The e-commerce giant Amazon. com unveiled its plans for the Kindle Development Kit Thursday morning, which will enable developers to develop "active content" for the Kindle platform, to take benefit of the e-reader's electronic ink display, Whispernet 3G technology.

The beta of the development kit will be released in February, Amazon said.

Two companies are building apps for the device: Handmark, which is developing an active Zagat guide, and Sonic Boom, which will design word games and puzzles.

The Seattle-based company claims it will look forward to welcoming software developers to build and upload programs that would be sold in the Kindle store later in the year.

The kit is revealed to include sample code, documentation, and the Kindle Simulator, which assists developers, set up and examines their content by simulating the 6-inch Kindle and 9.7-inch Kindle DX on Mac, PC, and Linux desktops.

Revenue from users of the apps would be divided, with 70% of the money going to the developer and 30% to Amazon, net of delivery fees of $0.15 per megabyte.

Mr. Herdener suggested he hoped that publishers of newspapers, magazines and textbooks would create active content for the Kindle. "Kindle really does offer a unique experience and has a vast audience of voracious readers", he said.