We just released the first stable versions of the npm packages:
1. @ton-api/client — a new autogenerating client for working with TonAPI, compatible with the @ton/core library.
2. @ton-api/ton-adapter — an adapter for integrating @ton-api/client with the @ton/ton and @ton/core libraries, enabling the use of TonAPI functionality while maintaining the existing code structure.

You can check out the example of gasless transactiosns implementation using these libraries: https://github.com/tonkeeper/tonapi-js/blob/main/examples/gasless.ts