Ten agencies working the GTM engineering and outbound space for B2B SaaS, compared on what they build, who they serve, and what they charge. Alphabetical, not ranked.
TL;DR
"GTM engineering agency" gets used loosely. Some of the ten agencies below build outbound infrastructure the way the term implies: enrichment waterfalls, signal detection, CRM-integrated qualification, running on a client's own stack. Others are closer to a traditional SDR-as-a-service model with a Clay table somewhere in the pipeline. Both are legitimate models for different problems. This page compares them on what they actually build, who they say they serve, and what they charge where that's public, so the comparison is useful before you're on a call with any of them.
A GTM engineering agency builds a system: enrichment, signal detection, AI-assisted personalization, deliverability infrastructure, and CRM attribution, engineered to run largely on its own. An SDR-as-a-service agency staffs the outbound motion: reps who work a list, follow a sequence, and book meetings, with the infrastructure underneath handled less visibly or less at all. Neither is strictly better. A company with no outbound motion and no internal capacity to run one often wants reps. A company that already has reps but a broken or absent data layer usually wants the system. Several agencies below explicitly combine both.
| Agency | What they build | Who they serve | Pricing model |
|---|---|---|---|
| Astra GTM | Signal-based outbound, data infrastructure, and agentic Claude workflows, engineered inside the client's own stack | B2B SaaS and mid-market revenue teams; embedded engagement, three-month minimum | Scoped per engagement, not published |
| Belkins | Omnichannel SDR-as-a-service: cold email, cold calling, LinkedIn, ABM | B2B across 50+ industries; broad-market, not vertical-specific | Not published (quote-based) |
| CIENCE | Managed SDR execution plus a "Revenue System Setup" build phase covering targeting, campaign management, and data ops; now trades under the name "GTM services by graph8" | B2B and enterprise; cites Okta, Microsoft, Uber, and Salesforce as clients | Publishes several starting prices: GTM setup from $5,000 one-time, a $2,000/mo strategic-team plan, a $499/mo self-serve platform plan, or $7,499 for an all-in first month. Also publishes a 60-day "Standard" build package from $9,500 |
| ColdIQ | Leads with a self-serve GTM data API product ("build your revenue engine inside Claude Code"; 40+ providers, 700+ endpoints) alongside a managed agency service | B2B SaaS, fintech, and professional services | API product has published self-serve tiers: free, $99/mo, $199/mo, $499/mo, and custom Enterprise. Managed-service (agency) pricing not published |
| DarwinApps GTM | Funnel diagnostic followed by an infrastructure build across HubSpot, Salesforce, or Clay | B2B SaaS, roughly $10M-$100M ARR | Three published tiers (audit, build sprint, optimization retainer), no dollar figures listed |
| DevCommX | Signal-based prospecting and AI multichannel outreach with CRM-integrated qualification | B2B startup founders and RevOps leaders | Publishes a starting price of $4,500/mo (per their own service pages), 3-month initial term |
| Frontal | Unified data and buying-signal layer feeding signal-triggered outreach across email, LinkedIn ads, and LinkedIn content | B2B companies with product-market fit, selling into named accounts (no ARR range published) | Fixed price for a 90-day build (amount not published), then month-to-month for ongoing execution |
| OneGTM | Signal-driven RevOps and outbound systems; positions explicitly against generic outbound | Early- and growth-stage companies with lean GTM teams | Not published |
| The Kiln | Custom outbound automation, lead qualification, inbound enrichment, and CRM data cleaning built on Clay. Acquired by 2X in January 2026 (announced on their own homepage) and now operates as part of 2X's offering rather than as a fully independent shop | Not published on their site | Not published |
| Understory Agency | "Allbound": paid media, GTM engineering, LinkedIn content, and RevOps run as one coordinated system | B2B SaaS and AI-native companies past product-market fit; roughly six months for most engagements, four for smaller or earlier-stage companies | Flat, tiered retainer scoped to a client's ad spend (not a fee amount) for paid media; GTM engineering pricing custom, not published |
Astra runs as an embedded team inside a client's existing stack rather than as a parallel campaign vendor: three-month minimum, most engagements past twelve. Recent engagements: 23 ICP-fit meetings a month on average from zero outbound at Clipper Defense (5+ deals closed, 2 new service lines launched), a Clay-based acquisition-scoring pipeline at DealRoom that expanded TAM 50%+ without a PitchBook subscription, $1.5M in qualified pipeline in 4 months at Pricing I/O, and 35+ new clients plus $150K+ in revenue through cold email at Amadeus Vanilla. Full detail on each is in the case studies section.
A note on how this list was built
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