Cold email outreach: build it in-house or outsource it?

With AI, anyone can now write and send cold emails in seconds. Let's be honest: we all suffer for it. Our inboxes are full of bad, interchangeable emails.

The point is: cold email outreach ≠ cold email outreach. Few sales disciplines make success as hard to reach as this one.

Here is how I run cold email outreach, why I do it this way, and what came out of it.

The devil is in the details

If you have never sent an email sequence, search YouTube for "cold email outreach B2B SaaS" and you will find plenty. On its own, none of it is rocket science:

1. Size the market: I need to know how big my target market is, meaning roughly how many people I want to reach. I double that number, because every cold email should get a follow-up. That tells me how many emails go out per month and how many mail accounts I need. Example: 20,000 recipients x 2 = 40,000 emails. Spread over eight months, that is 5,000 emails a month.
2. Sending domains: Next you need several sending domains, so-called satellite domains. Many people fail right here. The number depends on volume. Example: 5,000 emails a month over 20 working days is 250 emails a day. A single sender should send no more than 15 a day, ideally 5–10. At 15, that makes 17 senders. With 2–4 active senders per domain (depending on daily volume) and another 2–4 in rotation, we end up with 6 domains.
3. Create the senders: Then the senders are set up. They rotate while the campaign runs.
4. Set up the mailboxes: Because they add up very quickly, you need a tool or provider to set up the mailboxes, for example Scaledmail.
5. Sequencer: Then comes the email sequencer. I recommend Instantly, for example.
6. Deliverability: Domains and mailboxes have to be "warmed up" first, otherwise your emails land in the recipient's spam folder very quickly.

Where expertise comes in

• Audience and data: This is where it gets trickier, though AI and tools like Clay make it doable. The data has to be clean and verified. What matters most is relevance, in content and in timing. Someone just changed jobs? Nice, that is what we open with. A company is hiring? Perfect hook. There are dozens of signals like these. The hardest part is getting hold of the data in the first place (scraping and modelling). It can also make sense to build lead scoring at this stage.
• Copywriting: Personalisation that does not sound like a run-of-the-mill sales pitch or AI slop. The first email usually needs several angles, meaning hooks or use cases per persona. The follow-up then has to build on them.
• Testing and optimising: A/B tests, analysis and adjustments while the campaign is running.
• Legal (GDPR and German competition law in B2B): You may receive a cease-and-desist letter or something similar. Be prepared for that before you start, and put the cost of settling it into the campaign budget.
• Inbox management: With this many accounts, you need proper inbox management. There are dedicated tools for it, which again cost money.
• Integration: I strongly recommend deciding before launch how replies reach the sales team: that someone replied, and how (interested, meeting, not interested, wrong person and so on). As a long-time HubSpot person, I always build this as an integration or API (custom app) straight into HubSpot. Workflows then notify the account owner, who can call or reply right away without losing time.

Bottom line: Many companies try to run cold email outreach on the side. They realise it is a lot of work, look for shortcuts and end up not doing it properly. The result: wasted potential, poor numbers, burnt money and put-off prospects.

In-house or outsource?

	In-house	Outsourced (agency)
Getting started	Complex setup with many pitfalls and a steep learning curve	Battle-tested infrastructure, fast start
Experience	Only your own data, few or no benchmarks	Experience from a great many campaigns and industries
Knowledge	Full control, the knowledge stays in the company	Dependency, part of the knowledge sits with the partner
Coordination	Short paths, quick changes, maximum flexibility	The agency does not know your product, offer and market as well as you do. That takes time and a few iterations.
Effort	Ties up time and people your core business needs	Custom integrations, setups and support
Cost	Cheaper in the long run	Expect €4,000–6,000 a month for the agency, plus tools and domains

My take

I like to hand complex, highly specialised work like this to specialists. It saves me time and nerves and improves my odds.

Especially for startups from around €1M ARR that still have few FTEs and little outbound experience, I think it makes sense to outsource this first. Later you can consider bringing it in-house, for example if you want to run an always-on setup.

My partner of choice: GWD

I have worked with Tom, the founder of Grundwerk Digital, three times now, in different roles: for my own business, as a freelancer and as an employee.

Here is a cut from our latest collaboration with GWD at Famedly:

Results (an honest look)

For me as a solo consultant, the investment did not really pay off. My volume was low, but the setup costs at GWD and for the tools (Instantly, domains and so on) were still high.

In B2B SaaS it looks different. At Famedly we got far better results than for my own business. A few numbers:

• 1,468 replies
• 59 sales opportunities
• 7 campaigns
• 3.5 months live
• Return on pipeline: 3.26x

If you are wondering about the return on investment, meaning return on ARR: let's say that in the pilot it still had room to grow. Not because GWD did a bad job, but because we had a lot to learn internally. Our setup simply was not good:

• At first, replies did not reach the CRM automatically.
• Then we took too long to respond.
• And we started with a weak offer, or rather a weak angle.

What I learned working with GWD

• Offer, angle and timing matter enormously.
• Technical setup and response time have to be right from day one.
• Quality beats volume. But volume scales. In the end you need both.

Conclusion and recommendation

• Unless you want to run cold email outreach permanently in always-on mode, I think outsourcing makes a lot of sense from around €1M ARR. Always-on needs a large market to begin with, by the way, and for many specialised B2B companies that alone is a real challenge.
• For very small companies and solo founders (under €1M ARR), the manual route is far wiser: low volume, very high quality content. That is how you learn what can scale in the first place, meaning which use cases, angles and offers really work.