START HERE · FROM BASICS TO SELF-CUSTODY
You buy bitcoin on an exchange, control it with a wallet and use a backup to make recovery possible. These things are connected, but each serves a different purpose. We will start with six terms you will encounter during your first transfer.
Bitcoin is a network where people can send digital money to one another. BTC is the unit of that money. You do not need to buy a whole bitcoin; its current issuance rules limit the total supply to approximately 21 million BTC.
Explain in the Atlas →The smallest unit on Bitcoin’s base network is called a satoshi, or sat for short. 1 BTC = 100,000,000 sats. You can therefore start with a small fraction of a bitcoin.
Explain in the Atlas →An address tells the wallet where to send a payment. You can share it to receive money; it is not a password. Before sending, check the entire address. Reusing an address or sharing it publicly can reveal which payments belong to you.
Explain in the Atlas →A private key is secret data that a wallet uses to sign a payment. The signature must satisfy the conditions for spending those bitcoins; for example, Multisig requires a specified number of signatures. Never share the key.
Explain in the Atlas →A list of recovery words that a compatible wallet can use to recreate its keys. Keep it offline and never send it to anyone. Full recovery may also require a passphrase or other information; the words are not a login password that support can reset.
Explain in the Atlas →A Bitcoin wallet does not deduct a payment from a single shared balance. It selects unspent portions of earlier payments, called UTXO. It spends each selected portion in full and usually returns any change to an address of its own.
Explain in the Atlas →The operator controls keys and withdrawal terms. You bear its operational, legal and insolvency risks; do not judge protection by the app’s name alone.
In a self-custodial mobile wallet, keys are on a network-connected device. A mobile app can also be custodial or a Watch-only Wallet; being on a phone does not imply you hold the keys.
A signing device is designed to keep keys separate from an ordinary computer. Verify authenticity, firmware and information on its display; the device does not remove the risk of a faulty backup.
Proceed step by step. A tick records only your progress, not verified safety; the state is stored locally if your browser allows it.
Seeing a BTC balance in an app does not yet mean that you control the bitcoin yourself. First, find out whether you can withdraw it and who holds the keys. In the next steps, you will try buying and moving it to your own wallet with a small amount.
Write down why you want to try bitcoin and how much you can spend on this trial. Include the fees. If losing the entire amount would make it difficult to cover everyday expenses, choose a smaller amount or postpone the purchase.
You will usually make your first purchase through an exchange or broker. Before signing up, find out who operates the service, how much you will pay and whether you can send the bitcoin you buy to your own wallet.
Before signing up, find the conditions for your country, the minimum withdrawal and its fee. Check that the service allows the small transfer you plan to make to your wallet. The links below help you verify this; they are not a ranking of providers.
An attacker does not need to break Bitcoin to take your money. They may try to get into your exchange account, take over your email or pretend to be support. Secure the account before depositing money.
The service may ask for identity documents and other information; this verification is called KYC. Submit it only through the real service’s verified process. An unsolicited contact must never receive your Seed Phrase, PIN or one-time codes. Do not allow them to control your device remotely.
A spot purchase means buying bitcoin itself with your money. Your first trial should take you through the full journey from payment to withdrawal into your own wallet. Use a supported payment method and only an amount you can afford to lose entirely.
A larger purchase is not needed to test functionality. Consider another transfer only after a small trial of self-custody and a usable backup.
A wallet is not a box containing bitcoins. The network records the coins; an app or device helps you work with keys and payment information. Some apps can only display a balance, while others sign payments. When choosing one, find out who holds the keys and how you would recover access if you lost the device.
Before changing custody, establish who holds the keys, how a signature is created and how recovery works. A Watch-only Wallet without the relevant keys cannot spend funds by itself.
If you choose a Hardware Wallet, check the seller, device provenance and instructions for the exact model. A brand or intact packaging is not complete verification.
The following links lead to manufacturer documentation. Before buying, compare supported features, backups, updates and security models; this is not a ranked recommendation list.
A Seed Phrase is a set of recovery words. A compatible wallet can use them to derive the keys again, even if you lose the original device; you do not need its PIN for this. If you also use a passphrase, you need both the exact words and that passphrase to recover the same wallet. Some setups need additional information; Multisig also requires the specified number of signatures.
A passphrase is an optional addition to a BIP39 backup, not a PIN. If you use one, record it exactly and keep it separately from the words: even a typo creates a different valid wallet. Also retain the backup format, key derivation paths and any Output Descriptor, which describes the wallet setup. The correct words alone may not be enough to find all your funds.
Create a receiving address in a trusted wallet and compare it in full with the withdrawal destination. Checking only the beginning and end is not enough.
A small test limits the scale of a possible mistake, not every threat. If details disagree or you are under pressure, do not confirm the transfer.
A transfer on Bitcoin’s base network carries a fee. It is calculated from the transaction’s virtual size and the chosen fee rate, rather than as a percentage of the amount sent. One factor affecting size is the number of UTXOs the wallet uses: unspent portions of earlier payments. An incoming payment can create new UTXOs for future use.
A sat/vB fee-rate estimate changes with demand and does not guarantee confirmation time. Check the total fee before signing, not just the suggested rate.
Your first successful transfer is the beginning. Think about how you will access the wallet in a few years if you lose the device or move home. A complete backup and an understandable plan also help when you cannot act for yourself.
