Question: I need a solution that integrates cryptocurrency transactions with a messaging platform, with no transaction fees - do you know of any options?

If you want a service that combines cryptocurrency payments with a messaging service and has no transaction fees, 0x is worth a look. It provides a range of APIs to ease the creation of financial apps on crypto foundations. The Gasless API is designed for transactions with no friction, the Swap API for trading cryptocurrencies, and the Tx History API for users' trading history. 0x has enterprise-scale DEX infrastructure and audited and secure smart contracts, so it's a good choice if you want to add cryptocurrency payments to a messaging service.

Another option is CoinSender, which automates crypto/fiat accounting, tax and payroll for web3 sector companies and individuals. It integrates with wallets, supports smart contracts and multiple blockchains, and offers a full suite of cryptocurrency transaction and financial services. CoinSender is relatively inexpensive and fast, with transactions costing less and taking less time than manual on-chain processes.

If you want a service that spans a wider communication experience, Sendbird is a communications API platform that spans chat, SMS, WhatsApp, voice and video across many communication channels. It doesn't have a cryptocurrency transaction service, but it has a powerful chat infrastructure that you can combine with other services to offer a full messaging service with real-time communications.

You might also want to look at CryptoDo, a no-code platform that lets you create and deploy web3 apps and smart contracts in five minutes. It supports a range of services, including ERC-20, ICO, NFT, DAO and more. CryptoDo is easy to use and relatively inexpensive, which could be good if you want to add cryptocurrency transactions to your messaging service without having to hire a programming expert.