San Francisco start-up Mashery has raised another round of capital to help Web companies open their platforms so that developers can build applications on top of them.

By releasing an API, or Application Programming Interface, a company can allow “mashups” of its data, and gain reach across the Web. Google did this with Google Maps, for example, mixing them with everything from housing to restaurant information. Now all sorts of businesses — banks for example — are doing this with more sensitive information, some of it requiring significant management of terms and conditions.

The amount was undisclosed, but we’ve heard it was less than $5 million.

The latest funding comes from the Formative Ventures and The Accelerator Group, as well as additional funding from First Round Capital. We first reported about the company here.