Littlefish has apologised after ‘reluctantly’ delaying an open evening at Steel City House on West Street on Thursday.
A spokesman added: “We are sorry for any inconvenience this may cause and of course we will be re-scheduling at a later date.”
The company announced in January it was opening an office in Sheffield and planned to hire 150 people.
It has taken a floor in Steel City House and organised an event this week to celebrate.
The Nottingham-based firm has grown from £6m turnover to £30m in the last three years.
High profile clients include the Houses of Parliament, where it has 8,500 users. It also serves local authorities which have IT in-house.