Olesia.

Last updated: 12 August 2026

The short version: Olesia collects nothing about you. No account, no email, no name, no analytics, no advertising, no tracking, no cookies. Your seed phrase and private keys are created on your device, stay on your device, and are never sent anywhere — not to us, not to anyone. We could not access your wallet if we wanted to, and we could not hand it over if we were asked.

Who we are

Olesia is a free, open-source, non-custodial Bitcoin wallet built for learning. “Non-custodial” means we never hold your coins or your keys — only you do. The entire source code is public at github.com/testnetbtc/BTC_Wallet, so every claim on this page can be independently verified rather than taken on trust.

What we do not collect

No accounts, sign-ups, usernames, emails or phone numbers
No names, addresses or identity documents (no KYC)
No analytics, telemetry, crash reporting or usage statistics
No advertising identifiers, no third-party trackers, no cookies
No seed phrases, private keys, PINs or passphrases — ever

What stays on your device

Everything that matters. Olesia stores a small amount of data in your browser or app storage, on your device only. It is never transmitted.

Stored item	What it is
`olesia:vault`	Your seed phrase, encrypted with your PIN (scrypt + XChaCha20-Poly1305). Without your PIN it is unreadable — including by us.
`olesia:pinlen`	The length of your PIN (never the PIN), so the keypad knows when to submit.
`olesia:label:…`	Any nicknames you give your own accounts.
`olesia:learn`	Which lessons you have read.

You can erase all of it at any time with Settings → Forget saved wallet, or by clearing site data / deleting the app. We hold no copy, so there is nothing for you to ask us to delete.

What leaves your device, and why

A wallet has to talk to the Bitcoin network to show balances and broadcast payments. Olesia contacts only these services, and only for that purpose:

Service	What is sent	Why
mempool.space third party	Your Bitcoin addresses (to look up balances and history) and signed transactions you choose to broadcast.	To show your balance and send payments. Governed by their own privacy policy.
blockstream.info third party	The same, used as a fallback when mempool.space is unavailable.	Reliability. Governed by their own privacy policy.
api.olesia.io ours	Only if you use the testnet faucet: the practice address you paste, and your IP address.	To send you free practice coins and stop one person draining the faucet.

Please understand this properly. Bitcoin is a public ledger, and looking up a balance means telling someone which addresses you care about. Those third-party explorers can see your IP address alongside the addresses you query — that is true of almost every wallet, not just Olesia. If that matters to you, the answer is to run your own node, and we would rather teach you that than pretend the problem away.

The faucet, specifically

Our faucet gives away worthless testnet coins. To stop abuse it keeps a short-lived, in-memory record of recent claim IPs and addresses — a sliding window that is discarded automatically. It is not written to a database, not profiled, and not shared. If the Cloudflare Turnstile human check is enabled, your IP is shared with Cloudflare purely to verify you are not a bot, under their privacy policy.

Children

Olesia is not directed at children under 13, and since we collect no personal data, we do not knowingly collect anything from them.

Your rights (UK GDPR)

Rights of access, correction, erasure and portability all apply to personal data a company holds about you. We hold none, so in practice there is nothing to request — your data is already entirely in your own hands. If you believe otherwise, contact us and we will investigate promptly. You may also complain to the UK Information Commissioner's Office (ico.org.uk).

Changes

If this policy changes we will update the date above and publish the change in the public repository, where the full history is visible to anyone.

Contact

Questions about privacy? Open an issue at our public GitHub repository — asking in the open means the answer helps everyone, and you can see it was answered.

← Back to Olesia · Non-custodial. Open source. Your keys, your coins.