Company lists · Data refreshed September 2026

Top 25 Sales development outsourcing firms worldwide

Name: Sales development outsourcing firms worldwide
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 29, 2026 15,641 companies tracked

RevenueBase identified 15,641 sales development outsourcing firms worldwide as of September 2026 and tracks 130,124 professional contacts across them, including 16,718 with verified work emails. The United States is the largest market and London the largest hub.

This list covers sales development outsourcing firms 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 29, 2026. Country and city lists for sales development outsourcing firms 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.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 29, 2026 86% judged on-target in blind review

15,641Companies

130,124Contacts tracked

16,718Verified emails

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The 25 largest sales development outsourcing firms worldwide

Ranked by team size

Top 25 of 15,641 sales development outsourcing firms worldwide, ranked by team size, largest first. Data refreshed Sep 29, 2026. RevenueBase Smart Search rates how each company's information relates to sales development outsourcing firms: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Marketsource INC	Partial evidence	Alpharetta, GA, United StatesHQ checked Sep 29, 2026	5,001-10,000	3,063 contacts →
	Partial evidence “MarketSource, an Allegis Group company, is a sales acceleration company focused on delivering better outcomes for many of the world’s most iconic brands.” Source: RevenueBase Database · checked Sep 29, 2026
2	Marketstar	Strong evidence	Ogden, UT, United StatesHQ checked Sep 29, 2026	1,001-5,000	2,446 contacts →
	Strong evidence “MarketStar is a global B2B sales outsourcing leader with 38+ years of experience driving predictable revenue growth.” Source: RevenueBase Database · checked Sep 29, 2026
3	Webhelp Enterprise	Partial evidence	Paris, FranceHQ checked Sep 29, 2026	10001+	1,795 contacts →
	Partial evidence “The Concentrix B2B sales practice is here to design, build and run projects for our clients.” Source: RevenueBase Database · checked Sep 29, 2026
4	Cience	Indirect evidence	Miami, FL, United StatesHQ checked Sep 29, 2026	201-500	1,068 contacts →
	Indirect evidence “CIENCE Technologies, Inc, founded in 2015 and headquartered in Denver, CO, is a pioneering global company in lead generation software and services, committed to transforming the…” Source: RevenueBase Database · checked Sep 29, 2026
5	Horatio	Partial evidence	New York, United StatesHQ checked Sep 29, 2026	1,001-5,000	860 contacts →
	Partial evidence “Horatio is a premier, tech-enabled outsourcing partner helping ambitious companies scale customer experience and complex business operations without compromising quality…” Source: RevenueBase Database · checked Sep 29, 2026
6	Memoryblue	Indirect evidence	Tysons, VA, United StatesHQ checked Sep 29, 2026	501-1,000	825 contacts →
	Indirect evidence “memoryBlue is the go-to partner for revenue leaders in B2B Tech looking to grow their pipeline engine.” Source: RevenueBase Database · checked Sep 29, 2026
7	ZAZ Vendas	Indirect evidence	Campinas, BrazilHQ checked Sep 29, 2026	501-1,000	796 contacts →
	Indirect evidence “Em um mercado cada vez mais competitivo, onde a eficiência em vendas massificadas e externas é um desafio constante, a ZAZ Vendas surge como a resposta definitiva.” Source: RevenueBase Database · checked Sep 29, 2026
8	Abstrakt Marketing Group	Indirect evidence	St Louis, MO, United StatesHQ checked Sep 29, 2026	501-1,000	724 contacts →
	Indirect evidence “We book the qualified meetings that fill your pipeline for any B2B company ready to grow.” Source: RevenueBase Database · checked Sep 29, 2026
9	Salebuild	Indirect evidence	Redwood City, CA, United StatesHQ checked Sep 29, 2026	n/a	708 contacts →
	Indirect evidence “Salesify, a leading provider of B2B demand generation services, helps our clients create pipeline and accelerate revenue by identifying, profiling, nurturing and connecting with…” Source: RevenueBase Database · checked Sep 29, 2026
10	Girnar Care	Indirect evidence	Jaipur, IndiaHQ checked Sep 29, 2026	501-1,000	649 contacts →
	Indirect evidence “We at Girnar Care work towards customer satisfaction and it is also a center of customer excellence.” Source: RevenueBase Database · checked Sep 29, 2026
11	DMF Sales&marketing	Partial evidence	Asnières Sur Seine, FranceHQ checked Sep 29, 2026	201-500	632 contacts →
	Partial evidence “MISSION DMF sales and marketing est un des tous premiers prestataires d’externalisation commerciale en France.” Source: RevenueBase Database · checked Sep 29, 2026
12	Infinity	Partial evidence	Cedar Rapids, IA, United StatesHQ checked Sep 29, 2026	501-1,000	609 contacts →
	Partial evidence “Infinity is an award-winning inside sales agency and consulting firm with 30 years of experience helping B2B companies maximize sales and drive revenue.” Source: RevenueBase Database · checked Sep 29, 2026
13	Telenet Marketing Solutions	Indirect evidence	Athens, GA, IndiaHQ checked Sep 29, 2026	201-500	553 contacts →
	Indirect evidence “From initial market awareness to the final stages of a complex B2B buying journey, modern buyers crave authentic interaction.” Source: RevenueBase Database · checked Sep 29, 2026
14	Movingdneedle Pvt. LTD	Partial evidence	Sterling Heights, MI, United StatesHQ checked Sep 29, 2026	51-200	528 contacts →
	Partial evidence “movingDneedle is a Business to Business Sales Lead Generation Company that provides fast and scalable, sales qualified leads through its unique Personalized Email Marketing…” Source: RevenueBase Database · checked Sep 29, 2026
15	The Pipeline Group	Indirect evidence	San Jose, CA, United StatesHQ checked Sep 29, 2026	201-500	523 contacts →
	Indirect evidence “The Pipeline Group helps B2B tech companies scale pipeline fast through our SDR-as-a-Service model.” Source: RevenueBase Database · checked Sep 29, 2026
16	Callbox INC	Indirect evidence	Encino, CA, United StatesHQ checked Sep 29, 2026	201-500	499 contacts →
	Indirect evidence “Callbox is the #1 trusted lead generation services and AI-Powered Growth Strategy Partner by enterprise and scaling businesses in the USA, Canada, Asia Pacific, Latin America…” Source: RevenueBase Database · checked Sep 29, 2026
17	Infoanalytica, INC	Partial evidence	San Jose, CA, United StatesHQ checked Sep 29, 2026	201-500	482 contacts →
	Partial evidence “InfoAnalytica is a B2B sales acceleration partner for mid-market and enterprise companies.” Source: RevenueBase Database · checked Sep 29, 2026
18	Smartsourcing	Partial evidence	Cebu, PhilippinesHQ checked Sep 29, 2026	201-500	474 contacts →
	Partial evidence “Smartsourcing is a global outsourcing company redefining how businesses scale through people-first solutions.” Source: RevenueBase Database · checked Sep 29, 2026
19	Saleshive	Indirect evidence	Denver, CO, United StatesHQ checked Sep 29, 2026	51-200	455 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 29, 2026
20	Alliance Pdms	Indirect evidence	Hurst, TX, United StatesHQ checked Sep 29, 2026	51-200	428 contacts →
	Indirect evidence “Alliance is a domestically operated, internationally recognized professional contact center specializing in lead generation and appointment setting.” Source: RevenueBase Database · checked Sep 29, 2026
21	The Lead Market	Indirect evidence	Nagpur, IndiaHQ checked Sep 29, 2026	51-200	387 contacts →
	Indirect evidence “TLM empowers businesses to generate revenue through their qualified leads.” Source: RevenueBase Database · checked Sep 29, 2026
22	Beyond Codes INC	Partial evidence	Simi Valley, CA, United StatesHQ checked Sep 29, 2026	201-500	380 contacts →
	Partial evidence “Beyond Codes is a global B2B lead generation and appointment-setting agency trusted by some of the world's leading technology companies to build enterprise sales pipeline.” Source: RevenueBase Database · checked Sep 29, 2026
23	EBQ	Partial evidence	Austin, TX, United StatesHQ checked Sep 29, 2026	201-500	377 contacts →
	Partial evidence “EBQ is an outsourced sales and marketing organization that provides services to help companies scale.” Source: RevenueBase Database · checked Sep 29, 2026
24	Cobmax	Partial evidence	Sao Jose Do Rio Preto, BrazilHQ checked Sep 29, 2026	501-1,000	376 contacts →
	Partial 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 29, 2026
25	Winche Redes Comerciales	Indirect evidence	Barcelona, SpainHQ checked Sep 29, 2026	501-1,000	359 contacts →
	Indirect evidence “Winche Redes Comerciales es la compañía experta en externalización de la fuerza de Ventas y en la gestión del punto de venta.” Source: RevenueBase Database · checked Sep 29, 2026

