Quick answer
Growth Engine X and Outbound Pros are both cold-outbound agencies that obsess over deliverability, but they fit different buyers. Growth Engine X is a New York-based, Clay-native cold email and full-cycle sales shop (10-49 employees, founded by Eric Nowoslawski) that pairs AI-assisted personalization with interest-based follow-up calls and project-based pricing. It suits teams that want a builder-led, Clay-and-Smartlead-heavy program with calls layered on top. Outbound Pros is a founder-led, deliverability-first managed-outbound agency that runs email + LinkedIn as one coordinated sequence on dedicated, owned domains, with replies in the Primebox unified inbox, transparent live reporting, and flexible retainer-plus-performance pricing. If you're a B2B or SaaS team that wants senior operators running a unified email-and-LinkedIn motion on owned infrastructure with predictable retainers, Outbound Pros is the stronger fit.
I'm Jānis, founder of Outbound Pros. We run 36 active outbound campaigns and have shipped 200+ since we started. Growth Engine X is a genuinely sharp, technically credible shop, its founder is well known in the cold-email and Clay community, so this is the honest comparison: what each does well, where each wins, and which buyer should pick which. If you're weighing us against Growth Engine X, this is the straight answer, not the sales-deck one.
Growth Engine X vs Outbound Pros: At a Glance
| Dimension | Growth Engine X | Outbound Pros |
|---|---|---|
| Best for | Teams wanting a Clay-native cold-email program with interest-based calls layered in | B2B/SaaS teams wanting deliverability-first, unified email + LinkedIn managed outbound |
| Model | Builder-led cold-outbound shop | Founder-led, senior-operator managed service |
| Channels | Cold email, LinkedIn sourcing, interest-based calls, multi-touch sequences | Email + LinkedIn, unified inbox (Primebox) |
| Company size | 10-49 employees | Lean senior team, 36 active campaigns |
| Pricing | Project-based pricing | $1.5K-$10K/month; hybrid retainer + per-meeting available |
| Infrastructure | Warmed domains/inboxes, SPF/DKIM/DMARC | Dedicated, owned domains per client; documented DNS/warm-up |
| Deliverability focus | Core stated specialty | Core specialty, 85-95% inbox placement target |
| Reporting | Real-time metric tracking, A/B testing | Live dashboard + interpreted monthly report (volume/quality/funnel/ROI) |
| Stack | Clay, Smartlead, Apollo, GMass | Salesforge, Clay, Leadsforge/Apollo, Agent Frank (optional AI SDR) |
| Location | New York, New York, USA | Remote, founder-led |
What Is Growth Engine X?
Growth Engine X is a B2B cold-outbound agency based in New York that acts as a client's outbound sales engine, founded by Eric Nowoslawski. With 10-49 employees, it specializes in cold email outreach extended through to booked meetings via interest-based calls, and it positions deliverability as a near-sacred discipline, warming up domains, managing sender reputation, and avoiding the fake engagement and mass blasts that trigger spam filters. Its stated services span a deliverability-first mindset, personalization at scale, rapid iteration, and a complete sales pipeline. Pricing is project-based.
Its approach is technical and tooling-heavy. Emails use AI-assisted first lines, LinkedIn-informed openings, and data-empowered copywriting rather than a single "same message" mass send. The team builds campaigns from a basic ideal customer profile, enriches with LinkedIn data and multiple inboxes, configures SPF, DKIM, and DMARC for inbox placement, and iterates continuously with A/B testing of subject lines and copy. It compares and uses tools like Apollo, GMass, Smartlead, and Clay.com, and supports full-cycle execution including interest-based follow-up calls and demo coordination. For a buyer who wants a builder-led, Clay-native cold-email program with calls layered on top, Growth Engine X is a credible choice.
*(Note: at the time of writing, Growth Engine X has no published client reviews on platforms like Clutch or G2, so this profile reflects its stated services and website case studies rather than third-party verified outcomes.)*
What Is Outbound Pros?
Outbound Pros is a founder-led, deliverability-first managed-outbound agency that runs email and LinkedIn campaigns for B2B companies from a single coordinated stack. We run 36 active client campaigns and have shipped 200+ since starting. Instead of an account-management layer between you and the work, you get senior operators who treat cold email as a craft, because deliverability is the difference between a campaign that books meetings and one that lands in spam.
Our stack is modern and AI-native: Salesforge for email + LinkedIn sending (whitelabel tier, with the Primebox unified inbox), Clay for waterfall enrichment and AI personalization, Leadsforge and Apollo for sourcing, and Agent Frank as an optional AI SDR for clients who want it. Every client gets dedicated, owned domain infrastructure with documented DNS and a proper 4-6 week warm-up, plus a live reporting dashboard and a monthly report that interprets the numbers rather than just dumping them. We onboard in roughly 21 days, and typically ramp to 15-30 booked meetings per month by months two and three.
Where Does Growth Engine X Win?
Growth Engine X wins on technical pedigree, Clay-native depth, and full-cycle reach beyond email. Three specifics matter most:
- Founder-led, Clay-native expertise. Founded by Eric Nowoslawski, Growth Engine X is steeped in the modern Clay-and-Smartlead toolset, with data-empowered copywriting and AI-assisted personalization at its core. If you want a partner fluent in that exact stack, it's a strong match.
- Interest-based calls and full-cycle execution. Beyond cold email, Growth Engine X layers in interest-based follow-up calls, demo coordination, and multi-touch sequences. If you want a phone touch woven into the motion, that's a channel Outbound Pros does not run as a core service.
- Rapid, metrics-driven iteration. Growth Engine X analyzes open, click, and reply metrics in real time and continuously A/B tests subject lines and copy to fight campaign fatigue, a disciplined, builder's approach to optimization.
