--- name: gdex-bridge-5c10d9a460e6 description: Cross-chain bridging — get estimates and execute native token transfers between EVM chains, Solana, and Sui via ChangeNow --- # GDEX: Cross-Chain Bridge Bridge **native tokens** between supported chains with quote previews and time estimates. Uses ChangeNow as the bridge provider (StarGate support exists but is currently disabled). > **Moving USDC?** The unified USDC wallet has its own capped USDC bridge (`estimateUsdcBridge` / `executeUsdcBridge`) and trades can auto-bridge USDC for you. See **gdex-usdc-wallet**. ## When to Use - Moving native tokens from one chain to another (e.g., ETH on Ethereum → ETH on Base) - Getting a bridge estimate before executing - Checking bridge order history ## Prerequisites - `@gemachdao/gdex-skill` installed - Authenticated via managed-custody sign-in — see **gdex-authentication** - Session keypair (sessionPrivateKey + sessionKey) from sign-in flow ## Backend Endpoints | Method | Path | Purpose | |--------|------|---------| | `GET` | `/v1/bridge/estimate_bridge` | Get a bridge quote | | `POST` | `/v1/bridge/request_bridge` | Execute a bridge (encrypted) | | `GET` | `/v1/bridge/bridge_orders` | List bridge order history | ## 1. Get a Bridge Estimate (Quote) ```typescript import { GdexSkill, GDEX_API_KEY_PRIMARY } from '@gemachdao/gdex-skill'; const skill = new GdexSkill(); skill.loginWithApiKey(GDEX_API_KEY_PRIMARY); const estimate = await skill.estimateBridge({ fromChainId: 1, // Ethereum toChainId: 8453, // Base amount: '1000000000000000000', // 1 ETH in wei }); ``` ### Query Parameters | Parameter | Type | Required | Description | |-----------|------|----------|-------------| | `fromChainId` | `number` | Yes | Source chain ID | | `toChainId` | `number` | Yes | Destination chain ID | | `amount` | `string` | Yes | Amount in **raw token units** (wei for EVM, lamports for Solana) | ### Estimate Response ```typescript interface BridgeEstimate { tool: string; // "ChangeNow" fromChainId: number; fromAmount: string; // input amount (raw units) toChainId: number; estimateAmount: string; // estimated output (raw units) minEstimateTime: number; // seconds maxEstimateTime: number; // seconds } ``` ### Error Codes | Code | Meaning | |------|---------| | 101 | Missing params / same chain / unsupported chain | | 106 | ChangeNow API error | | 107 | Unsupported chain (e.g., Fraxtal 252) or catch-all | ## 2. Execute a Bridge The bridge endpoint requires an **AES-encrypted `computedData` payload** containing ABI-encoded parameters and a secp256k1 signature — the same pattern as managed spot trades. ```typescript import { GdexSkill, GDEX_API_KEY_PRIMARY, generateGdexSessionKeyPair, buildGdexSignInMessage, buildGdexSignInComputedData, } from '@gemachdao/gdex-skill'; import { ethers } from 'ethers'; // After sign-in (you have sessionPrivateKey from the auth flow): const result = await skill.requestBridge({ fromChainId: 1, // Ethereum toChainId: 8453, // Base amount: '1000000000000000000', // 1 ETH in wei userId: controlAddress, sessionPrivateKey, apiKey: GDEX_API_KEY_PRIMARY, }); if (result.isSuccess) { console.log('TX hash:', result.hash); console.log(`ETA: ${result.minTime}-${result.maxTime}s`); } ``` ### Encryption Protocol The SDK handles this automatically, but for reference: 1. **ABI-encode data**: `['string', 'uint64', 'uint64', 'string']` → `[amount, fromChainId, toChainId, nonce]` 2. **Sign message**: `"request_bridge-{userId.toLowerCase()}-{dataHex}"` using secp256k1 session key 3. **Encrypt JSON**: `{ userId, data, signature }` → AES-256-CBC with key/IV derived from SHA256(apiKey) 4. **POST body**: `{ computedData: "" }` ### Bridge Result ```typescript interface BridgeResult { isSuccess: boolean; hash: string | null; // source chain tx hash message: string; minTime?: number; // seconds maxTime?: number; // seconds error?: string; // on failure } ``` ### Error Codes | Code | Meaning | |------|---------| | 101 | Missing params / same chain / unsupported chain | | 102 | Invalid or reused nonce | | 