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: sales development outsourcing firms. 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 sales development outsourcing firms.
Partial evidence: Its own public description names part of sales development outsourcing firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name sales development outsourcing firms. 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 15,641 sales development outsourcing firms worldwide

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Sales development outsourcing firms worldwide at a glance

As of Sep 29, 2026

12.8%Verified-email coverage

8.3Average contacts per company

1-10Median size (employees)

2.7%Largest-city concentration · London

Sep 29, 2026Page data refreshed

Companies by employee count

1-10

10,458

11-50

3,810

51-200

1,021

201-500

238

501-1,000

1,001-5,000

5,001-10,000

10001+

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 sales development outsourcing firms, 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 sales development outsourcing firms are linked below.
What qualifies: Companies worldwide whose own description of what they do matches “sales development outsourcing firms”. 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 sales development outsourcing firms), 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 sales development outsourcing firms, 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, 16,718 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 29, 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.

Sales development outsourcing firms by location

77 lists · largest first

Every Sales development outsourcing firms list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.

Countries

Cities

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 sales development outsourcing firms, 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 sales development outsourcing firms are there worldwide?

RevenueBase identified 15,641 sales development outsourcing firms 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?

Marketsource INC, headquartered in Alpharetta, tops this list with the largest team on record.

Which country has the most sales development outsourcing firms?

The United States leads with 3,575 companies, followed by the United Kingdom (1,208) and India (1,083). Every sales development outsourcing firms list by country and city is linked on this page.

Which city has the most sales development outsourcing firms?

London leads with 423 headquartered companies, followed by Pune (219) and New York (182).

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 16,718 verified decision-maker contacts tracked across these 15,641 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 29, 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.