Company lists · Data refreshed November 2026

Top 22 Legacy system integration developers based in London, United Kingdom

Name: Legacy system integration developers based in London, United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Nov 6, 2026 88 companies tracked

RevenueBase identified 88 company matches for legacy system integration developers associated with London, United Kingdom as of November 2026 and tracks 2,339 professional contacts across them, including 980 with verified work emails. Across the United Kingdom, London is the largest hub for this category.

This list covers company matches for legacy system integration developers associated with London, United Kingdom, found by RevenueBase SmartSearch using the meaning of business descriptions in its company graph at Exact. Ranked by professionals tracked, largest first. Rows show recorded descriptions where available, Exact search membership and the snapshot date. Data refreshed November 6, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase SmartSearch, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list RevenueBase SmartSearch · Exact Recorded Nov 6, 2026 How this list was built

88Companies

2,339Contacts tracked

980Verified emails

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The 22 largest legacy system integration developers based in London, United Kingdom

Ranked by team size

Top 22 of 88 company matches for legacy system integration developers based in London, United Kingdom, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Nov 6, 2026. The RevenueBase SmartSearch column shows Exact match membership in this saved search. Click a contact count to view that company's people. Totals use company locations recorded by RevenueBase; the displayed preview is a smaller selection.
#	Company	RevenueBase SmartSearch	Headquarters	Employees	Contacts
1	Integrella	Exact match	London, United KingdomHQ recorded Nov 6, 2026	51-200	76 contacts →
	Exact match “Integrella is a specialist IT services company with extensive experience across UK sectors.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
2	Advisority	Exact match	London, United KingdomHQ recorded Nov 6, 2026	51-200	57 contacts →
	Exact match “We are the trusted IT integrator that specialises in making your work flow.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
3	Diegesis Limited	Exact match	London, United KingdomHQ recorded Nov 6, 2026	51-200	53 contacts →
	Exact match “Diegesis is a business technology and IT systems integration company that specialises in Decision Support Solutions.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
4	Pace Integration	Exact match	London, United KingdomHQ recorded Nov 6, 2026	51-200	48 contacts →
	Exact match “Pace Integration is a unique technology consultancy that solves your integration challenge – focused on enterprise systems integration strategy, architecture and design that is…” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
5	R3 Digital	Exact match	London, United KingdomHQ recorded Nov 6, 2026	11-50	42 contacts →
	Exact match “R3 Digital is a Systems Integrator and Salesforce Platinum (Summit) Consulting Partner that specialises in Health and Life Sciences.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
6	Camwood	Exact match	London, United KingdomHQ recorded Nov 6, 2026	51-200	36 contacts →
	Exact match “Camwood: Igniting Enterprise Innovation for 25 Years.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
7	Igxglobal	Exact match	London, United KingdomHQ recorded Nov 6, 2026	1,001-5,000	23 contacts →
	Exact match “IGXGlobal is a technology systems integrator at the forefront of digital transformation.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
8	Digitalworks	Exact match	London, United KingdomHQ recorded Nov 6, 2026	11-50	16 contacts →
	Exact match “Digital Works is a digital and software development company.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
9	Patharitech	Exact match	London, United KingdomHQ recorded Nov 6, 2026	1-10	12 contacts →
	Exact match “Specialized in Integration domain.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
10	Solid State Group	Exact match	London, United KingdomHQ recorded Nov 6, 2026	11-50	10 contacts →
	Exact match “For corporates, startups, consultants, and everything in between, we design and build new digital products, drag legacy technology up to date, and make all your systems work…” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
11	Adaptivity	Exact match	London, United KingdomHQ recorded Nov 6, 2026	11-50	10 contacts →
	Exact match “Adaptivity is a specialist systems integration consultancy.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
12	Sorint.Lab UK Limited	Exact match	London, United KingdomHQ recorded Nov 6, 2026	201-500	7 contacts →
	Exact match “We are an IT service company focused on Digital Transformation and System Integration solutions, providing services, consultancy and training.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
13	RSV Solutions	Exact match	London, United KingdomHQ recorded Nov 6, 2026	11-50	7 contacts →
	Exact match “RSV Solutions is a UK-based technology consulting and digital transformation company helping organisations modernise, secure and optimise their technology environments.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
14	R4apps Limited	Exact match	London, United KingdomHQ recorded Nov 6, 2026	11-50	7 contacts →
	Exact match “At r4apps, we are dedicated to helping companies overcome their digital challenges with ease.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
15	Renav Technologies	Exact match	London, United KingdomHQ recorded Nov 6, 2026	11-50	6 contacts →
	Exact match “At Renav, we help businesses move from fragmented systems to fully integrated digital platforms.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
16	Quadcorps LTD	Exact match	London, United KingdomHQ recorded Nov 6, 2026	11-50	6 contacts →
	Exact match “Your trusted partner for API and Integration Ecosystem transformations - Military precision, expertly executed."We believe that what is expected of your systems integrator is…” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
17	Alchemise	Exact match	London, United KingdomHQ recorded Nov 6, 2026	11-50	6 contacts →
	Exact match “At Alchemise, we transform complexity into clarity.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
18	Shapecast	Exact match	London, United KingdomHQ recorded Nov 6, 2026	11-50	5 contacts →
	Exact match “We help organisations to radically simplify and modernise their IT and business systems using a highly successful, proven methodology that has helped transform some of the world's…” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
19	Thames Systems	Exact match	London, United KingdomHQ recorded Nov 6, 2026	11-50	4 contacts →
	Exact match “We provide technology consulting, software development and systems integration for a range of clients and industries.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
20	Quartzbyte	Exact match	London, United KingdomHQ recorded Nov 6, 2026	1-10	4 contacts →
	Exact match “QuartzByte Ltd is a London-based technology partner helping businesses simplify complexity and achieve sustainable growth through digital innovation.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
21	I15 Limited	Exact match	London, United KingdomHQ recorded Nov 6, 2026	1-10	3 contacts →
	Exact match “i15 is a consultancy, and solutions partner, founded by a dedicated group of IT professionals with a collective 80+ year track record of successfully designing, engineering…” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
22	Pasilda	Exact match	London, United KingdomHQ recorded Nov 6, 2026	1-10	2 contacts →
	Exact match “Pasilda is a London based software and web development business with a focus on systems consulting.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase

RevenueBase SmartSearch

Describe a niche business in your own words. RevenueBase SmartSearch compares the meaning of your description with company business descriptions compiled in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit.

This list uses Exact for “legacy system integration developers”. Each Exact match badge shows membership in that saved search; it is not an individual similarity score or a service-quality rating. Recorded descriptions are shown where available.

Showing 22 of 88 legacy system integration developers based in London, United Kingdom

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Legacy system integration developers based in London, United Kingdom at a glance

As of Nov 6, 2026

41.9%Verified-email coverage

26.6Average contacts per company

11-50Median size (employees)

Nov 6, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

501-1,000

1,001-5,000

Email recency for this list is measured across the whole United Kingdom list rather than for London, so it is reported there. Company counts and contact totals on this page are exact for London, over 88 companies.

How this list was built

The recorded descriptions help you assess these company matches. Check a company’s website for its current services and locations.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase SmartSearch, the natural-language company search available to every RevenueBase user.
What qualifies: Company records associated with London, United Kingdom whose business descriptions match “legacy system integration developers” by meaning at the Exact setting. Descriptions are compiled in the RevenueBase company graph from public websites, profiles and company information where available; they are not guaranteed quotations from the company's website.
RevenueBase SmartSearch: Describe a niche company in your own words to find businesses by meaning. Exact, Similar, Related and Broad control the breadth of RevenueBase SmartSearch. This saved list uses Exact. Each row's Exact match badge shows inclusion in that search, not an individual score or a service-quality judgment.
Public preview: The public preview omits records without a verified work email. Where headquarters information is recorded, preview rows are also filtered to this page’s location. Dataset totals and geographic summaries describe the full matched records before these preview filters.
Match quality: RevenueBase's August 25, 2026 study assessed 4,198 description/company pairs across matching settings. The publisher reports 86% good or better at Exact. This evaluates the method across queries; it does not audit this individual list. Recorded company descriptions, where available, help you judge each match yourself. Read the full methodology: how the lists are built and what the study measures.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every displayed company carries at least one verified work email. RevenueBase tracks 980 professional contacts with verified work emails across the full matched dataset. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on November 6, 2026. Lists refresh periodically as the graph is re-checked.
Record context: Company records and descriptions can change. Check the company's website for its current services and locations.

Frequently asked

What is RevenueBase SmartSearch?

RevenueBase SmartSearch finds niche companies by the meaning of their business descriptions in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit your description. This list uses Exact for “legacy system integration developers”; each Exact match badge shows search membership, not an individual similarity or quality score.

How many legacy system integration developers are there based in London, United Kingdom?

RevenueBase identified 88 company matches for legacy system integration developers associated with London, United Kingdom as of November 2026, using the meaning of business descriptions at Exact. This is the recorded matched set in the RevenueBase company graph.

What is the largest company on this list?

Integrella tops the displayed preview by professional contacts tracked in RevenueBase. Recorded headquarters appear in the company rows.

Which city in the United Kingdom has the most legacy system integration developers?

London leads the United Kingdom with 88 company records, followed by Leeds (8) and Manchester (8).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work limited free results with 500 credits to start. Upgrading provides access to the 980 professional contacts with verified work emails tracked across these 88 companies; direct dials are available where recorded.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on November 6, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase SmartSearch, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.