Check that an authorized person can use the plan without your memory, while it still resists easy theft. Review security over time; ticking a chapter is not a certification.
Restricts device use according to its security model.
It does not recover the wallet or protect a disclosed Seed Phrase.Helps derive keys again. Full recovery may require a passphrase, format, derivation paths or Multisig information.
Disclosure may enable theft; Multisig still requires the necessary number of signatures.With BIP39, it changes the wallet derived from the same words.
Even a typo creates a valid different wallet. Back up the exact passphrase separately; it cannot be reset.Adds protection to an account at a service. A passkey or security key resists phishing better than a TOTP code that you type.
It does not protect the keys or backup of a wallet you manage yourself.complete words written by hand
durable material chosen for the threats
separate locations with controlled access
verified recovery under manufacturer instructions
through a photograph or screenshot
through email, ordinary cloud storage or notes
by sending them to supposed support
by entering them on an unverified website
01The device arrived with a preprinted Seed Phrase or a preset PIN.
02Supposed support contacted you first and wants recovery words, a 2FA code or remote access.
03Someone promises guaranteed returns, doubled BTC or a risk-free product.
04A website requests a Seed Phrase for synchronization, an upgrade or unlocking.
05An app offers a different network just because it is cheaper, without checking compatibility.
06The entire address does not match the one verified on a trusted device.
07You are under pressure or an unsolicited caller is dictating the steps.
08You are planning a large transfer without address verification, a small test and a usable backup.
Read the related chapter first and check that you understand the risk. A completed checklist is not a guarantee of the outcome.
Choose a small test amount whose total loss you can bear.
Verify the legal entity and current authorization for your country; confirm actual BTC withdrawals are available.
Create the account on a verified domain; use a unique password and secured email.
Where available, enable phishing-resistant authentication; store recovery codes securely and set withdrawal protection.
Check the price including the spread and all fees; try a small unleveraged spot purchase.
Choose a self-custody process you can manage and verify the device and application provenance.
Set up the new wallet yourself; use a newly generated backup and never words supplied by a seller.
Store the complete backup offline and verify it without erasing the only working wallet.
Create a receiving address and compare it in full through a trusted procedure.
Send a small test through the correct Bitcoin network; verify receipt and appropriate confirmations.
For any further transfer, check the address, network and fee again; keep records.
Prepare a recovery and inheritance plan without a single easily accessible document exposing every secret.
Do I need to buy a whole bitcoin? How does a wallet work, and what should I back up? Choose the topic you are dealing with right now. The guide will take you through the answer step by step, explain important limitations and link to sources and related Atlas entries.
No single party does. Developers publish software, miners propose blocks, businesses choose services and users decide which rules their nodes accept.
Read the guide →02No. The network records spendable outputs; the wallet manages the keys and data needed to control them.
Read the guide →03No. One bitcoin divides into 100 million satoshis, so you can buy a small fraction.
Read the guide →04Crediting can be quick, but the purchase may cost more or face a waiting period. Compare the final amount and withdrawal availability, not just deposit speed.
Read the guide →05With a correct self-custody wallet backup, funds can usually be recovered elsewhere. Without a backup, keys may be permanently lost.
Read the guide →06Yes, for receiving, but reusing it can reveal transaction links. Never share private keys or recovery words.
Read the guide →07Coins are not stored inside the device. A compatible recovery process can reconstruct the keys from the backup, provided you retained every required secret and configuration detail.
Read the guide →08It creates copies, metadata and exposure to networked devices. Offline physical backups are generally easier to reason about and audit.
Read the guide →09No legitimate support procedure needs your recovery words. Treat a request to send them or enter them in a web form as an attempt to obtain the secret.
Read the guide →10A photograph creates a digital copy exposed to the device, its backups and cloud storage. A safer starting point is a complete readable offline backup with carefully planned access.
Read the guide →11They do not change the issuance ceiling, but they can reduce the amount that is actually spendable. The protocol cannot reliably distinguish a lost key from a very patient holder.
Read the guide →12A miner can publish such a block, but nodes following the rules reject it. Hashrate cannot make an invalid coinbase reward valid.
Read the guide →13Its direct product is an easily verifiable proof tied to a specific block header. Freely reusing the work for another task could weaken that commitment or introduce shortcuts.
Read the guide →14Only temporarily between difficulty adjustments can blocks arrive faster. Retargeting brings the long-run issuance pace back toward the schedule.
Read the guide →15Channel opening and eventual settlement are on-chain. Individual intermediate balance updates normally remain off-chain unless a dispute or close requires publication.
Read the guide →16The recipient can usually treat a successfully fulfilled conditional payment as complete within the channel system. Final enforcement of a dispute still depends on Bitcoin and its confirmations.
Read the guide →17Dollar-cost averaging: regularly investing the same amount of money.
Read the guide →18No. The result still depends on bitcoin’s future price, costs and holding period.
Read the guide →19Yes, it is commonly classified that way. But the broad category does not explain Bitcoin’s specific rules or mean other systems share its properties.
Read the guide →20No. They differ in design, permissions, issuance, dependencies and risks. This comparison is neither an investment ranking nor a guarantee of returns from any of them.
Read the guide →Protocol, regulator and manufacturer documentation explains rules and specific procedures. A manufacturer link is not a rating or guarantee of its product; links are not affiliate links.