Olesia.

Enter your PIN

Your wallet is stored encrypted on this device — the PIN decrypts it in memory.

scrypt + XChaCha20-Poly1305 · the seed itself never touches disk

Confirm

testnet4
Olesia.

Learn Bitcoin by doing — a real wallet on practice networks where mistakes cost nothing.

Bitcoin has several chains sharing the same rules. Testnet3/4 and Signet use free, worthless coins for practice. Mainnet is real money — learn on a testnet first.

Storing meaningful funds? Generate fully offline with the cold generator and use this app watch-only.

Non-custodial · open source · verify everything · learn the basics

Create your wallet

Step 1 of 4 — randomness

Your wallet is a giant secret number. Olesia always draws 256 bits from your device's cryptographic random generator — that alone is unguessable (more possible keys than atoms in the universe).

＋ Add your own entropy (optional) ▾

Write these down

Step 2 of 4 — your seed phrase

These 24 words are your wallet — anyone who has them controls the coins, and there is no reset. Write them on paper, in order. Never screenshot or cloud-sync them.

Prove it 😉

Step 3 of 4 — tap the right word for each position

Backup confirmed ✓

Step 4 of 4 — how should this device remember your wallet?

Saved encrypted behind a PIN (scrypt + XChaCha20-Poly1305). The plaintext seed never touches disk — your PIN decrypts it in memory each time.

Import a wallet

Paste a seed phrase (12/24 words) — or an account xpub to watch a balance without spend power.

Your wallet is its words (BIP-39) — anyone with them controls the coins. An xpub can watch a balance but cannot spend: the safe way to use a cold wallet online. Private-key (WIF) and encrypted-file import are coming next.

Made your seed with the cold generator? Pasting the words here makes it a hot wallet — fine for practice/small amounts. For real funds, import its xpub instead and sign offline (Settings → Air-gap).

TOTAL BALANCE
—tBTC

History

Refresh
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Accounts

One seed → every Bitcoin address type. Tap any to receive, send, or learn what makes it different.

Account

· about ▾

derivation path ?

The route from your seed to this account's key: m / purpose' / coin' / account' / chain / index. The first number is the script-type standard (44'=legacy, 49'=nested, 84'=SegWit, 86'=Taproot); coin is 0' for mainnet, 1' for test networks. Same seed + same path = same keys, in any BIP-compliant wallet — that's why your seed restores anywhere.
address QR

Scan or copy to receive. Need coins? Free testnet coins →

BALANCE
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History

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Send

From — · —

A transaction spends your UTXOs (coins) as inputs and creates outputs: one to the recipient, and usually one back to you as change. Amounts are in satoshis — 100,000,000 sats = 1 BTC.
Add a message · OP_RETURN What's this? ▾
A tiny permanent note (~80 bytes) written into Bitcoin's public record. It carries no coins and can never be spent.

Genuine uses: proving a document existed at a point in time, notarising, attribution, a personal message or memorial.

The famous one: Satoshi wrote a newspaper headline — "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks" — into the very first block. OP_RETURN is today's tidy way to leave your own mark like that.

Where we stand: people disagree about what data belongs on Bitcoin. Olesia is neutral — it's part of the protocol, so it's here, explained, for you to use thoughtfully. (No NFTs or inscriptions.)
Miners include transactions that pay them, priced in sat/vB. Auto asks the network for a live estimate — the safe default. Higher = confirms faster.

Learn Bitcoin

Every concept in plain English — then try it for real. Progress saves on this device.

0 of 9

Want the long version with diagrams? olesia.io/learn →

Settings

Wallet

🌐Network
➕Create or import another walletcloses the current one first›
🔎Account xpub (SegWit)share balances without spend power›

Security

🔒Keep wallet on this devicenot saved — seed lives in this tab only›
📜Backup seed phraseview your words — PIN required›
🚪Lock nowclears the seed from memory
Anyone who sees these words controls the coins. Make sure nobody is watching your screen, and never screenshot them — write them on paper.

Saves your seed encrypted (scrypt + XChaCha20-Poly1305 — the cold generator's own crypto). Plaintext never touches disk; your PIN decrypts it in memory. A weak PIN on a compromised device is still a risk — real money belongs in cold storage.

Advanced

✈️Air-gap / PSBT toolsthe mainnet-safe path (SegWit account)›

Watch-only online: Build unsigned (uses the Send screen's fields) → sign offline → Broadcast here. The seed never needs to be online.

About

✅Verify this buildreproducible — check the hash yourself↗
🐙Source & auditsgithub.com/testnetbtc/BTC_Wallet↗
🏷️Version2.1.0

Balances/broadcast via mempool.space (mainnet broadcast via api.olesia.io). No analytics, no server-side storage. Signing with @scure/btc-signer, in your browser.