MEW Offline is available for users who want to generate wallets or sign transactions on an offline computer, to keep their sensitive key information from interacting with the internet.
The MEW web interface can be downloaded from our Github and run locally on an offline computer. Transactions are generated with MEW’s Offline Helper on an online computer and signed with MEW Offline on a second offline computer.
This is the method we recommend for accessing wallets with software methods like keystore file, mnemonic phrase, and private key. We do NOT recommend software access while connected to the internet as this increases the risk of your wallet being compromised.
You can also use MEW offline to create a paper wallet.
If you’re still using Software methods, consider getting a more secure wallet like MEW wallet or Enkrypt. See the links below for more information:
Downloading MEW offline
Before downloading MEW offline, make sure that you’re using the computer that is online. To start downloading:
Download the Offline zip folder from the latest release.
Note: If you want to use MEW offline to send a transaction from a software wallet, or to try canceling/replacing transaction by manually adjusting the nonce, please download that Offline.zip version of the files. To run MEW the same way as you do in the browser, but from your desktop, please download the Hash.zip version.
When it’s done downloading, open and unzip the folder. You should then see the files shown in the image below.
Make sure you put all of the offline files on a usb/ flash drive and transfer them to the offline computer.
Nice! You just downloaded the latest MEW offline file.
Sending an Offline transaction
When using the Offline helper on MEW, you should be using the computer that is connected to the internet. When completing an Offline transaction, it's important that you enter the correct details to avoid any issues so make sure to double-check the addresses entered.
Offline transactions require gas, so before completing a transaction make sure that the sending wallet has a sufficient amount of crypto to cover the cost of gas.
For an explanation of how that works, feel free to refer to the article below:
>> What is Gas?
Generating your Offline transaction:
On the online computer, head to our website at www.myetherwallet.com and scroll down to the bottom of the page.
Then click on ‘Offline Helper’.
Select the network that you want to send from then click ‘Next’.
Leave it on ‘ETH’ if you are using Ether or ERC20 tokens.
Fill in the address you are sending from, and our interface will generate a gas price and nonce for your transaction, along with other details.
Make a note of your nonce, export the transaction JSON file, and move this file onto a USB.
Keep this window open on your online computer until you're ready to come back to it in a later step.
Plug the USB into the Offline computer and access the offline version of MEW. This is done by opening the ‘index.html’ file from the unzipped offline package in a browser, preferably Chrome.
Access your wallet as you would normally, and choose ‘Send Offline’ from the menu to the left.
Keep in mind that this is made for the software methods specifically such as a keystore file, private key, or mnemonic phrase.
Select the crypto that you’re sending from the dropdown menu then enter the amount being sent, as well as the address that it’s being sent to.
If you’re sending tokens other than ETH, extra data may cause you to need a higher gas limit. To avoid issues, we recommended setting the Gas limit to 100,000. All unused gas will be refunded to the sending wallet. Check out the ‘What is Gas’ article for more of a breakdown of how gas works.
Keep in mind that you won't see balances of ETH or tokens while using MEW offline. If you’re in doubt about how much you can send, make sure to check the wallet address on Etherscan back on the online computer.
Upload your JSON file from the connected USB.
Alternatively, you can manually fill in your nonce, transaction details, and the address you are sending to, as well as other relevant data from the information given to you by the Offline Helper in Step 4.
Click ‘Generate Transaction’, then copy the long string that says ‘Signed Transaction’ and paste it into a text file, or download a new JSON file holding your signed transaction’s details. Drag this text file or JSON file into your USB for the final step in the process.
Signing and Sending Offline transactions
After generating your transaction,
Head back to MyEtherWallet.com and the open Offline Helper on your online computer.
Paste in your signed transaction, or import the new JSON file you just received, then press ‘Confirm and Send’.
You should now be seeing your transaction status. Review the details of your transaction then press ‘Close’.
You’re done! Your transaction will show on an Ethereum blockchain explorer once it’s been verified. It can be searched using the transaction hash shown at the end of the process.
If you experience any issues using MEW offline, please contact our Support team at email@example.com for further assistance.