10 Best Cold Email Agencies in 2026, Compared
Ten cold email agencies for 2026, from Belkins and CIENCE to Growth Engine X and Cleverly, with the channels each runs, how each bills in its own words, and what to ask before you sign.
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The best cold email agencies in 2026 are Belkins for appointment setting with a meeting guarantee, CIENCE and SalesHive for email run alongside SDR calling, Growth Engine X for high-volume email into large markets, Cleverly for done-for-you email on a flat retainer, LevelUp Leads and Whistle for outsourced SDR teams that include email, Martal and Leadium for omnichannel programs, and Anfloy when cold email should be one channel of a whole GTM motion you own.
Anfloy publishes this list and is on it. Every fact about the other nine comes from the agency's own site, read on November 9, 2026. Each ranks on Google for the query or gets named by ChatGPT, Gemini, Perplexity or Claude.
We run cold email ourselves, and who is on the list decides the result more than the copy or the volume. For The Voice Box we bought no list. A scraper picked people off buying signals, then each was scored against the ICP, sorted into one of three tiers and given a verified email, with sends from The Voice Box's own infrastructure. The first campaign got an 11.4% reply rate, where cold email usually sits at 1 to 2%, and booked 10 meetings. Read the case study or book a call.
The 10 cold email agencies at a glance
| Agency | Channels | Best for | How they bill | What to check |
|---|---|---|---|---|
| Belkins | Email, plus LinkedIn and warm calls | Teams that want a meeting floor in the contract | Custom proposal; starter price published; pay-per-meeting program | Which channels are add-ons |
| CIENCE | Email, phone, social via SDRs | Teams that want published prices | Monthly team and platform fees, per-SDR fee, bonus, setup fee | The bonus math at full target |
| SalesHive | Email plus phone | Teams that want calling and email from one SDR | One custom-quoted monthly fee | No email-only managed plan |
| Growth Engine X | Large markets and high volume | Free test campaign for those who qualify | Your market size | |
| Cleverly | Done-for-you email on a fixed budget | Flat monthly retainer or pay per lead | What counts as a lead | |
| LevelUp Leads | Phone-led, email, LinkedIn | An outsourced SDR team | Published packages in three tiers | How much of the plan is calling |
| Whistle | Phone, email, LinkedIn | A managed SDR department | Quoted on the intro call | Email-only scope versus full SDR |
| Martal | Email, LinkedIn, phone | Omnichannel programs on intent data | Pricing on request | Get the price in writing |
| Leadium | Email, phone, LinkedIn, SMS, gifting | A US-based team | Month-to-month, scoped on a consult | No guarantee on meetings |
| Anfloy | Email, LinkedIn, phone, content | Small teams handing over the whole GTM motion | Retainer, or base plus revenue share | You want the motion run, not only email |
The agencies, one by one
Belkins
Belkins sells cold email as appointment setting and publishes its averages: a 6%+ email reply rate. It says the average starter price is from $5,000 and lists 100+ guaranteed appointments a year,, plus a pay-per-meeting program. Setup covers DNS, new mailboxes and warmup in small batches before scaling, and it says each reply is processed by hand. LinkedIn and warm calls are add-ons.
CIENCE
CIENCE is the most open about price. Its pricing page lists a campaign team at $2,000 per month and offshore SDRs starting at $1,750 per SDR per month, plus a performance bonus and a one-time setup fee. It runs month to month with no contracts, a person reads every reply, and setup is live in less than 14 days by its own count.
SalesHive
SalesHive pairs email with phone by design. Its published managed plans have no email-only option, and it charges one custom-quoted monthly fee with no setup fees and no per-meeting pricing. One case study counts 183 meetings booked by email for a commercial insurance client. Sending setup covers SPF, DKIM, DMARC and MX.
Growth Engine X
Growth Engine X is the pure email specialist here. It reports 8M+ emails a month and 62K+ positive responses in 2025. Companies that qualify get a test campaign at no cost. It says small markets under 40K contacts are usually not a fit, and that all work, including domains, inboxes and lists, is transferable to you.
Cleverly
Cleverly sells done-for-you cold email and says it books 10 to 30 qualified B2B meetings a month. It bills a flat monthly retainer or pay per lead, month to month with no contracts. One case study describes an Azure setup with 2 USA IPs and 100 Outlook accounts.
