Cold email still opens more B2B sales conversations than most channels, but running it well is a full-time job. Lists need researching, sending domains need warming up, copy needs testing, and replies need answering the same day.
That is why many B2B companies hand cold email to a specialist agency. The agencies below differ in team size, channels and contract terms, so the right pick depends on the buyer and the budget.
Each profile is based on the agency’s own published information.
1. OutreachBloom
OutreachBloom is a B2B agency based in Olympia, Washington that runs cold email end to end. It builds prospect lists, sets up dedicated sending infrastructure, writes personalized copy and handles every reply until a meeting is booked.
The agency works with B2B SaaS and services companies of roughly 10 to 200 people. Alongside cold email, it runs LinkedIn outreach and organic Reddit marketing for clients who want more than one channel.
Best for: B2B SaaS and services teams that want cold email fully handled, from research to booked meetings.
Worth knowing: Its focus is B2B buyers, so consumer brands and local businesses are not its core fit.
2. Belkins
Belkins is a B2B lead generation and appointment-setting agency founded in 2017. It is headquartered in Dover, Delaware, with offices in Colorado, Illinois and London.
Cold email sits at the center of its programs, run by a dedicated account manager and SDR with manual lead research and ongoing deliverability work. LinkedIn outreach and calling are available as add-ons.
Best for: Companies that want campaigns measured in booked meetings.
Worth knowing: LinkedIn and calling cost extra rather than coming in every package.
3. Martal Group
Martal Group has run outbound sales programs for 15 years and employs more than 200 onshore sales executives. It is based in Oakville, Ontario, with offices in San Francisco, New York and France.
One team coordinates cold email, cold calling and LinkedIn outreach for each client. Campaigns send from separate, warmed-up domains to protect the client’s main domain.
Best for: Teams that want email, phone and LinkedIn run together.
Worth knowing: Pricing and contract terms are not published, so both need checking on the first call.
4. SalesHive
SalesHive is a remote-first sales development agency founded in 2016, with a US-based core SDR team. Its SDRs work on a platform the company built in-house.
The agency reports more than 106,000 qualified meetings booked and more than 1,500 client accounts launched.
Best for: US companies that want cold calling and cold email from one team.
Worth knowing: Phone is a large part of its model, so email-only buyers may pay for more than they need.
5. Leadium
Leadium is a fully managed outbound agency with more than ten years in business and a 100% US-based team. It is headquartered in Las Vegas, Nevada.
Each client gets a custom prospecting plan and dedicated SDRs covering email, phone and LinkedIn. All contracts run month to month.
Best for: Buyers who want to test outsourced outbound without a long commitment.
Worth knowing: A US-only team is best suited to US markets.
6. CIENCE
CIENCE is a Miami-based appointment-setting and lead generation firm founded in 2016. graph8 has acquired its assets.
A single SDR per account handles email, phone and LinkedIn outreach. The company reports more than 2,500 B2B clients and publishes more than 115 case studies.
Best for: Companies that want one SDR covering every channel.
Worth knowing: The change of ownership is worth asking about before a long engagement.
7. Sopro
Sopro is a UK multi-channel prospecting service founded in 2015 by Rob Harlow and Ryan Welmans.
It pairs email outreach with LinkedIn, display ads and gifting, and gives clients a dedicated account manager and a reporting portal.
Best for: Teams that want email backed by ads and LinkedIn.
Worth knowing: The wider channel mix may be more than a small team needs for a first campaign.
Choosing a Cold Email Agency
Start with deliverability. Agencies that send from separate, warmed-up domains protect the main company domain. Then check who handles replies, which channels are included and how long the contract runs.
For B2B SaaS and services companies that want cold email run end to end, OutreachBloom tops this list. Teams that need large SDR headcount or phone-heavy programs may find a better fit further down.