Top 10 custom software development companies in London

It depends on the scope, the size of the team and how long the work runs, so be wary of anyone who quotes a price before they understand your requirements. Smaller studios usually give a fixed price for a defined first release after a discovery phase; larger consultancies more often charge day rates for a team. Ask each company for the cost of the first release and of support after launch, so you can compare like with like.

Large consultancies bring several teams, specialist skills and experience of big programmes, which suits government departments and large enterprises. Smaller studios tend to put senior people on your project and move quickly, which suits a growing business building its first platform. The right choice depends on the size of the job and how much of the work your own team will take on.

It depends on the scope. Most companies split the work into a first release with what you need to launch, then add features in stages. That puts working software in front of your users sooner and spreads the cost. Ask for a timeline for the first release rather than for everything at once.

Agree it in the contract before work starts. You should own the source code, the database and the documentation, and hosting and third-party accounts should be in your organisation’s name, so you’re free to change supplier later.

When you’re paying for several tools that don’t talk to each other, relying on spreadsheets and manual steps, or bending your process to fit someone else’s product. Custom software is built around your process instead, and you can change it as the business changes.

Several of them work mainly in the public sector. Unboxed lists itself on the government’s G-Cloud 15 and Digital Outcomes and Specialists 7 frameworks, and Softwire is a Crown Commercial Service supplier. Check a company’s current framework listings with the Crown Commercial Service before you start a procurement.

We included companies that build bespoke software, are based in London or have a staffed London office, and show recent work. Exibify is first because we publish this article. The other nine are ordered by the breadth and scale of their work, not by quality, and none of them paid to be included. Details were checked on 4 November 2026.