The best cold email agencies for B2B lead generation combine strong deliverability infrastructure, precise targeting, and proven results across client campaigns. After reviewing industry data and client outcomes, agencies like Infinite, Belkins, Outbound System, and SalesHive consistently rank among the top performers.
At Infinite, we’ve launched 280+ email campaigns for B2B technology companies, achieving a 92% inbox deliverability rate and 47% conversation rate across our client base. Through this work, we’ve learned what separates effective cold email partners from the rest.
This guide examines 10 agencies based on their deliverability infrastructure, targeting accuracy, client results, and pricing models.
What Makes a Cold Email Agency Effective
Before comparing specific agencies, it helps to understand what actually drives results in cold email outreach.
Deliverability infrastructure determines whether your emails reach inboxes or spam folders. The industry average for inbox placement hovers around 48%, according to Belkins. Top agencies invest in dedicated sending servers, proper authentication (SPF, DKIM, DMARC), and gradual warm-up processes to achieve 90%+ deliverability.
Targeting accuracy affects response rates more than most businesses realize. Sending 10,000 emails to poorly matched prospects produces worse results than 1,000 emails to decision-makers who actually need your solution. The best agencies spend significant time on prospect research and list building before sending a single message.
Multi-channel integration has become standard among top performers. Cold email works better when combined with LinkedIn outreach. 89% of B2B marketers use LinkedIn for lead generation, and the platform’s professional data makes targeting more precise. “LinkedIn profiles contain verified business titles and company affiliations that Facebook and Instagram don’t capture,” notes Tom Nadav, founder of Infinite. “That structural difference drives our targeting accuracy to 97%.”
10 Best Cold Email Agencies for B2B Lead Generation
1. Infinite
Infinite specializes in combined LinkedIn and cold email outreach for technology companies, startups, and professional service firms. Founded in 2021, the agency has built a reputation for precision targeting and strong conversion rates.
Key metrics:
- 47% conversion rate from outreach to active conversations
- 92% inbox deliverability rate
- 10:1 average ROI across 200+ tech client campaigns
- 25,000+ meetings scheduled since founding
Infinite’s approach dedicates roughly 50% of campaign time to prospect research and segmentation. This research-heavy process helps explain the high conversation rates. The agency works from a database of 300+ million verified emails with a 95% verification rate.
Services include:
- Cold email outreach with dedicated domain setup
- LinkedIn lead generation campaigns
- Fundraising outreach for startups
- Complete authentication setup (SPF, DKIM, DMARC)
- AI-powered response classification
Case study: A 12-month campaign for CyVers, a Web3 cybersecurity firm, generated 692 qualified leads at $23 cost-per-lead. The campaign reached 13,700+ blockchain industry executives with a 7.04% lead rate.
Pricing: Email outreach starts at $1,497/month. LinkedIn outreach starts at $1,897/month. Three-month minimum commitment.
2. Belkins
Belkins is a globally recognized agency combining cold email with LinkedIn outreach and cold calling. With 8+ years in the industry and 200+ specialists, they’ve generated $2 billion+ in revenue for 1,000+ clients.
Key metrics:
- 4.9/5 rating on Clutch, 4.8/5 on G2
- Inc. Top Lead Generation Service Provider (2024)
- Multi-channel cadence across email, LinkedIn, and phone
Belkins emphasizes strategic campaign design and manual data validation. Their omnichannel approach reinforces messaging across multiple touchpoints.
Case study: A campaign for a mini-computer manufacturer delivered 109 qualified appointments with an 80% open rate.
Pricing: Full-service engagements start around $5,500/month.
3. Outbound System
Outbound System focuses exclusively on cold email with a strong emphasis on deliverability infrastructure. They build private email servers for each client rather than using shared infrastructure.
Key metrics:
- 98%+ inbox deliverability (vs ~48% industry average)
- $26 million+ in closed revenue for clients
- 127,000+ leads delivered
- 600+ clients served
Their pay-per-lead model with month-to-month contracts makes them a lower-risk option for companies testing cold email.
Services include:
- Dedicated sending servers per client
- Multi-source data targeting
- Advanced copywriting frameworks
- Month-to-month flexibility
Pricing: Pay-per-lead model with no long-term commitments.
4. SalesHive
SalesHive combines AI technology with human SDR teams. Their “eMod” AI engine auto-personalizes emails with context like prospect job changes or company news, while US-based SDRs handle complex follow-ups.
Key metrics:
- 117,000+ B2B meetings booked
- $2.1 billion in sales pipeline generated
- 1,500+ companies served
Services include:
- AI-powered email personalization
- US-based SDR teams
- Multi-channel outreach (email, phone, LinkedIn)
- 30-page sales playbook for each client
Pricing: Tiered packages based on meeting targets. Starter (~$4K-$5K/month) targets 20-30 meetings/quarter. Growth ($8K) targets 40-55 meetings/quarter. Crush ($12K) targets 60-90 meetings/quarter.
5. Cleverly
Originally known for LinkedIn lead generation, Cleverly now offers done-for-you cold email campaigns. They leverage data from thousands of B2B campaigns to craft personalized outreach.