LevelUp Leads
LevelUp's email service covers list building, domain warmup and DKIM, DMARC and SPF setup, with 1000+ new contacts sourced a month. The wider offer is an outsourced SDR team led by cold calling, sold in three tiers starting at $5,000, with 10 to 14 day onboarding at no charge.
Whistle
Whistle's cold email service covers targeting, writing, sending and replies. It targets on role, size, industry and signals like funding, hiring or tech stack, and it sets up domains and warms inboxes before launch. It says over 350 companies trust it, and it prices by scope with a quote on the intro call. The core product is an SDR team on phone, email and LinkedIn.
Martal
On November 9, 2026, ChatGPT, Gemini, Perplexity and Claude all named Martal. It says over 2,000 B2B brands trust it, builds lists on 3,000 buying intent signals, and adds LinkedIn and phone to email. It sends from subdomains or new domains to protect your primary one. Cold email pricing is on request.
Leadium
Leadium runs appointment setting across email, phone, LinkedIn, SMS and gifting with a 100% US based team. All contracts are month-to-month, and it says it does not guarantee meeting outcomes.
Anfloy
Cold email is one channel for us. For small teams we become the go-to-market team and own the result: pipeline and booked, qualified meetings. That covers strategy, offers, funnels, outbound across email, LinkedIn and the phone, founder-led content and agentic RevOps with a person approving what goes out. The data, mailboxes and accounts are set up in the client's name, and they own it. The Voice Box went from nothing to a live motion in five days, and Apify's case study on our engine reports reply rates as high as 11% and $234,000 in qualified pipeline across three campaigns. For pure volume into a very large market, Growth Engine X fits better.
What to check before you hire a cold email agency
Ask these on the first call.
- Whose domains and mailboxes. Separate sending domains protect your main one, as Martal and SalesHive describe. Ask whose name they are registered in. If it is the agency's, the reputation you paid for leaves with them.
- Who owns the list and the replies. The contacts and the reply history are the asset. Put a full export in the contract.
- Warmup. Instantly's guidance, per our stack notes, is 2 weeks minimum per mailbox, 3 to 4 recommended. Sends promised in week one mean warmup got skipped.
- Deliverability. SPF, DKIM and DMARC are the minimum. Ask who checks domain health and what happens the week a domain lands in spam. A good answer names a person.
- The list. In our own system an email waterfall took coverage from 40% to 80%. On catch-all-heavy lists one verifier passed 1 address in 8, so we switched. Ask which verifier they use.
- What a meeting means. An accepted invite, a held call and a call with someone in your ICP are three different numbers. Agree which one the report counts.
- Replies and copy. Our rule: nothing reaching a stranger is written by a model at send time. Ask to see live sequences.
The usual failure is volume over relevance. A weak campaign gets more mailboxes and more sends to the same loose list, the report looks busy, and the domains burn. What works is a tighter list and a real reason to write to each person now.
Cold email agency vs running signal-based outbound in-house
An agency rents you a team and a sending setup. It fits when you need meetings this quarter. The targeting logic, the lists and often the domains stay with the agency.
In-house, the system watches for buying signals, qualifies and verifies people, and sends from infrastructure in your name. Someone has to own it. For small teams that can be us, measured on qualified meetings and reviewed weekly. More in our cold email playbook, the sending infrastructure lesson and GTM.
My take: hire an agency if outbound is a side channel. If it is how you grow, keep the engine, the data and the leads on your side.
Frequently asked questions
How much does a cold email agency cost?
Among agencies that print prices, Belkins and LevelUp Leads both start from $5,000, and CIENCE lists a $2,000 monthly campaign team plus SDRs from $1,750 each per month. SalesHive, Whistle and Martal quote per scope. Our billing is on [how we work](/how-we-work).
Do cold email agencies guarantee meetings?
Some do. Belkins lists 100+ guaranteed appointments a year. Leadium says it does not guarantee outcomes.
Who owns the domains, mailboxes and lists if I leave?
Ask before signing. Growth Engine X says all work is transferable. In our builds the infrastructure is set up in the client's name from day one.
How long until the first campaign sends?
Usually two to four weeks. Mailbox warmup alone takes 2 weeks minimum. Growth Engine X schedules onboarding and warm-up first, and CIENCE says setup is live in less than 14 days.
Is a cold email agency the same as an outsourced SDR?
They overlap. LevelUp, Whistle and SalesHive sell SDR teams that include email. Growth Engine X and Cleverly sell email alone.
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