Why one address works on every EVM chain
Ethereum-compatible ("EVM") networks — BNB Chain, Polygon, Arbitrum, Base, and hundreds of smaller ones — all use the same account model and cryptography. Your private key produces the same 0x address on all of them. Adding a network to a wallet doesn't create anything new: it just tells the wallet where to look — which server to query and which network's coins it is displaying.
That's why in GaurdWallet a custom network reuses your existing address, and why funds "on a network you haven't added yet" are never lost — they sit on-chain waiting for you to add the network and look.
The four fields, demystified
| Field | What it is | Example (Base) |
|---|---|---|
| Chain ID | The network's unique number, signed into every transaction (EIP-155) so a transaction for one chain can't be replayed on another. Must be exactly right. | 8453 |
| RPC URL | The server your wallet sends balance queries and transactions through. Determines what you see, not what you own. | https://mainnet.base.org |
| Currency symbol | Ticker of the coin that pays gas on that network. | ETH |
| Decimals | Denomination of the native coin. 18 for virtually every EVM chain. | 18 |
An optional fifth field, the block explorer URL, only affects the "view in explorer" links — handy, not critical.
Where to get trustworthy values
- The network's official docs — every serious chain publishes its chain ID and public RPC endpoints. This is the canonical source.
- chainlist.org — a community registry of EVM networks (backed by the ethereum-lists GitHub repo) that aggregates chain IDs and working RPCs. Great for cross-checking; still glance at the official docs for anything involving serious money.
- Not from: a site that just asked you to connect a wallet, a Telegram DM, or a YouTube description. Wrong-parameter attacks are rare but real — see the threat model below.
Walkthrough: adding a network in two minutes
- Open Settings → Networks → Add network in your wallet.
- Enter the name, chain ID, RPC URL, symbol and decimals from the official docs.
- Let the wallet check the RPC. GaurdWallet calls
eth_chainIdon the endpoint before saving and warns you in two cases: the endpoint is unreachable, or it answers with a different chain ID than you typed — the single most useful validation, since it catches both typos and misconfigured endpoints. (You can still save anyway; the warning is information, not a wall.) - Save and open the Receive screen: your usual
0xaddress, now shown for the new network. - If you hold tokens there, add them by contract address — the wallet reads the symbol and decimals live from the chain.
What a bad RPC can and cannot do — the honest threat model
People worry about the RPC field more than it deserves, and about the chain ID less. Precisely:
- An RPC can never steal your keys. Keys stay in the wallet; the RPC only receives queries and already-signed transactions.
- A malicious RPC can lie to you: show a fake balance ("you received 5,000 USDT!") to bait you into some follow-up scam, hide transactions, censor your broadcasts, or log your address against your IP (a privacy, not custody, issue).
- A wrong chain ID mainly breaks things — transactions signed for chain 8453 are invalid on other chains by design (that is EIP-155 doing its job). The residual risk is signing for a chain you didn't intend while the RPC plays along; the
eth_chainIdpre-check closes exactly this gap.
Practical rule: take parameters from official docs, prefer well-known public endpoints, and treat "add this network to claim your airdrop" pages with the suspicion described in our extension-safety guide.
RPC overrides: same idea, different use
Separate from adding networks, most wallets (GaurdWallet included) let you override the RPC of a built-in network — useful when a default endpoint is slow in your region, when you run your own node for privacy, or when a provider rate-limits. Overriding an RPC changes your window onto the chain, nothing else; your keys, address and balances are untouched, and you can reset to the default at any time.
Quick answers
- Will my tokens disappear if I remove a network? No — removal only stops the wallet from displaying that chain. Add it back and everything reappears.
- Can two networks share a chain ID? Mainnets, no — uniqueness is the point of the registry behind chainlist.org. If a wallet ever shows you a duplicate-ID warning, one of the two entries is wrong or malicious.
- Why 18 decimals everywhere? Inherited from Ether's wei denomination; almost every EVM chain kept it. Only change it if the network's docs explicitly say otherwise.
- Do custom networks work with the dApp connector? Yes — once added, a dApp's "switch network" request (EIP-3326) can target it like any built-in chain.