If your priority is a builder-led cold-email shop with deep Clay tooling and interest-based calls layered in, Growth Engine X is the right call, and I'd tell a prospect that directly.
Where Does Outbound Pros Win?
Outbound Pros wins when unified multichannel coordination, owned infrastructure, transparency, and predictable pricing matter more than a calls-included, project-based build. Both agencies are deliverability-obsessed, so the real contrast is in model and channel design.
- Unified email + LinkedIn from one inbox. Email and LinkedIn run as one coordinated sequence, with replies landing in the Primebox unified inbox instead of being split across tools. Growth Engine X uses LinkedIn primarily for sourcing and personalization data; we run it as a live outbound channel coordinated with email, which lifts reply rates and stops leads slipping between channels.
- Dedicated, owned domain infrastructure. Every client gets dedicated, owned domains with documented SPF/DKIM/DMARC and a disciplined 4-6 week warm-up aimed at 85-95% inbox placement. You own the infrastructure, not a shared or rented setup.
- Transparency by default. You get a live dashboard you can check any time plus a monthly report that interprets volume, quality, funnel, and ROI, what we tested, what the data said, what changes next. No black box.
- Senior operators, not a hand-off. You work directly with the people running your campaign. Decisions happen in hours, not through a queue.
- Predictable, flexible pricing. Beyond standard retainers we offer hybrid retainer-plus-performance terms (a base plus a per-meeting fee above a baseline) for clients who want incentives aligned, clearer to budget than open-ended project pricing.
- Defined ramp and cadence. We onboard in ~21 days and typically ramp to 15-30 meetings per month by months two and three, with churn held at 3-5% per month.
Pricing: Growth Engine X vs Outbound Pros
The structures differ more than the headline numbers. Growth Engine X uses project-based pricing, scoped per engagement, which can suit a defined build but is harder to forecast month over month. Outbound Pros runs $1,500-$10,000/month depending on scope, with public tiers around $1,500 (startup), $3,000 (growth), and $5,000 (scale), and, for trust-based accounts, a hybrid model of a $2,000-$3,000 base plus $25-$50 per meeting booked above a baseline.
The practical difference is predictability and alignment. A monthly retainer is easier to budget than project scoping, and the hybrid option lets you tie a portion of spend directly to booked meetings, something a project-based engagement typically won't offer. Neither is "cheaper" in the abstract; they're priced for different buying styles.
Who Should Choose Growth Engine X?
Choose Growth Engine X if you want a builder-led, Clay-native cold-email program, value AI-assisted personalization and rapid metrics-driven iteration, want interest-based follow-up calls and full-cycle execution woven into the motion, and are comfortable with project-based scoping and a US (New York)-based shop.
Who Should Choose Outbound Pros?
Choose Outbound Pros if you're a B2B or SaaS company that wants email and LinkedIn run as one coordinated motion with replies in a single inbox, expects dedicated owned domain infrastructure and an 85-95% inbox-placement target, wants transparent live reporting instead of a black box, and prefers predictable monthly retainers (or incentive-aligned hybrid per-meeting pricing) over open-ended project scoping. If you'd rather work directly with senior operators on a modern AI-native stack, that seals it.
If You're Comparing Options
If you're weighing Growth Engine X against Outbound Pros, the honest test is what your campaign actually depends on. Want a builder-led, Clay-native cold-email program with interest-based calls and project-based scoping? Growth Engine X. Want deliverability-first, unified email + LinkedIn run by senior operators on owned infrastructure, with transparent reporting and predictable pricing? That's Outbound Pros managed outbound, we onboard in ~21 days, run the full stack from sourcing through reply management, and report monthly on meetings booked, reply rate, and ROI. The conversation starts with what you're trying to achieve and whether outbound is even the right channel for it.
Frequently Asked Questions
Is Outbound Pros a Growth Engine X alternative?
Yes. Outbound Pros is a direct alternative to Growth Engine X for B2B cold outbound. Both are deliverability-first agencies, but the focus differs: Growth Engine X is a builder-led, Clay-native cold-email shop that layers in interest-based calls and full-cycle execution on project-based pricing, while Outbound Pros is a managed-outbound service that runs email + LinkedIn as one coordinated sequence on dedicated owned domains with transparent reporting and monthly retainer (or hybrid per-meeting) pricing.
Does Outbound Pros do interest-based calls like Growth Engine X?
No. Outbound Pros is email-and-LinkedIn-first by design and does not run calling as a core service. If interest-based follow-up calls are central to your motion, Growth Engine X is the better fit. If your buyers respond best to coordinated email and LinkedIn sequences, Outbound Pros is built for that.
How much do Growth Engine X and Outbound Pros cost?
Growth Engine X uses project-based pricing, scoped per engagement. Outbound Pros runs $1,500-$10,000/month with tiered packages (around $1,500, $3,000, and $5,000) and an optional hybrid retainer-plus-performance structure, a base fee plus a per-meeting fee above a baseline, for aligned incentives.
Which is better for a B2B SaaS company?
For most B2B SaaS teams, Outbound Pros' unified email + LinkedIn motion, dedicated owned infrastructure, and transparent reporting tend to fit well, especially when predictable retainers matter. Growth Engine X is a strong choice when you want a Clay-native cold-email build with interest-based calls and full-cycle execution layered in.
How fast can each get a campaign live?
Outbound Pros onboards in roughly 21 days, including domain provisioning and the start of warm-up, then typically ramps to 15-30 meetings per month by months two and three. Growth Engine X scopes timelines per project, including domain warm-up and technical setup before launch.