provides a real-time quote with TWAP pricing

Lock OCT

OCT is locked in the SwapVault contract on Octra with a minimum receive commitment

Solver Fills

The solver detects the lock, sends ETH to your Sepolia address (~30s)

Oracle Attests

The oracle independently verifies the ETH was sent and attests on-chain

Settlement

After a challenge window, the solver claims the locked OCT

ETH → OCT

Connect Wallets

Connect MetaMask (Sepolia) and 0xio wallet (Octra)

Lock ETH

ETH is locked in the EthEscrow contract on Sepolia

Solver Sends OCT

The solver detects the lock and sends OCT to your Octra address

Solver Records the Fill

The solver calls fill() on the escrow with the Octra transaction hash

Oracle Attests + Settlement

The oracle verifies the OCT payout and attest() is recorded; after the challenge window the solver settles and receives the locked ETH

You are paid first: the solver sends OCT before it claims anything on Ethereum. If the solver never pays, the ETH stays in the escrow and you refund it after the lock expiry. The timing risk sits with the solver: a lock that expires before fill() is recorded can no longer be claimed.

Features

Cross-Chain Swaps: OCT ↔ ETH between Octra and Ethereum Sepolia
TWAP Pricing: 5-minute time-weighted average prices from CoinGecko + DexScreener
On-Chain Rate Protection: min_receive committed at lock time, so the solver can’t underpay
Slippage Control: Configurable slippage tolerance (0.1%, 0.5%, 1%, or a custom value up to 5%)
Liquidity Display: Real-time solver balance shown before swap
Network Detection: Auto-prompts MetaMask to switch to Sepolia
Live swap tracking: Every swap shows three steps (sent from your wallet, on the way, arrived) with a timer, survives a page reload, and offers a one-click refund when a swap can’t be filled
Activity: Live-updating transaction list with on-chain state at dex.0xio.xyz/history
DEX Stats: Volume, fees, solver status at dex.0xio.xyz/stats
Price Chart: Live OCT/USD chart next to the swap card (a compact price strip on phones)

Security

The protocol is built around a layered defense model: at no point can the solver underpay or the user lose locked funds.

5-Layer Defense

Layer	Protection
Solver Bond	20K OCT staked as collateral, slashed on fraud
On-Chain Rate Commitment	`min_receive` prevents solver from underpaying
Oracle Verification	Independent fill verification before attestation
Challenge Window	Dispute period after attestation, before the solver can settle
Stale Fill Refund	User reclaims funds if oracle doesn’t attest within timeout

Key Security Properties

Pay first, claim later: The solver delivers the destination tokens before it records fill(), and claims the locked funds only after the oracle attests and the challenge window passes
Idempotent payouts: Every solver transaction is stored before broadcast and retried with the same bytes, so a crash or timeout never pays twice; an unclear payout stops for manual review instead of being resent
Fee snapshot: Fee rate locked at swap time, can’t be changed retroactively
Reentrancy guard: All ETH transfer functions protected
Emergency refund: Owner can refund unfilled swaps (blocked after fill)
Reconciliation: The solver periodically reconciles its database with on-chain state and only ever moves a swap forward

Contract Addresses (Devnet)

Contract	Network	Address
SwapVault v7	Octra Devnet	`octHqBuw3TGsgeGpu6GiumRTjQwc8VCRAo1ANhy5zL4ZVPc`
EthEscrowV2	Sepolia	`0x835454daE518108105BC2ac22cb11738A5D69554`
Solver Wallet	Octra	`oct4Ay2HKoKbVSndUVdDaf1gxtYhdXeRVpkHvv43rhRoxio`
Solver Wallet	Sepolia	`0x3ec4bd68e2E3190FB3050005D8B9C132aFd9D684`
Treasury	Octra	`octCWWvj4EKPk1QA9TZrNTXZ6dJEbcQaS3fWAcmobPnyuqt`
Treasury	Sepolia	`0x80961b1e16D483c7EB5CA32e1fFd8157E5188598`

Architecture

User (0xio Wallet + MetaMask)
    │
    ▼
Frontend (dex.0xio.xyz)
    │
    ├── Quote: Solver API (solver.0xio.xyz)
    │     └── TWAP pricing from Oracle (oracle.0xio.xyz)
    │
    ├── OCT→ETH: SwapVault v7 (Octra) → Solver sends ETH (Sepolia)
    │
    └── ETH→OCT: EthEscrowV2 (Sepolia) → Solver sends OCT (Octra)

Swap Lifecycle (OCT → ETH)

lock() → fill() → attest() → [challenge window] → settle()
  │        │         │                                │
  │        │         │                                └── Solver gets OCT
  │        │         └── Oracle verifies ETH was sent
  │        └── Solver sends ETH + posts dest tx hash
  └── User locks OCT with min_receive commitment

Swap Lifecycle (ETH → OCT)

lock() → send OCT → fill() → attest() → [challenge window] → settle()
  │         │          │         │                                │
  │         │          │         │                                └── Solver gets ETH
  │         │          │         └── Oracle verifies the OCT payout
  │         │          └── Solver records the Octra tx hash on the escrow
  │         └── Solver pays OCT to the user first
  └── User locks ETH in EthEscrowV2

