Stop Spam. Read Books.

Over 200 million CAPTCHAs are solved every day by people around the world. reCAPTCHA channels this human effort into helping to digitize books and newspapers. When you solve a reCAPTCHA, you help preserve literature by deciphering a word that was not readable by computers. Learn more.

reCAPTCHA started as a project of the School of Computer Science at Carnegie Mellon University.

Credits

• Luis von Ahn — executive producer.
• Ben Maurer — software engineer.
• Colin McMillen — software engineer.
• Mike Crawford — software engineer.
• David Abraham — software engineer.
• Edison Tan — software engineer.

Open Source

reCAPTCHA is mostly powered by open source software. We'd like to thank all open source developers for creating tools that help in developing applications such as ours, but especially the developers of:

• nginx — the blazing fast webserver that powers reCAPTCHA.
• Hadoop — Distributed programming made easy
• Thrift — an RPC framework that allows for easy versioning
• Python — much of reCAPTCHA is written in Python.

Everything Else

• This site was designed by Pomp and Clout