Testnet Chain ID Configuration

Problem

Staging environment sends mainnet chain IDs to APIs that only support testnet, causing 502 errors or unexpected behavior despite VITE_TESTNET_MODE=true being correctly set.

Context / Trigger Conditions

• •Relayr staging API returns 502 Bad Gateway
• •Network payload shows chain: 1 (mainnet) instead of chain: 11155111 (Sepolia)
• •VITE_TESTNET_MODE=true is confirmed set in Railway/build environment
• •Testnet explorers, RPCs, and other chain-specific features work correctly

Root Cause

The ALL_CHAIN_IDS and CHAINS constants in src/constants/index.ts were hardcoded to mainnet values, not using the environment-aware SUPPORTED_CHAIN_IDS from src/config/environment.ts.

Solution

1. •

   Check src/constants/index.ts for hardcoded chain ID arrays:

   typescript

   // BAD - hardcoded
   export const ALL_CHAIN_IDS = [1, 10, 8453, 42161] as const
   
   // GOOD - environment-aware
   import { SUPPORTED_CHAIN_IDS } from '../config/environment'
   export const ALL_CHAIN_IDS = SUPPORTED_CHAIN_IDS
   

2. •

   Ensure CHAINS object uses CHAIN_IDS from environment config as keys, not literals

3. •

   Verify components use ALL_CHAIN_IDS from constants, not hardcoded arrays

Key Files

• •src/config/environment.ts - Source of truth for IS_TESTNET, CHAIN_IDS, SUPPORTED_CHAIN_IDS
• •src/constants/index.ts - Must import and re-export environment-aware values
• •src/constants/chains.ts - Contract addresses (already environment-aware)

Chain ID Mapping

Verification

1. •Build staging: npm run build:staging
2. •Check network payload in browser devtools when creating a bundle
3. •Confirm chain IDs are Sepolia variants (11155111, etc.)

Notes

• •Railway has VITE_TESTNET_MODE=true set as a service variable
• •.env.staging is gitignored; Railway uses dashboard env vars
• •Vite requires VITE_* variables at BUILD time, not just runtime