If you’ve been burned by an agency before — or you’re watching your pipeline stall despite a full tech stack — you already know that picking the wrong GTM partner is expensive. Not just in fees, but in the months of runway it costs you.
The market has also gotten harder to read. A category that barely existed three years ago now includes AI SDR software, single-channel outbound shops, integrated GTM agencies, and a newer breed sometimes called GTM engineering firms. These are not interchangeable, and choosing the wrong type of vendor is its own mistake, before you even get to picking a specific one.
This guide gives revenue leaders — VPs of Sales, Heads of Growth, and founders at post-PMF B2B companies — a structured way to evaluate any agency operating in this space, followed by a comparison of the leading options and a clear explanation of what separates them.
First: Understand the Four Types of Vendors
Before asking a single question, you need to know what kind of vendor you’re talking to. These categories answer different problems.
AI SDR Software (e.g., Artisan, 11x) — These are platforms, not services. You buy a seat, configure the tool, and the software handles prospecting and outreach automatically. They are fast to deploy and low in overhead, but they sit on top of whatever data and signals you already have. If your underlying data is messy or your ICP definition is weak, the AI SDR amplifies those problems at scale. You still operate the tool; the software just removes the human from the send button.
Single-Channel Outbound Agencies — These firms run email or LinkedIn outreach for you. They write the copy, build the lists, send the sequences, and report on reply rates. The model is well-established and can work, but the output is a campaign, not a system. When the engagement ends, the campaigns stop and the institutional knowledge typically leaves with the team.
Integrated GTM Agencies — These firms run multiple channels — outbound, paid ads, and sometimes content — under one roof. Coordination between channels is tighter than using three separate vendors, though the quality of integration varies widely. Understory, Workflows.io, and GrowthToday operate in this space.
Operator-Led GTM Engineering Firms — The newest category. These firms build the revenue infrastructure — data foundation, signal layer, ICP scoring, routing logic — inside your existing tools, then operate the go-to-market execution from that foundation. The critical distinction is ownership: when a GTM engineering firm builds correctly, what gets built belongs to you. The system lives in your HubSpot or Salesforce instance, your Clay tables, your sequences. It doesn’t disappear when the retainer ends.
10 Questions to Ask Any GTM Engineering Agency
1. What exactly will you build, and where will it live?
This is the most important question, and a vague answer is a red flag. A genuine GTM engineering firm should be able to describe specific deliverables: a data foundation built inside your CRM, enrichment waterfalls, buying signal layers, ICP scoring models, and signal-triggered plays. Ask where each piece lives. If the answer is “our proprietary platform” rather than “your HubSpot and Clay workspace,” you are renting access to their system, not building one you own.
2. Do we own what you build?
This follows naturally from question one. Some vendors structure engagements so that the intellectual property — the tables, the automations, the enrichment logic — exists inside their own infrastructure. If the engagement ends, so does the system. Ask directly: if we part ways after 90 days, what do we walk away with? An honest firm gives you a clear answer. The right answer is: everything, fully documented, inside your own tools.
3. Can you show me a named, verifiable case study — with numbers?
Agencies love to talk about results. Fewer can produce a named client, a named executive willing to speak to the result, a specific dollar figure, and a defined time window. Generic testimonials (“they were great to work with”) and anonymized case studies (“a Series B SaaS company in the logistics space”) are not evidence. Ask for something you can verify.
4. How do you define pipeline, and what are you responsible for?
“Pipeline generated” means very different things depending on who’s counting. Some agencies count every meeting booked, regardless of ICP fit or deal qualification. Others count opportunities created in the CRM. A smaller number count only qualified pipeline — accounts that meet your defined criteria, have a real buying need, and have moved into an active sales stage. Ask how they define it, and ask how they separate their contribution from your team’s existing efforts.
5. What signals do you use to trigger outreach, and how current is your data?
Volume-based outbound is a dying strategy. The agencies still worth hiring are operating from buying signals: a company just raised a new round, a champion moved to a new company, a target account hit your pricing page three times this week, a prospect just added a competing tool to their stack. Ask what specific signals they track, how those signals route into plays, and how often the underlying data is refreshed.
6. How do you handle our existing tech stack?
Any credible firm in 2025 should be comfortable working inside the tools you already pay for — HubSpot, Salesforce, Clay, Instantly, LinkedIn Sales Navigator. If they want to replace your stack, that is often a sign that their model depends on their own tools rather than yours. Replacing your stack also means migration risk, vendor lock-in, and data continuity problems.
7. Where does human judgment sit in your process?
AI-generated outreach at scale is easy to spot. It tends to be plausible but contextually off — the right industry, the wrong framing, a reference to something that doesn’t quite fit. Ask where a human reviews and approves before anything goes out under your name. There is a meaningful difference between “our AI drafts, a human checks” and “we generate and send.”
8. What is your process for the first 30 days?
A firm that cannot describe what the first month looks like in concrete terms — what gets built, what gets tested, what you’ll be able to see — is telling you something. A milestone-based structure is a reasonable expectation: day 30, your first play is live; by day 90, a full set of plays are running. A first-month-free guarantee if the first play isn’t live within 30 days is a reasonable commitment to hold a firm to.
9. How do you report, and on what metrics?
Meetings booked is the most commonly cited metric. It is also the easiest to game by lowering the bar for who gets on a call. Ask whether they report on qualified pipeline, conversation-to-opportunity rates, average deal size of sourced accounts, and closed-won revenue. Ask how often you get reports and whether you have live dashboard access or need to wait for a slide deck.
