Crypto wallet infrastructure is the software that lets an app give its users crypto wallets, and lets those wallets work across several blockchains without the users noticing which one they are on. A crypto wallet does not store coins. It stores the user's key, the secret number that proves ownership on a blockchain, and it shows the user's balance.
There are many blockchains, such as Bitcoin, Ethereum, Polygon and Solana. Each has its own fees, and many have their own address format and their own way of signing a payment. A user who must understand all this will usually give up. Wallet infrastructure hides these differences. The app calls one set of functions, such as "create wallet", "show balance" and "send". The infrastructure then talks to whichever blockchain is needed.
Take, for example, a ticketing app in Chennai that issues concert tickets as tokens. A fan signs up with only her email address. The wallet infrastructure creates a wallet for her in the background. She never sees a key or a long address. When she buys a ticket, the app sends the token to her wallet. The token may live on one blockchain, while the payment is made on another. The fan sees only "Ticket received".
The hardest part is the key. If the app stores users' keys carelessly, a single breach could empty every wallet. So wallet infrastructure protects keys with strong encryption. Many providers split each key into shares, in the same way as MPC wallets and crypto custody. One share stays on the user's phone and one with the provider, so that neither can move the money alone.
Wallet infrastructure works closely with a crypto on-ramp, which turns the user's rupees into crypto. It also holds tokens issued by real-world asset tokenisation platforms, such as a tokenised bond. Compare an ordinary digital wallet on a phone, which stores card tokens for paying in shops rather than keys to a blockchain.