What is a blockchain
A blockchain is a network of computers that jointly maintain a shared record of transactions. Each blockchain is its own independent network — a token on Ethereum and a token on Polygon are not interchangeable unless explicitly moved between them. When you send a transaction or interact with a protocol, you do so on a specific chain. Sending tokens to the wrong chain means they can be lost.Supported chains
Cobo Agentic supports two categories of chains: EVM-compatible chains and Solana. These categories differ in address format, token standard, and contract interaction model — see EVM vs. Solana for a full comparison.EVM chains
EVM chains follow the same technical rules as Ethereum and use a numeric chain ID to identify each network. Each EVM chain has a unique numeric chain ID so tools know which network you’re on.| Chain | Chain identifier | EVM chain ID |
|---|---|---|
| Ethereum mainnet | ETH | 1 |
| Base mainnet | BASE_ETH | 8453 |
| Polygon PoS mainnet | MATIC | 137 |
| Arbitrum One | ARBITRUM_ETH | 42161 |
| Optimism mainnet | OPT_ETH | 10 |
| Avalanche C-Chain | AVAXC | 43114 |
| BNB Smart Chain | BSC_BNB | 56 |
| Tempo mainnet | TEMPO_TEMPO | — |
| Ethereum Sepolia (testnet) | SETH | 11155111 |
| Base Sepolia (testnet) | TBASE_SETH | 84532 |
| Tempo testnet (testnet) | TTEMPO_TEMPO | — |
Solana
Solana uses a cluster name rather than a numeric chain ID to identify each network.| Cluster | Chain identifier |
|---|---|
| Solana mainnet | SOL |
| Solana devnet (testnet) | SOLDEV_SOL |
EVM vs. Solana
Cobo supports both EVM-compatible chains and Solana. These two ecosystems work differently:| EVM (Ethereum, Base, Polygon) | Solana | |
|---|---|---|
| Address format | 0x-prefixed hex, 42 characters | Base58, ~44 characters |
| Token standard | ERC-20 | SPL |
| How contracts are called | Encoded function data | Instructions + account list |
| Fee unit | Gwei (fractions of ETH or MATIC) | Lamports (fractions of SOL) |
Layer 2 chains
Some EVM chains — including Base, Arbitrum, and Optimism — are Layer 2 (L2) chains. They process transactions faster and more cheaply than Ethereum mainnet by handling activity off the main chain, then periodically recording a summary back to Ethereum for security. From a user’s perspective, L2 chains work just like Ethereum: same address format, same token standards, same contract interaction model. The main practical differences are:- Gas fees on L2 are typically 10–100× cheaper than Ethereum mainnet.
- Bridge exits back to Ethereum vary by rollup type: optimistic rollups (Base, Optimism) require a challenge period of up to 7 days; ZK rollups can settle in minutes to hours.
- Protocols like Uniswap deploy separate contracts on each L2 — the contract addresses differ across networks.