Livegrep is maintained by a Stripe developer and is used inside Stripe. It has a slick demo on the Linux source code at livegrep.com.
Sourcegraph is a good replacement for Livegrep for almost every organization.
- Instant, as-you-type search results
- Quick search filters to narrow by path, etc.
- No support for code navigation (code intelligence and/or ctags)
- Difficult to manage and scale (requires building custom infrastructure)
- Although it’s used heavily by a small number of companies, it’s maintained part-time by a single developer, so future trajectory is limited