Ogrim is influenced by ALTCHA. Taking a quick glance, Anubis is a similar solution with some differences of solving the same problem:

• Anubis sits between the target service and the reverse proxy, while Ogrim sits behind the target service.
• One Anubis instance is needed per service, while a single Ogrim instance can be used for multiple services.
• The target service does not need integration with Anubis. On the other hand, Ogrim and its services must be integrated to work.
• Anubis will block search engine indexers, affecting the SEO of the target service. This is not the case with Ogrim.