Apply the EIP-55 mixed-case checksum to an Ethereum address, check whether one already has it right, and show it in lowercase and uppercase.
Ethereum Address Tools needs nothing from a server once the page has loaded. Leave it open on a train with no signal and it carries on.
Your input goes into a function and the result comes back out, both inside this tab. There is no round trip and no third party in the middle.
You will find it under Blockchain, alongside 6 other tools for the same sort of job.
Runs in this tab, so nothing you type is uploaded.
0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed
Checksum address: 0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed Lowercase address: 0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed Uppercase address: 0x5AAEB6053F3E94C9B9A09F33669435E7EF1BEAED Is eip55 valid: yes Reason: All one case, so there is no checksum claim to check.
0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed
Checksum address: 0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed Lowercase address: 0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed Uppercase address: 0x5AAEB6053F3E94C9B9A09F33669435E7EF1BEAED Is eip55 valid: yes Reason: Matches the EIP-55 checksum.
Yes. It is JavaScript running in this tab, so once the page has loaded it needs nothing further from the network. Put the machine in flight mode and it carries on. Nothing you do here is sent anywhere, because there is nowhere for it to go.
No. Reload the page and it starts from nothing. There is no account, no saved state and no cookie holding your last session. That is a deliberate trade: it cannot lose your data because it never keeps any.
Timing comes from performance.now(), the high resolution clock the browser provides, rather than from setInterval, which drifts by a few milliseconds every tick and compounds over minutes. What can still shift things is the browser throttling a tab in the background, so leave it visible if the timing matters.
Where a sound makes sense, it is generated with the Web Audio API rather than loaded as a file, so there is nothing to download and nothing to block. Browsers refuse to start audio until you have interacted with the page, which is why the first press is what switches it on.
Yes. The controls are sized for touch and the layout collapses to one column on a narrow screen. Bear in mind that a phone locking its screen will suspend the page, and timing stops with it.