Sascha Lang has lived through more growth cycles than most founders ever will.
Seven years ago he started his first company. That company got into Y Combinator. Y Combinator meant one thing: scale fast or fall behind. Warm outreach and personal connections ran out quickly. Cold email became the channel. Cold email led him to Smartlead.
Two and a half years ago, that first startup was acquired. Sascha Lang walked away from it and into his next chapter: a cold email agency built to help other companies do what he had spent years learning to do himself.
Then, a year ago, the pull of the startup world came back. He paused the agency, co-founded another company, and stepped away from cold email operations entirely.
It did not last long.
"From a family point of view, I have two small children. The startup life was not the one that suited that perfectly. And I really enjoyed having a cold email agency. I like creating new campaigns. What happened over the last year with AI just makes it so much more fun. So I said, let's go back to doing what I actually like doing."
That decision brought him back to cold email. Back to Smartlead. And back to building campaigns for the clients he knows best.
That is Tirvio. A recruiter pipeline engine for US and UK recruiting and staffing firms, built on four years of Smartlead experience, running entirely on API and Claude Code. The same outreach motion that powers 100+ recruiting firms through Vakanzio, now run as a done-for-you performance engine for recruiting firm owners who want a predictable flow of qualified hiring-client meetings.
Sascha Lang, founder of Tirvio, has been running cold email on Smartlead for four years across two agencies and a Y Combinator startup. Here is what that experience has produced:
Sascha Lang did not set out to become a recruiter pipeline specialist. He set out to build a startup.
When that startup got into Y Combinator, the pressure to grow fast became the defining constraint of his work. Warm outreach dried up. Personal networks ran out. Cold email was the next channel, and he learned it the way engineers learn anything: by going deep, iterating fast, and building systems around what worked.
That first startup ran on cold email until it was acquired two and a half years ago. The exit created a question: what next?
The answer was obvious in hindsight. He had spent years mastering the most repeatable B2B growth channel available. Other companies needed exactly what he knew how to do. So he co-founded a cold email agency, ran it for two and a half years, expanded into cold calling for a period, and built a client base of startups and growing businesses that needed pipeline.
Then came the detour. Another startup, another founding team, another pause on agency life.
"A year ago we decided to go back into the startup world, where we founded another startup. That's also when we paused our agency. Then from a family point of view, I have two small children, and the startup life was not the one that suited that perfectly."
The pull back to agency life was not just personal. It was professional. What AI has done to cold email over the past year made the craft genuinely more interesting, not less.
"What happened over the last year with AI just makes it so much more fun and you can be more creative and build cool campaigns."
Tirvio is the result of that decision. A recruiter pipeline engine for US and UK recruiting and staffing firms, built on four years of Smartlead experience and the same outreach motion already running at 100,000 sends per week in production.
The answer starts and ends with the API.
Sascha Lang comes from a technical background. He runs his entire operation on Claude Code. For someone who thinks and works that way, a platform without a proper API is not a platform worth considering.
"Ever since Smartlead was there, the one thing that made it stand out was it was API first. With someone coming from a tech background, it was always the obvious first choice. These days since anything I do is running on Claude Code, anything without an API doesn't work for me. So Smartlead is the obvious choice."
That has not changed across four years, two agencies, and a Y Combinator startup. The API is why he started. It is why he stayed.
The API
Non-negotiable. Everything runs through it. Campaigns are built, managed, and monitored via Claude Code. The interface exists to check statistics visually. The API is where the work actually happens.
"I will always say the API. That's the number one thing I really love. After a year of solely using Claude Code for anything I do, I almost feel offended if I have to go into the interface to do something. But since you don't force me to do that, just keep going."
Pre-Warmed Inboxes
Speed matters in agency work. When a new client comes on or a campaign needs to launch fast, waiting weeks for inboxes to warm is a problem. Smartlead's pre-warmed inbox option removes that bottleneck entirely.
"The possibility to buy pre-warmed inboxes because every now and then you're in a hurry and you need something in one place. That's really helpful and it works super well."
The Reply Agent
Coming back to the platform after a year away, the AI reply agent was the feature that impressed him most. At high reply volume, having an AI layer that handles triage changes the economics of inbox management entirely.
"The reply agent and the AI side of that is really helpful, especially when I have a lot of replies coming in. That's something I was just really impressed by."
SmartSenders and Placement Tests
Inbox placement uncertainty is one of the most expensive problems in cold email. You test messaging, get no results, and eventually realise the inboxes were burned the whole time. SmartSenders and placement tests make that problem visible before it costs a campaign.
"The placement tests are always the one thing that's really a big problem if I'm not certain if I'm actually landing in the inbox. You test messaging and just don't get results, and then you figure out the inboxes are burned. That's always been a big thing I love and always really like to use."
Warmup Pools
Inbox quality is ongoing, not a one-time setup. The quality of the warmup pool determines whether inboxes stay healthy over time, which determines whether emails reach the primary inbox month after month.
