How do I move my Bitcoin to bit21?

You don't. Type your existing 12 or 24-word recovery phrase into bit21 and the same addresses appear, holding the same coins. Nothing moves on-chain, no fee, no waiting. About thirty seconds.

What does self-custody actually mean?

You hold the private keys. No company, no exchange, no government sits between you and your coins. If bit21 vanished tomorrow, your seed phrase still opens your wallet in any BIP39-compatible app.

What if I lose my phone?

Bitcoin is not stored on your phone. It lives on the network. The seed phrase is the key. Back the seed up on paper or steel and you can restore the wallet on any device, any time.

Does bit21 collect any data about me?

No account, no email, no phone number, no KYC. The wallet itself sends nothing identifying when it queries the blockchain. We have no list of users to leak even if we wanted to.

Which Bitcoin address types are supported?

All four standard types: Legacy (1...), SegWit Compatible (3...), Native SegWit (bc1q...), and Taproot (bc1p...). You can pick a type per wallet and bit21 finds funds across all of them automatically on import.

What is the Vault feature?

A vault uses Bitcoin's CheckLockTimeVerify opcode to make coins literally unspendable until a chosen block height. Bitcoin's own consensus enforces the lock. Not bit21, not us. Useful when you want to hold long-term and stop yourself from touching the stack early.

What is the time-locked vault for?

Forced patience. Lock a chunk of Bitcoin for a year, two years, whatever you need. The protocol holds it; nobody can unlock it early, including the people who built bit21. If you tend to fiddle with your stack during volatility, this removes the option.

Is bit21 open source?

Yes. The wallet code is public for anyone who wants to inspect or verify it. Most users use the official apps. The source is there if you ever care to look.

Can I use bit21 on iPhone?

Yes, through the web app at wallet.bit21.app. It runs in any modern browser, iPhone included. A native iOS app is in the pipeline.

Why Bitcoin only? Why not other coins?

Every extra coin adds code, complexity, and attack surface. Multi-chain wallets have more places to break. bit21 stays focused on Bitcoin because that is the asset that warrants this level of care. Not a limitation. A choice.

Yes. You pay standard Bitcoin network fees when you send a transaction; those go to miners. bit21 takes no cut.

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April 14, 20266 min read

What Is a Self-Custody Bitcoin Wallet and Why It Matters

Name: bit21 Bitcoin Wallet
Author: bit21

Bitcoin was created to give people control over their own money. The entire point of the protocol is removing middlemen. Yet most people store their Bitcoin on exchanges, handing control right back to a third party.

Self-custody means holding your own private keys. Not your exchange's keys. Not your broker's keys. Yours. When you control the keys, you control the Bitcoin. Nobody can freeze it, seize it, or block your transactions.

How Bitcoin Wallets Actually Work

A Bitcoin wallet does not store Bitcoin. Bitcoin lives on the blockchain, a public ledger maintained by thousands of computers worldwide. What a wallet stores is the private key that proves you own a specific amount of Bitcoin at a specific address.

Think of it like a house. The Bitcoin is the house. The private key is the only key to the front door. Whoever holds that key controls the house. When you use an exchange, the exchange holds the key. When you use a self-custody wallet, you hold it.

Why Exchanges Are Risky

The collapse of FTX in November 2022 erased billions of dollars of customer funds overnight. Users who thought their Bitcoin was safe discovered they were unsecured creditors in a bankruptcy proceeding. Their Bitcoin was gone.

FTX was not unique. Mt. Gox (2014), QuadrigaCX (2019), Celsius (2022), BlockFi (2022), and Voyager (2022) all failed and took customer funds with them. The pattern is consistent: exchanges that hold your keys can lose your Bitcoin.

What Self-Custody Looks Like

When you set up a self-custody wallet, the software generates a random 12 or 24-word recovery phrase (also called a seed phrase). This phrase is the master key to all your Bitcoin addresses. Write it down and store it somewhere safe.

From this phrase, the wallet derives your private keys and public addresses. You can receive Bitcoin to your addresses and send it using your private keys. The wallet software handles the cryptography. You handle keeping the recovery phrase safe.

The Responsibility That Comes With It

Self-custody means accepting full responsibility. If you lose your recovery phrase, nobody can help you recover your Bitcoin. There is no customer support to call. There is no "forgot password" button. This is the tradeoff for true ownership.

For many people, this responsibility is worth the peace of mind. You never have to worry about an exchange freezing your account, a government seizing your assets, or a company going bankrupt with your money. Your Bitcoin is yours and only yours.

Getting Started

Start with a Bitcoin-only software wallet on your phone. Create a wallet, back up your recovery phrase on paper (not digitally), and send a small test amount from your exchange. Verify that everything works before moving larger amounts.

bit21 is built specifically for this. It supports all four Bitcoin address types (Legacy, SegWit, Native SegWit, and Taproot), requires no registration or identity verification, and encrypts everything locally on your device. No KYC. No tracking. Just Bitcoin.

Ready to take custody?

bit21 is a Bitcoin-only self-custody wallet. No KYC. No tracking. Your keys, your Bitcoin.

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