List building agencies
25 agencies in the index offer list building. Ranked by the evidence on record, the first three are CIENCE (Denver, US, from $2,499 a month), Hypergen (HQ not published, from $5,000 a month) and Leadium (Las Vegas, US, from $3,500 a month). List building agencies research and verify prospect lists that match an ideal customer profile, with contact data. Contact data decays every month, so ask how emails and phone numbers are verified and how often the list is refreshed. 10 of the 25 publish a monthly minimum, from $2,499 to $10,000, with a median of $5,000. 0 offer pay-per-meeting pricing and 1 offers pay-per-lead; the rest work on a retainer or do not say. Besides list building, the services most often offered here are cold email, appointment setting and LinkedIn outreach. 9 build on Clay, 4 work inside HubSpot and 14 use their own or undisclosed tools. 14 have a Clutch or G2 rating on file with the date it was read. Before signing, ask for a sample sequence, the definition of a qualified meeting and who owns the domains and data afterward.
| # | Agency | HQ | Stack | From (monthly) | Model | Proof | Badges |
|---|---|---|---|---|---|---|---|
| 1 | CIENCE↗ Offices in Denver, Kyiv, Guadalajara; $5k setup + $2,499+/mo management reported | Denver, US | HubSpot, Custom | $2,499 | Retainer | G23.7 (180) | SDR PodEditor's Pick |
| 2 | Hypergen↗ Lite plans from $6.5k/mo with 6-month minimum also reported | Not published | Clay, HubSpot | $5,000 | Retainer | Clutch5.0 (15) | Clay NativeVerified DeliverabilityEditor's PickTop Outbound Agency US 2026 |
| 3 | Leadium↗ Cold calling from $3.5k/mo, multichannel $4-5k; caps roster at ~30-35 clients | Las Vegas, US | Custom | $3,500 | Retainer | Clutch5.0 (88) | SDR Pod |
| 4 | EBQ↗ Flat monthly fee ~$5-10k; bundles marketing support | Houston, US | Custom | $5,000 | Retainer | Clutch4.8 (44) | SDR Pod |
| 5 | SalesAR↗ | UK | Custom | Ask | Not published | Clutch4.8 (136) | Top Outbound Agency UK 2026 |
| 6 | Callbox↗ Delivery largely Philippines-based; campaign pod model; Colombia unit for LatAm | Encino, US | Custom | Ask | Not published | Clutch4.6 (128) | SDR PodEditor's PickTop Outbound Agency APAC 2026 |
| 7 | Superhuman Prospecting↗ Cold-calling-first, email and LinkedIn as support | Not published | Custom | Ask | Not published | Clutch5.0 (46) | none |
| 8 | Blue Modern Advisory↗ Clay-to-Snowflake reporting; regulated-industry focus | New York, US | Clay | $10,000 | Retainer | n/a | Clay Native |
| 9 | DealDeploy↗ PE deal-sourcing niche; deliverables in client-owned GitHub | New York, US | Clay, Custom | $10,000 | Retainer | n/a | Clay Native |
| 10 | Rillation Revenue↗ Visitor ID + lookalike outbound; 30+ tools stack | New York, US | Clay, Smartlead | $5,000 | Retainer | n/a | Clay Native |
| 11 | The Kiln↗ Clay-native; reported acquired by 2X | Brooklyn, US | Clay | $10,000 | Retainer | n/a | Clay Native |
| 12 | Operatus↗ Salesforce/HubSpot consulting plus Clay enrichment | New York, US | Clay, HubSpot | Ask | Not published | G24.7 (29) | Clay Native |
| 13 | SalesHive↗ US-based SDRs; Starter $5k/mo, Growth $8k, Crush $12k; month-to-month | US | Custom | $5,000 | Retainer | G21.3 (4) | Verified DeliverabilitySDR PodEditor's Pick |
| 14 | Leadbird↗ Pay-per-lead, no retainer | Not published | Custom | Per lead | Pay-per-lead | G24.6 (27) | Verified Deliverability |
| 15 | Spring Drive↗ London + New York | London, UK | Clay | Ask | Not published | Clutch4.9 (12) | Clay Native |
| 16 | IntentSignal↗ Retainer or hybrid retainer+performance; small client roster | US | Instantly, HubSpot, Custom | Ask | Retainer | Clutch5.0 (3) | Verified Deliverability |
| 17 | Sopro↗ Also runs a Miami entity | Brighton, UK | Custom | Ask | Not published | G24.9 (17) | Top Outbound Agency UK 2026 |
| 18 | SalesBread↗ Manual LinkedIn outreach; ~$3k/mo + setup, month-to-month | US | Custom | $3,000 | Retainer | n/a | none |
| 19 | OutreachBloom↗ Email-only done-for-you; no long-term contracts; now also sells Reddit/AI SEO | Seattle, US | Custom | Ask | Not published | Clutch5.0 (2) | Verified Deliverability |
| 20 | Growth Engine X↗ High-volume cold email; free test campaign; 3-month minimum | New York, US | Clay, Smartlead, Instantly | Ask | Retainer | n/a | Clay NativeVerified Deliverability |
| 21 | Zevenue↗ Clay TAM builds plus rep training | Toronto, CA | Clay | Ask | Not published | n/a | Clay NativeTop Outbound Agency Canada 2026 |
| 22 | Beanstalk Consulting↗ Productized flat-fee outbound | US | Custom | Ask | Not published | n/a | none |
| 23 | Focus One↗ | IE | Custom | Ask | Not published | n/a | none |
| 24 | UltraGrowthMedia↗ Performance-aligned meeting targets; no long-term contracts | Not published | Custom | Ask | Not published | n/a | none |
| 25 | Pearl Lemon Leads↗ US arm at pearllemonleadsusa.com | London, UK | Custom | Ask | Not published | n/a | SDR Pod |
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Related pages
Same service, by region
Parent: All agencies
Questions
- How much does a list building agency cost?
- 10 of the 25 publish a monthly minimum, from $2,499 to $10,000, with a median of $5,000. Setup fees and minimum terms vary, so ask for both before comparing monthly prices.
- Retainer or pay-per-meeting?
- A retainer buys an agreed scope each month and suits a defined ICP with at least three months of runway. Pay-per-meeting moves the risk to the agency and suits offers with a short sales cycle. On this page, 0 agencies offer pay-per-meeting pricing and 1 pay-per-lead.
- How long until results?
- New sending domains need two to three weeks of warm-up before volume goes out, and list building runs alongside it. Most agencies quote first meetings in weeks four to eight.
- Does the stack matter?
- 9 of the 25 build on Clay and 4 work inside HubSpot. Ask who owns the sending domains, the data and the workflows when the engagement ends; some agencies hand them over and some keep them.