Key metrics:
- Data-driven personalization from thousands of campaigns
- Multi-step sequences with A/B testing
- Personalized “icebreaker” introductions for each prospect
Services include:
- ICP-based list building
- Custom email copy with personalization
- Ongoing A/B testing and optimization
- LinkedIn profile optimization
Pricing: Monthly retainer with custom quotes.
6. Pearl Lemon Leads
Pearl Lemon Leads is a UK-based agency running fully managed cold email campaigns alongside social media, cold calling, and SEO. They emphasize GDPR and CAN-SPAM compliance.
Key metrics:
- Strict GDPR and CAN-SPAM compliance
- Multi-channel approach (email, LinkedIn, calls, content)
- Strong presence with UK/EU tech firms
Services include:
- Personalized email content focused on value
- Compliance-first deliverability practices
- Outsourced SDR team model
Pricing: Cold email packages from approximately £2,497/month (~$3.3K USD). Multi-channel programs from £3,497/month (~$4.6K USD).
7. CIENCE
CIENCE takes a human-driven approach, assigning dedicated SDR teams and researchers to each client rather than relying heavily on automation.
Key metrics:
- High-touch, research-intensive process
- Top-ranked on Clutch
- Serves mid-market and enterprise B2B companies
Services include:
- Dedicated SDR and research teams
- Manual prospect list building and verification
- Customized email and LinkedIn sequences
- Quality-focused approach over volume
Pricing: Custom pricing based on scope and team size.
8. SalesBread
SalesBread deliberately keeps outreach volumes low to focus on ultra-personalized messaging. They only target prospects who are active on LinkedIn, pre-qualifying engagement potential.
Key metrics:
- Low-volume, high-personalization approach
- “CCQ” framework: Commonalities, Compliments, Questions
- LinkedIn activity verification before email outreach
Services include:
- LinkedIn + email multi-touch campaigns
- Personalized messaging based on prospect research
- Small, highly targeted list focus
Pricing: Starting around $3,000/month plus setup fee.
9. Superhuman Prospecting
Superhuman Prospecting emphasizes cold calling supported by email and LinkedIn, with 100% US-based SDRs.
Key metrics:
- 100% US-based SDR team
- Industry experience in SaaS, manufacturing, insurance
- Multi-channel coordination
Services include:
- Phone-focused outreach with email/LinkedIn support
- Personalized messaging based on value proposition
- B2B list building
- Coordinated multi-channel campaigns
Pricing: Custom quotes based on SDR allocation.
10. memoryBlue
memoryBlue is a veteran sales development firm (20+ years) operating as an outsourced SDR provider, particularly for technology and public sector companies.
Key metrics:
- 600+ employees
- Serves technology and public sector
- Multilingual outreach capabilities
- Notable clients include MobileIron, Box, Cloudera
Services include:
- Full-funnel sales development
- Multi-channel outreach (calls, email, LinkedIn, events)
- Sales Training Academy for SDR development
- International campaign capabilities
Pricing: Tailored based on SDR count and campaign complexity.
Cold Email Agency Comparison Table
| Agency | Primary Approach | Starting Price | Best For |
| Infinite | LinkedIn + Email, tech focus | $1,497/month | Tech companies, startups |
| Belkins | Omnichannel (email, LinkedIn, calls) | $5,500/month | Enterprise, global B2B |
| Outbound System | Email-only, infrastructure focus | Pay-per-lead | Risk-averse buyers |
| SalesHive | AI + human SDRs | $4K-$5K/month | Scalable outbound |
| Cleverly | Data-driven LinkedIn + email | Custom quote | SMB/mid-market |
| Pearl Lemon Leads | Multi-channel, compliance-focused | ~$3.3K/month | UK/EU companies |
| CIENCE | Human-centric SDR teams | Custom quote | Enterprise, complex sales |
| SalesBread | Low-volume, high-personalization | $3,000/month | High-value B2B |
| Superhuman Prospecting | Phone + email/LinkedIn | Custom quote | US-focused outreach |
| memoryBlue | Outsourced SDR provider | Custom quote | Tech, public sector |
How to Choose a Cold Email Agency
Evaluate deliverability infrastructure. Ask how the agency handles domain setup, authentication, and warm-up processes. Agencies achieving 90%+ inbox placement rates invest in dedicated infrastructure rather than shared sending systems.
Review targeting methodology. Understand how the agency builds prospect lists. Multi-source data verification and role-specific targeting produce better results than basic list scraping.
Request relevant case studies. Look for results from companies similar to yours in size, industry, or target market. Metrics like reply rates, meetings booked, and cost-per-lead matter more than vanity metrics.
Understand the pricing model. Monthly retainers offer predictability. Pay-per-lead models align cost with results but typically carry higher per-lead rates. Consider contract length requirements as well.
Assess communication and reporting. The agency should provide transparent dashboards showing campaign performance. Regular optimization based on data helps improve results over time.
Get Started with B2B Lead Generation
The right cold email agency becomes an extension of your sales team, filling your pipeline with qualified prospects while you focus on closing deals. Each agency on this list has proven results, but the best fit depends on your specific industry, budget, and growth goals.If you’re a technology company looking for combined LinkedIn and email outreach, schedule a strategy call to discuss how our approach might work for your business.
