Electrum-GRS mobile wallet allows you to send and receive Groestlcoins on your device without syncing the blockchain. When using this app, please store your secret phrase and email them to yourself! Then your coins can be retrieved even if you loose your phone. Furthermore, this puts the user in total control of their funds at any given time.

Electrum-GRS mobile implementations:
BIP-0032 to implement a hierarchical deterministic wallet
BIP-0039 to implement a mnemonic code of mnemonic sentence for the generation of deterministic wallets (process for turning in into a BIP-0032 seed)

Changelog Groestlcoin Electrum GRS v1.5.29:
• Rebranded to Groestlcoinomi
• Updated Testnet logo

Changelog Groestlcoin Electrum GRS v1.5.28:
• Added testnet support and ability to switch between mainnet and testnet
• Added support to receive from non native segwit address
• Added more electrum-grs servers

Changelog Groestlcoin Electrum GRS v1.5.25:
• Improved UI for setting a BIP39 passphrase
• Fixed memory leak when restoring a wallet
• Fixed crashes on some devices
• Possibility to sign and verify messages
• Account details screen to view the public key
• Some UI optimizations
• Bug fixes
• Increase the default size of the recovery phrase
• Can set an amount in receive screen
• Small optimizations when handling the QR code and transactions
• Added ability to spend own unconfirmed change funds
• Support payment URIs requests from browsers and other apps

• Exchange rates for various national currencies
• Manual receiving address management (enable in settings)
• Wallet only needs to be backed up once, on initial creation.
• Wallet backup consists of simple list of 12 common words (BIP-0039).
• Empty the wallet with 1 click
• Automatic connectivity management with fast reconnects and detection of network change
• Password protect your recovery phrase
• Top security - Electrum-grs uses bank grade technology. Your money is kept safe by guaranteeing that your private keys will never leave your gadget. The user has absolute control
• Warning if there are no connections to the Electrum-GRS servers
• Click on any addresses to edit the label or copy it
• Support payment URIs requests from browsers and other apps

Source code:
Android: - Groestlcoin Java Library (for the Android App and possibly other software) - GroestlCoinomi Android

BlackBerry: - Groestlcoin Java Library (for the Blackberry App and possibly other software) - GroestlCoinomi Blackberry