Taler is free software implementing an open protocol. Anybody is welcome to inspect our code and integrate our reference implementation into their applications. Different components of Taler are being made available under different licenses. The Affero GPLv3+ is used for the Mint, the LGPLv3+ is used for reference code demonstrating integration with merchant platforms, and licenses like Apache/Mozilla/GPLv3+ are used for wallets and related customer-facing software. We are open for constructive suggestions for maximizing the adoption of this libre payment platform.
Taler is designed to work on the Internet. To ensure that Taler payments can work with restrictive network setups, Taler uses a RESTful protocol over HTTP or HTTPS. Taler's security does not depend upon the use of HTTPS, but obviously merchants may choose to offer HTTPS for consistency and because it generally is better for privacy compared to HTTP. Taler uses JSON to encode structure data, making it easy to integrate Taler with existing Web applications. Taler's protocol is documented in detail here.
Taler is currently primarily developed by a research team at Inria and TU Munich. However, contributions from anyone are welcome. Our Git repositories can be cloned using the Git and HTTP access methods against git.taler.net with the name of the respective repository. A list of public repositories can be found in our GitWeb.
In addition to this website, the documented code and the API documentation, we are in the process of preparing a comprehensive design document which will be published here soon.