10. What happens to the system when we stop working together?
The cleanest test of whether you’re buying an asset or renting access. If the answer involves any form of migration, data export, or “we can discuss continuity options,” you don’t own the system. The answer you want: everything is already inside your tools, fully documented, and your team can operate it or onboard a new partner against it without starting from scratch.
Comparing the Leading GTM Engineering and AI SDR Options
1. Frontal
Best for: B2B companies past product-market fit with a focused ICP and a high-value sale — primarily SaaS, but also logistics, manufacturing, distribution, and professional services.
Frontal describes itself as an AI-native revenue partner that builds and operates the go-to-market system behind sales, marketing, and RevOps. The model has two paths: a 90-day build that produces a working Revenue Engine — data foundation, signal layer, and signal-triggered plays — inside the client’s own tools, and an Execution Layer where Frontal operators run outbound, ads, and content from that shared foundation on an ongoing basis.
The differentiator is integration. Outbound, paid advertising, and content run from the same ICP definition, the same enriched data, and the same buying signals, rather than as three separate campaigns with separate reporting. When a target account raises funding, enters a hiring surge, or hits your pricing page, the same signal can trigger an outbound sequence, sync the account into a LinkedIn or Google ad audience, and alert the account owner in Slack — all from a single connected layer.
Frontal has worked with 275+ B2B companies, and Frontal’s Clay expertise is formally recognized through one of four Clay Elite Studio Partner designations awarded worldwide. Their case studies are named and public. For AirOps, Frontal generated $7.83 million in qualified pipeline and $1.52 million in closed-won revenue over 10 months, with no new SDRs hired, and the full system built inside AirOps’ existing HubSpot instance. Teikametrics closed $360,000 in annualized contract value in the first 90 days. Design Pickle went from roughly 10 demos per week to 58 booked in a 14-day period.
The ownership model is explicit: everything built in the 90-day engagement — the Clay tables, the enrichment waterfalls, the play automations, the dashboards — is documented inside the client’s own tools. The system stays when the engagement ends.
Frontal commits to shipping a client’s first working play within 30 days, and backs that with a first-month-free guarantee if it doesn’t happen.
What they don’t do: Cold calling. They are direct about it.
2. Understory
Best for: B2B companies looking for integrated demand generation across outbound and content, with a strategy-first approach.
Understory positions itself as a full-funnel GTM partner with a focus on mid-market and enterprise B2B. Their work typically includes ideal customer profile development, account-based marketing strategy, and multi-channel execution. They tend to run well for companies that need structured GTM planning alongside execution, rather than teams that already know exactly who they’re targeting and need the engine to run.
3. Workflows.io
Best for: RevOps-heavy organizations that want automation consulting alongside go-to-market execution.
Workflows.io focuses on the automation and systems layer — building workflows across CRM, enrichment, and outbound tools that reduce manual work for revenue teams. Their model is closer to implementation consulting than managed execution, which suits companies that want to own and run the system themselves after a structured build.
4. GrowthToday
Best for: Early-stage companies testing outbound channels before committing to a full GTM infrastructure build.
GrowthToday operates in the outbound-first space, with a focus on helping companies establish their first repeatable outbound motion. The model is simpler and lower in investment than a full GTM engineering engagement, which can make sense at the right stage.
5. Artisan
Best for: Companies that want to automate outbound prospecting without a large headcount investment, and are comfortable operating the tool themselves.
Artisan is an AI SDR platform built around a software agent — Ava — that handles prospecting, list-building, and email sequence execution automatically. It is a tool, not a managed service. The output depends heavily on what you put in: your ICP definition, your value proposition, your existing data quality. It can work well for companies with a clear target market and an established outbound process who want to reduce manual SDR work. It is not a substitute for the underlying revenue infrastructure, and it does not fix data or signal problems.
6. 11x
Best for: High-volume outbound programs where automation coverage matters more than deep personalization.
11x is an AI SDR platform with a similar positioning to Artisan — AI-driven prospecting and outreach at scale. The platform is built for volume and can move fast. Like all AI SDR tools, it operates on top of your existing data and ICP work rather than replacing it.
The Honest Comparison
| Frontal | Integrated Agencies | Single-Channel Outbound | AI SDR Tools | |
| Builds inside your stack | ✓ | Varies | Rarely | No (own platform) |
| You own what gets built | ✓ | Rarely | No | No |
| Connects outbound + ads + content | ✓ | Sometimes | No | No |
| Signal-triggered plays | ✓ | Sometimes | Rarely | Sometimes |
| Named, verifiable case studies | ✓ | Varies | Varies | Varies |
| Human judgment in the loop | ✓ | Varies | Yes | Rarely |
| Reduces headcount dependency | ✓ | Adds vendors | Adds vendor | Adds tool |
What the Right Agency Looks Like
The agencies worth hiring in 2025 share a few traits regardless of category: they can name the clients they’ve helped, they define results in terms of qualified pipeline and closed revenue rather than open rates and meeting volume, they build inside your tools rather than theirs, and they can describe the first 30 days in concrete terms with milestones attached.
The questions above are designed to surface exactly those traits — and to expose the ones who can’t answer them cleanly.
Revenue leaders who work through all ten will come away with a clearer picture of what they’re actually buying: a short-term campaign, a rented system, or a durable piece of go-to-market infrastructure that compounds over time.
This article was produced for editorial purposes and does not constitute an endorsement. Company details, partner statuses, and case study figures have been verified against publicly available sources as of publication.
