Several people helped during SQLgrey development:

Dan Faerch:
- Database clustering (1.7.4)
- Regex based Discrimination (1.7.4)
- Customizable reject_code (1.7.4)
- sqlgrey maintainer for release 1.7.4
(Is now a regular developer of sqlgrey. No need to list more contributions here)

Othmar Truniger:
- corrected sqlgrey-logstats.pl weekly stats (1.7.4)

Corey Sklenicka:
- non standard DBMS listening port support (1.7.4)

Jeff Rice:
- deVERP tuning (especially for bounce/notify messages) (1.7.2),

Michael Storz:
- deVERP tuning replace recipients in sender address (1.7.2 and 1.7.3)

Michel Bouissou:
- source IP throttling (tarpitting) (1.7.0),
- better connect cleanup when moving entries in AWL (1.7.0),
- new 'smart' greylisting algorithm, replacing previous one (1.5.1),
- portability fixes in update_sqlgrey_config (1.4.5)
- configurable return code (1.4.5)
- deVERP and SRS tuning (1.4.5)

Rene Joergensen:
- better cleanup logging (1.4.2)

Øystein Viggen:
- fix for startup warning messages (1.4.1)
- found an SQL injection vulnerability (fixed in 1.4.0)

Derek Battams:
- ideas for different greylisting algorithms (implemented in 1.3.6)

Klaus Alexander Seistrup:
- idea for SQLite support (implemented in 1.1.0)

Numerous others helped with great ideas or bug reports.