Grockit, a San Francisco-based educational startup, has raised an additional $8 million, led by Integral Capital Partners with previous investor Benchmark Capital participating.

The company has been working on a product since last year, but has managed to keep the details close to its chest. Last July, we reported that it had raised $2.7 million from Benchmark.

Grockit was started by Farbood Nivi, a former exam prep teacher for Kaplan, a major test maker for all levels of the educational system.