Company lists · Data refreshed September 2026
Top 25 Inside sales call centers worldwide
RevenueBase identified 2,298 inside sales call centers worldwide as of September 2026 and tracks 48,072 professional contacts across them, including 3,298 with verified work emails. The United States is the largest market and Rawalpindi the largest hub.
This list covers inside sales call centers 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 28, 2026. Country and city lists for inside sales call centers 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 inside sales call centers worldwide
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 2,774 contacts → | ||||
Strong evidence “Advanced Call Center Technologies, LLC (ACT) is a premier provider of domestic (USA), near shore and far shore outsourced call center services to the financial services, mortgage…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 2 | 1,198 contacts → | ||||
Strong evidence “The Office Gurus (TOG) is a global call center and business process outsource provider of customer care, telemarketing, lead generation, appointment setting, order entry, accounts…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 3 | 1,058 contacts → | ||||
Indirect evidence “Em breve uma nova página da BTCC Conexão Cliente.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 4 | 978 contacts → | ||||
Indirect evidence “Expert de la relation client depuis 1996, b2s est le N°1 de l’externalisation de votre relation client en qualité délivrée.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 5 | 902 contacts → | ||||
Strong evidence “Our Company Inktel is a leading business process outsourcer that specializes in creating personalized call center solutions which enable our clients to increase market share…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 6 | 883 contacts → | ||||
Indirect evidence “If you are interested in growing your business or increasing efficiency, AnswerNet has the expertise, technology, and people to help you take your company to new heights!” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 7 | 542 contacts → | ||||
Indirect evidence “R683 million in annualised premium income generated for our clients, R70 billion in insurance cover sold to almost 2 million South African people, by 850 previously disadvantaged…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 8 | 474 contacts → | ||||
Indirect evidence “A HOME AGENT S.A.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 9 | 447 contacts → | ||||
Strong evidence “Proper Business solutions is offering a comprehensive suite of customer care call center services, outbound and lead generation, back-office and data processing solutions to…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 10 | 428 contacts → | ||||
Partial evidence “Alliance is a domestically operated, internationally recognized professional contact center specializing in lead generation and appointment setting.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 11 | 393 contacts → | ||||
Indirect evidence “Touchstone Communications was built in 2002 on the philosophy of hiring educated, motivated talent and then providing them with the best training and management to achieve our…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 12 | 376 contacts → | ||||
Strong evidence “A Cobmax é uma Sales Center com inteligência em vendas, fruto de metodologia própria, testada e aprovada em 11 anos de experiência.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 13 | 354 contacts → | ||||
Partial evidence “For over 35 years, The Connection has made a name for ourselves becoming one of the top industry partners to Fortune 500 companies looking to outsource their contact center…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 14 | 346 contacts → | ||||
Strong evidence “As a distinguished global leader in call center outsourcing, OnBrand24 takes pride in its 30-year legacy of delivering exceptional inbound and outbound call center services across…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 15 | 338 contacts → | ||||
Strong evidence “With more than 900 employees, PhoneAct is an ISO 9001/2008 certified offshore call center service provider.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 16 | 307 contacts → | ||||
Strong evidence “TeleDirect provides 24/7 U.S-based call center and answering services for organizations that cannot afford to miss important calls.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 17 | 306 contacts → | ||||
Partial evidence “Optima Communications International (OCI) is a Canadian contact center and business process outsourcer (BPO) specializing in regulated and complex industries, including utilities…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 18 | 303 contacts → | ||||
Indirect evidence “gevekom - Your better place to work.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 19 | 299 contacts → | ||||
Strong evidence “ACCUEIL is a leading Italian company in the field of Call Center and Business Process Outsourcing Services.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 20 | 289 contacts → | ||||
Indirect evidence “Current Vertical Focus: Real Estate - Lead Generation, Lead Conversion, Lead Qualification, Agent Recruiting Mortgage - Lead Conversion, Lead Qualification Insurance - Lead…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 21 | 284 contacts → | ||||
Strong evidence “Navigant Technologies is an ISO 9001-2008 certified international call center headquartered in Delhi, India.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 22 | 256 contacts → | ||||
Strong evidence “Boomsourcing (A Fusion CX Company) is a call center established in 2007.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 23 | 247 contacts → | ||||
Strong evidence “Rocket Connections is a sales and support platform specializing in contact center services.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 24 | 246 contacts → | ||||
Partial evidence “Since 1995, VOXDATA has been supplying outsourced call centre services, 24 hours a day, seven days a week, to meet all frontline customer relations needs.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 25 | 243 contacts → | ||||
Partial evidence “The Telemarketing Company is one of the UK's most trusted telemarketing agencies, delivering flexible, high-quality voice services, including pre and post sales research…” Source: RevenueBase Database · checked Sep 28, 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: inside sales call centers. 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 inside sales call centers.
- Partial evidence
- Its own public description names part of inside sales call centers, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name inside sales call centers. 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 2,298 inside sales call centers worldwide
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Inside sales call centers worldwide at a glance
As of Sep 28, 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 inside sales call centers, 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 inside sales call centers are linked below.
- What qualifies
- Companies worldwide whose own description of what they do matches “inside sales call centers”. 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 inside sales call centers), 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 inside sales call centers, 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, 3,298 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 28, 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.
Inside sales call centers by location
8 lists · largest firstEvery Inside sales call centers list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.
Countries
- Inside sales call centers based in the United States424
- Inside sales call centers based in India112
- Inside sales call centers based in the United Kingdom90
- Inside sales call centers based in Germany67
- Inside sales call centers based in Canada55
- Inside sales call centers based in France48
- Inside sales call centers based in the Netherlands45
- Inside sales call centers based in Spain35
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 inside sales call centers, 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 inside sales call centers are there worldwide?
RevenueBase identified 2,298 inside sales call centers 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?
Advanced Call Center Technologies, LLC, headquartered in Berwyn, tops this list with the largest team on record.
Which country has the most inside sales call centers?
The United States leads with 424 companies, followed by India (112) and the United Kingdom (90). Every inside sales call centers list by country and city is linked on this page.
Which city has the most inside sales call centers?
Rawalpindi leads with 47 headquartered companies, followed by Lahore (34) and Karachi (25).
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 3,298 verified decision-maker contacts tracked across these 2,298 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 28, 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.