103 | User wallet not found on chain | | 104 | Unauthorized (signature verification failed) | | 105 | Below minimum bridge amount / insufficient balance | ## 3. Get Bridge Order History ```typescript import { buildGdexUserSessionData, GDEX_API_KEY_PRIMARY } from '@gemachdao/gdex-skill'; const data = buildGdexUserSessionData(sessionKey, GDEX_API_KEY_PRIMARY); const orders = await skill.getBridgeOrders({ userId: controlAddress, data, }); console.log(`${orders.count} bridge orders`); orders.bridgeOrders.forEach(o => { console.log(`${o.fromChainId} → ${o.toChainId}: ${o.fromAmount} (tx: ${o.txHash})`); }); ``` ### Response ```typescript interface BridgeOrdersResponse { count: number; bridgeOrders: BridgeOrder[]; } interface BridgeOrder { userId: string; fromChainId: number; toChainId: number; fromAmount: string; estimateToAmount: string; fromWallet: string; toWallet: string; txHash: string; requestTime: number; } ``` ## Supported Chains for Bridging Controlled by backend `config.bridgeSupportedChainIds`. Known supported: | Chain | ChainId | |-------|---------| | Ethereum | `1` | | Optimism | `10` | | BSC | `56` | | Sonic | `146` | | Base | `8453` | | Arbitrum | `42161` | | Berachain | `80094` | > Robinhood Chain (`4663`) is tradeable but **not bridgeable** — fund it externally. | Solana | `622112261` | | Sui | `1313131213` | > **Fraxtal (252) is explicitly blocked** by the backend and will return error code 107. ## Key Points - **Native tokens only** — the bridge transfers the chain's native token (ETH, SOL, BNB, etc.), not arbitrary ERC-20s. - **Amounts in raw units** — use wei for EVM (1 ETH = `"1000000000000000000"`), lamports for Solana (1 SOL = `"1000000000"`). - **Minimum bridge amount** — each chain has a `minBridge` config (default 1 in native decimals). Below this triggers error 105. - **Nonce required** — each `requestBridge` call uses a unique nonce verified server-side. The SDK generates this automatically. - **ChangeNow provider** — all bridges currently go through ChangeNow (StarGate code exists but is disabled). ## Autonomous Agent Notes (Live-Tested) 1. **`estimateBridge` works with API key only (E2E verified).** No session key or full sign-in needed for quotes. 2. **`requestBridge` requires full managed-custody auth** (session key + ABI encoding + AES encryption). 3. **Bridge paths are non-obvious:** `GET /v1/bridge/estimate_bridge`, `POST /v1/bridge/request_bridge`, `GET /v1/bridge/bridge_orders`. Do NOT use `/v1/bridge/estimate` or `/v1/bridge/execute`. 4. **Fraxtal (252) is explicitly blocked** and returns error 107. 5. **Bridge times vary:** ETH→ARB is ~5-15 min, Solana→EVM can take longer. 6. **For autonomous pre-trade funding:** Use `estimateBridge` to check feasibility before committing. If `estimateAmount` is too low (high fee), consider alternative routes. ## Related Skills - **gdex-authentication** — Auth setup required for bridging - **gdex-portfolio** — Check balances on target chain after bridging - **gdex-spot-trading** — Trade on the destination chain after bridging --- Source attribution: GemachDAO Original project: https://github.com/GemachDAO/gdex-skill/blob/7e51b52977be7ada679d2cbe58107d14db83cd83/skills/gdex-bridge/SKILL.md License: MIT License information: https://opensource.org/license/mit Original upstream instructions; downloaded from Mega AI Hub. ## Upstream license notice MIT License Copyright (c) 2026 GemachDAO Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. # Mega AI Hub resource metadata Creator / publisher: GemachDAO Original project: https://github.com/GemachDAO/gdex-skill/blob/7e51b52977be7ada679d2cbe58107d14db83cd83/skills/gdex-bridge/SKILL.md Attribution basis: Source repository record Fields of work: Development & Engineering Roles: Backend Developer, Data Engineer, DevOps / SRE Specialties: API, Backend Tools: Changenow, @Gdexsdk/Gdex Skill Country applicability: Country not specified Classification basis: Source catalog labels Instruction SHA-256: 921ff83a7162cf1a75502ff33098cb1584883441596c67d2e185f9d4e8d9a4dd