Fee Structure

Parameter	Value
Swap fee	0.5% (50 bps)
Fee destination	Protocol treasury (per-chain)
Minimum swap (OCT→ETH)	10 OCT (the vault’s minimum fee makes smaller locks fail)
Minimum swap (ETH→OCT)	0.001 ETH
Maximum swap	10,000 OCT / 10 ETH

Services

Service	URL	Role
DEX Frontend	dex.0xio.xyz	Swap interface
Activity	dex.0xio.xyz/history	Transaction list + on-chain state
DEX Stats	dex.0xio.xyz/stats	Volume, fees, solver status
Solver API	solver.0xio.xyz	Quote, swap tracking, health
Oracle	oracle.0xio.xyz	TWAP prices, fill verification

Solver API

GET /api/quote

Get a swap quote with current TWAP pricing.

GET https://solver.0xio.xyz/api/quote?from=OCT&to=ETH&amount=100

Response includes: rate, receive amount, fee, liquidity availability, intent hash.

GET /api/swap/:id

One swap by id: the quote intent_hash for OCT→ETH, or escrow_ plus the lowercase keccak256 of the intent hash for ETH→OCT. Returns 404 when the solver has not seen it yet.

GET /api/swaps

List recent swaps with status tracking. ?address= filters by source or destination address (case-insensitive).

GET /api/chains

Supported chains/tokens, the live contract addresses (SwapVault, EthEscrow), solver wallets and the lock limits (min_lock_oct, min_lock_eth). The DEX frontend locks only into its pinned contracts and pauses swaps if this endpoint reports different ones.

GET /api/health

Solver status: RPC connectivity, bond amount, liquidity on both chains.

GET /api/price

Proxied oracle price feed (no API key needed from frontend).

Refund Mechanisms

Scenario	Mechanism
Solver never fills	User taps Refund on the swap card or the Activity page once the lock expiry passes (`refund()`)
Solver fills but oracle never attests	Same Refund button after the stale-fill window (`refundStaleFill()` / `refund_stale_fill`)
Emergency	Owner calls `emergencyRefund()` (immediate, unfilled swaps only)

Repo	Role
0xio-solver	Rust solver backend (Axum + Tokio)
0xio-oracle	Price feeds (TWAP) + fill verification
@0xio/sdk	Octra wallet SDK for DApp integration

Roadmap

Near Term

Solana support (SOL ↔ OCT)
Multi-token support (wOCT, USDC)
Multi-solver competition
Mainnet deployment

Medium Term

Liquidity pools (CLMM)
Limit orders
Advanced routing (multi-hop, split orders)

Long Term: Cross-Chain Privacy Layer

Accept wETH/wSOL on their native chains, encrypt via Octra’s FHE, transfer privately, withdraw anywhere
Octra becomes a privacy middleware: users put in wETH, get out wETH, with full amount privacy in between
FHE-powered private swaps (AMM operating on encrypted data)
Relayer network for gasless, unlinkable withdrawals
Compliance via selective disclosure (viewing keys)

Cross-Chain Privacy Layer: Full Design

Deep dive into how 0xio uses Octra’s FHE as a privacy backend for any blockchain. Architecture, phases, and comparison with Umbra, Railgun, and Aztec.

Getting Started

Core Concepts

Wallet Guide

Products

Overview

How It Works

OCT → ETH

ETH → OCT

Features

Security

5-Layer Defense

Key Security Properties

Contract Addresses (Devnet)

Architecture

Swap Lifecycle (OCT → ETH)

Swap Lifecycle (ETH → OCT)

Fee Structure

Services

Solver API

GET /api/quote

GET /api/swap/:id

GET /api/swaps

GET /api/chains

GET /api/health

GET /api/price

Refund Mechanisms

Roadmap

Near Term

Medium Term

Long Term: Cross-Chain Privacy Layer

Cross-Chain Privacy Layer: Full Design

​Overview

​How It Works

​OCT → ETH

​ETH → OCT

​Features

​Security

​5-Layer Defense

​Key Security Properties

​Contract Addresses (Devnet)

​Architecture

​Swap Lifecycle (OCT → ETH)

​Swap Lifecycle (ETH → OCT)

​Fee Structure

​Services

​Solver API

​GET /api/quote

​GET /api/swap/:id

​GET /api/swaps

​GET /api/chains

​GET /api/health

​GET /api/price

​Refund Mechanisms

​Related Repos

​Roadmap

​Near Term

​Medium Term

​Long Term: Cross-Chain Privacy Layer

Cross-Chain Privacy Layer: Full Design

Overview

How It Works

OCT → ETH

ETH → OCT

Features

Security

5-Layer Defense

Key Security Properties

Contract Addresses (Devnet)

Architecture

Swap Lifecycle (OCT → ETH)

Swap Lifecycle (ETH → OCT)

Fee Structure

Services

Solver API

GET /api/quote

GET /api/swap/:id

GET /api/swaps

GET /api/chains

GET /api/health

GET /api/price

Refund Mechanisms

Related Repos

Roadmap

Near Term

Medium Term

Long Term: Cross-Chain Privacy Layer