The 3si company logo

CRM solution provider

Over 20 years serving the NFP sector

A proud UK based company, operating from Stoke-On-Trent


Privately owned, privately funded – by 3Si’s owner, directors

We have successfully been providing services to the not-for-profit sector since 1993, with our original CRM solution, Open Market Classic.

Our promise – No contractors, 3rd parties or overseas call centres

We are proud to be a UK based company who does not use 3rd parties or contractors to complete any part of your project work. All work is handled by employed members of 3Si staff, based in our Head Office in North Staffordshire – especially our Help Desk.

Privately owned, privately funded – by 3Si’s owner, directors

OM.‍Net, the successor to Open Market Classic first shipped as a modular, cohesive platform in 2007. OM.‍Net has evolved into a specialised multi-company CRM, with an iterative release cycle. These features enable your team to maintain complex distributions of independent organisations, with different financial accounts, from one underlying database within a robust computing platform.

The success story of the sector

Relationships deepen to achieve mutual growth


Our clients – maintaining relationships since the 90’s
OM.‍Net is the CRM solution of choice for The National Farmers Union (NFU), Trading Standards Institute (TSI), British Mensa, The British Gliding Association (BGA), The Association of Building Engineers (ABE), The Parent and Teacher Association UK (PTA-UK) and The British Printing Industries Federation (BPIF) to name but a few…

Our partnerships – our business relationships go beyond our clients

We have established a relationship for total service. By providing our clients with back office and self-service web tools, we've achieved much along the way, including becoming a long standing Microsoft provider, fostering relationships with PCA Predict (PostcodeAnywhere), Bottomline Technologies Inc. and partnering with Sage Pay.