How we warn users about look-alike scam addresses in our crypto wallet

tazvera — Sun, 01 Nov 2026 08:53:16 +0000

One of the most common crypto scams today does not hack anything. It just copies you.

It is called address poisoning. A scammer creates a wallet address that starts and ends with the same characters as someone you already pay, for example:

Real:  0x1234567890abcdef1234567890abcdef1234abcd
Fake:  0x1234ffffffffffffffffffffffffffffffffabcd

Most wallets show addresses shortened, like 0x1234…abcd. Both look identical. People copy the wrong one from their history and lose money.

I'm building Tazvera, a simple open source wallet in Hindi + English for first-time crypto users in India. For our users, this kind of scam is a real risk, so we built Tazvera Shield: a few simple checks that run on the confirm screen, before any coins leave the wallet.

What Shield checks

Look-alike address: same first 4 and last 4 characters as a contact or a past address, but a different middle → red warning, and the Send button stays locked until the user ticks "I checked every letter".
First-time address: never sent here before → a calm yellow note, no extra taps.
Burn and token contract addresses: sending to 0x000… or to a token's own contract → red warning (coins are usually lost forever).
Smart contract address: we ask the network for the code at that address (eth_getCode). If there is code, we show a gentle note.
Known address: a green "all clear", so normal payments stay fast.

The core check is tiny

function lookAlike(to, known) {
  to = to.toLowerCase();
  return known.find(k =>
    k.address !== to &&
    k.address.slice(2, 6) === to.slice(2, 6) &&   // same start
    k.address.slice(-4) === to.slice(-4)          // same end
  );
}

known is built only from data already on the user's phone: their address book and the addresses they sent to before. Nothing is uploaded.

Design choices that mattered

Warn only when it matters. Our first version showed too many warnings and checkboxes. Users started tapping "OK" without reading. Now a normal send is just: Send → PIN. Red appears only for real danger.
Show the full address, highlighted. On the confirm screen we show the whole address with the first 6 and last 4 characters in bold green, so people actually compare it.
Block, don't just inform. For red cases, the Send button is disabled until the user confirms they checked.

Try it / help us

App (test networks): https://app.tazvera.com
Code (MIT): https://github.com/tazvera/tazvera-wallet

Tazvera is a volunteer project by a solo founder, so I can't pay, but ideas, reviews and pull requests are very welcome. What other scam patterns should a wallet warn about? Tell me in the comments 🙏

I'm a solo founder with no tech background, building a Hindi crypto wallet in the open

tazvera — Thu, 29 Oct 2026 06:22:27 +0000

Hi dev.to! 👋

I'm Dattu from India. I don't come from a tech background, and I'm building Tazvera: a simple, self-custody crypto wallet in Hindi + English.

Why?

Most crypto wallets are in English and feel confusing for first-time users in India. Many people are scared of losing money or getting scammed. I want a wallet that feels as easy as a UPI app, in a language people understand.

What works today (testnet)

In-app wallet, no MetaMask needed (12 words + 6-digit PIN)
PIN for every send, app lock, "Test my 12 words" backup check
Send, receive, request with QR codes and a confirm screen
Built-in helper with answers in English, Hindi, Marathi and Gujarati
Shardeum Testnet, BNB Testnet and Ethereum Sepolia
Free TZT test token faucet

Try it: https://app.tazvera.com (test networks only, test coins have no value)

Tech

Plain HTML, CSS and JavaScript, ethers.js, hosted on Vercel. No build step.

I need help 🙏

This is a volunteer open source project (MIT). I'm a solo founder with no budget, so I can't pay. But if you'd like to help for free, I would be very grateful:

Review the code (especially wallet.js)
Report bugs or ideas in Issues
Send a pull request (translations, cleanup, tests)

👉 https://github.com/tazvera/tazvera-wallet

Every star, comment and suggestion helps a small project like this. Thank you for reading! 💚

DEV Community: tazvera