EVM chain ID (integer), or one of "solana", "xrpl", "bitcoin", "tron", "stellar", "sui" (string). Supported chains: Ethereum (1), BNB Chain (56), Base (8453), Avalanche (43114), Polygon (137), Arbitrum (42161), Optimism (10), Chiliz (88888), Soneium (1868), Plume (98866), Sonic (146), Gnosis (100), Mantle (5000), Scroll (534352), Linea (59144), zkSync Era (324), Blast (81457), Taiko (167000), Ronin (2020), Celo (42220), Viction (88), opBNB (204), World Chain (480), Unichain (130), Ink (57073), Sei (1329), Berachain (80094), ApeChain (33139), XDC Network (50), Robinhood Chain (4663), Arc (5042), Solana ("solana"), XRP Ledger ("xrpl"), Bitcoin ("bitcoin"), Tron ("tron"), Stellar ("stellar"), Sui ("sui"). Bitcoin only supports token_balance with contractAddress "native". Tron, Stellar, and Sui support token_balance only. Moonbeam (1284) and Moonriver (1285) were retired on 2026-09-20 after both networks stopped producing blocks. GLMR and MOVR now live on Base (chainId 8453) as ERC-20s and are read with an ordinary token_balance condition; a request naming either retired chain returns 400.