Company lists · Data refreshed September 2026
Top 25 Legacy system integration developers worldwide
RevenueBase identified 89 legacy system integration developers worldwide as of September 2026 and tracks 602 professional contacts across them, including 152 with verified work emails. The United States is the largest market and Dublin the largest hub.
This list covers legacy system integration developers worldwide, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 20, 2026. Country and city lists for legacy system integration developers follow the table.
Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, 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.
The 25 largest legacy system integration developers worldwide
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 47 contacts → | ||||
Indirect evidence “Our focus is to build agile solutions across devices and bundled with a middleware that enables our clients to expose multiple access points to their LOB Applications.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 2 | 32 contacts → | ||||
Partial evidence “Since 1995 Flynet have been building some of the industry's most sophisticated web based solutions for Mainframe, Unix, IBM i, VMS, VAX and MultiValue systems.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 3 | 29 contacts → | ||||
Partial evidence “TechBerry is a software product company that offers a low code integration platform, which enables AS400 enterprise applications such as core banking and insurance to connect to…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 4 | 21 contacts → | ||||
Strong evidence “Collabrium Systems, LLC provides systems integration services that include design, development, testing, implementation and support of business applications.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 5 | 20 contacts → | ||||
Indirect evidence “At Eradani, we understand the wisdom of the ancient saying that you cannot know where you are going if you do not understand where you have been.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 6 | 15 contacts → | ||||
Partial evidence “En integration märks inte när den fungerar.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 7 | 14 contacts → | ||||
Indirect evidence “Strategy, Architecture, Development and Testing are key components of our business that help us deliver cost effective and flexible solutions.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 8 | 14 contacts → | ||||
Strong evidence “Als Systeem Integratie en Enterprise Application Integration ( EAI ) specialist is Response BV toonaangevend binnen de Benelux.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 9 | 14 contacts → | ||||
Strong evidence “Acqua, brings an innovative and proven approach to how organizations design, build, and manage their integrations and APIs so they can modernize legacy applications, move to the…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 10 | 13 contacts → | ||||
Partial evidence “At RDM Infinity, we work with the system you have to create the solution you need.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 11 | 13 contacts → | ||||
Indirect evidence “Oltre 30 anni di esperienza in verticalizzazione di sistemi rendono GSA il partner ideale a cui affidare la progettazione e la realizzazione di integrazioni software atte a…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 12 | 10 contacts → | ||||
Partial evidence “Go4IT Solutions, somos una spin-off de Tecnalia dedicada a la modernización automática de aplicaciones legacy.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 13 | 10 contacts → | ||||
Strong evidence “With 20 years and over 120 successful migration projects in Brazil and abroad, Xseed has experience and skill in legacy systems migrations from mainframes to several open…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 14 | 9 contacts → | ||||
Indirect evidence “Our world is diverse and technology and data are the same.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 15 | 9 contacts → | ||||
Strong evidence “We help our clients build, manage and scale the world’s best application integration platforms solving the most complex integration challenges.*Proud Talend System Integrator…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 16 | 8 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 17 | 8 contacts → | ||||
Indirect evidence “Durante más de 10 años hemos trabajado en la evolución de sistemas empresariales críticos en el sector financiero.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 18 | 7 contacts → | ||||
Partial evidence “itheis is a major actor in the IBM i iSeries System i modernization market.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 19 | 6 contacts → | ||||
Partial evidence “A team of experienced developers that has been working together for almost 5 years.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 20 | 5 contacts → | ||||
Partial evidence “The DARQ Room is a development firm that specializes in streamlining and connecting disparate software systems.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 21 | 4 contacts → | ||||
Strong evidence “Joint Technologies is an Independent Software Vendor and System integrator started in It has developed the capabilities to integrate software and third-party products in order to…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 22 | 4 contacts → | ||||
Indirect evidence “ClientServ Technologies helps businesses untangle their IT, clearly, efficiently, and without the headaches.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 23 | 4 contacts → | ||||
Strong evidence “Linknow IO provides system integration as a service.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 24 | 4 contacts → | ||||
Strong evidence “At middleware technologies®, we specialise in empowering enterprises to unlock the full potential of their legacy systems through seamless integration and modernisation.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 25 | 4 contacts → | ||||
Partial evidence “Schnittstellen, aber beherrschbar: Wir entwickeln und betreiben Integrationen auf Basis einer modernen Middleware-Architektur.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: legacy system integration developers. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.
- Strong evidence
- The company's own public description of its business names legacy system integration developers.
- Partial evidence
- Its own public description names part of legacy system integration developers, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name legacy system integration developers. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.
RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.
Showing 25 of 89 legacy system integration developers worldwide
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Legacy system integration developers worldwide at a glance
As of Sep 20, 2026Companies by employee count
Email recency is reported on each country list linked below.
How this list was built
Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among legacy system integration developers, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.
- Source
- The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
- Coverage
- Every country. Country and city lists for legacy system integration developers are linked below.
- What qualifies
- Companies worldwide whose own description of what they do matches “legacy system integration developers”. Matching reads each company's description, not its industry code or its name.
- RevenueBase Smart Search
- RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names legacy system integration developers), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
- What we exclude
- Companies whose own description does not clearly place them among legacy system integration developers, and records with no verified work email.
- Match quality
- In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
- 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 listed company carries at least one verified work email, 152 across the full list. 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 September 20, 2026. Lists refresh periodically as the graph is re-checked.
- Corrections
- Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.
Legacy system integration developers by location
1 lists · largest firstEvery Legacy system integration developers list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.
Countries
Frequently asked
What is RevenueBase Smart Search?
RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names legacy system integration developers, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.
How many legacy system integration developers are there worldwide?
RevenueBase identified 89 legacy system integration developers worldwide as of September 2026, matched on each company's own description of what it does rather than its industry code.
What is the largest company on this list?
TTH Consulting Services, headquartered in Turbhe, tops this list with the largest team on record.
Which country has the most legacy system integration developers?
The United States leads with 25 companies. Every legacy system integration developers list by country and city is linked on this page.
Which city has the most legacy system integration developers?
Dublin leads with 3 headquartered companies, followed by Aix En Provence (1) and Austin (1).
How do I get contact information for these companies?
A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 152 verified decision-maker contacts tracked across these 89 companies.
How current is this list?
The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 20, 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 Smart Search, 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.