"The different warmup pools, to make sure my inboxes get continuously properly warmed up and stay in a good state."
Demo Boutique, Recruiting: 35% Positive Reply Rate, 5 Contracts in 3 Weeks
Demo Boutique is a boutique recruiting firm. The strategy was hyper-targeted: scrape job postings, match them against the candidates already in the client's internal applicant tracking system, and write emails that referenced a specific candidate match for each prospect.
Every email was individual. Every message was built around a real signal. The results reflected that precision.
"We were creating messages that were a really high fit and we could already tease a candidate they had. I think they had something along 35% positive reply rates and almost 7.5% reply rate. In three weeks we were able to book them five new contracts."
The client had to stop. Not because the campaign failed. Because five new contracts in three weeks was more than a boutique shop could fulfill.
"At that point we unfortunately had to stop because they couldn't fulfill anymore. It was like a small boutique shop, but it worked really well."
Kravo, DACH Recruiting Firm: 6 New Clients in 3 Weeks
Candidate-profile outbound to hiring companies in the finance and sales and business development niches, run end to end: list building, campaigns, reply handling. The same motion Tirvio now runs for US and UK recruiting firms.
Sascha Lang has run startups. He knows what good support looks like because he has had to build it himself. Smartlead's support response has surprised even him.
"I can either on Slack send a message and then mostly your founder directly messages me back. Even without tagging him. He's so active. That's insane. But then also we have a dedicated Slack channel. If I have a message there, there's like two or three people taking care of me all the time, coming back to me immediately. As someone who's run a startup himself, I almost don't even get how good you do that."
"Just go to the university, take the one-on-one course. There are two or three from actual agency owners as well. Just do what they tell you and follow it. Sometimes it feels like not the right move, but all the times it is. Trust the process. Keep sending cold email every day even when it doesn't work. I know it works. It's changing and it's getting harder, but it does work and it's a process. You have to learn it, but keep doing it and trust the information that Smartlead gives you. And then you will have success."
You can replicate these results when you treat cold outreach as a system rather than a guessing game.
Start by fixing deliverability with Smartlead's automated warm-up and warmup pools. Use SmartSenders and placement tests to confirm your emails are reaching the primary inbox before scaling volume. Build your campaigns around real signals the prospect actually recognises, not generic template fields.
The difference between a 7% reply rate and an industry average is not better copy. It is tighter targeting, infrastructure that holds at volume, and personalisation built on something specific and true.
Ready to build your own outbound engine? Start your free trial on Smartlead and use the same infrastructure Sascha Lang has run on for four years. Review the complete Smartlead pricing breakdown to see how the model scales as your outreach grows.
Join us to elevate your outreach!
Founder, StackOptimise
Smartlead's combination of automation, unlimited inboxes, and easy campaign management has completely transformed how we run cold email campaigns.
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Founder, Cold Email Hackers
We have about 15 companies and we use Smartlead for all of them.
Founder, DutchSave Media
One of the things I love about using Smartlead is the deliverability feature. If they landed in the bounce or spam folders, we could resolve this quickly.
Co-Founder, Growth Today
I want to continue to use Smartlead to make operations more seamless - the plan is to bring more clients here and build more SOPs.
Founder, FueltoFly
Smartlead listens to the agencies and customers and builds according to what people want, that has really made things easier for us.
Founder, OutboundSync
We build an infrastructure product, and OutboundSync communicates with Smartlead itself. I love the webhook and API. They're really well done and keep getting better.
Founder, Axoleads
With SmartDelivery, you can put all of that in the hands of the tool. It ensures your emails land in inboxes, and by running a simple test, you can see if you're hitting the mark.
Founder, Claygen
Deliverability is the cornerstone of cold email outreach. You could have the best email copy in the world, but if no one is seeing it, it's useless. I really love the feature where you can actually give client accesses to your clients.
Co-Founder, Cymate
I do not want to switch to another software. Pick a solution you trust, stick with it, and keep refining your copy.
CMO, Avalanche Capital
Managing large volumes of emails through multiple inboxes used to be a logistical nightmare. With Smartlead, the process is seamless. We book thousands of discovery calls through cold emails. These campaigns are generating leads at a scale we never thought possible.
Founder, Growth Engine X
We came for the unlimited inboxes, and we stayed for the API. 1.5M cold emails/month, 7,767+ inboxes managed.
Head of Community & Ecosystem, TxtCart
You cannot replace having 10,000 touches with potential clients. When you have that much distribution and reach, you really start to see incredible results. The simplicity of Smartlead made all the difference. It doesn't require you to be a technical wizard.
Founder, Hyperke
Smartlead has been a game-changer for us. It increased our appointment volume, improved ease of use, and offered valuable features. 80% increase in appointments/month, peak of 276 appointments in a single month.
Founder, Kinetyca
Smartlead has been our cold email backbone from day one. The platform evolves constantly, keeping pace with how deliverability and personalization need to work today. 21% overall reply rate, $175K in 4 months for multiple B2B clients.
Founder, Reachflow
Smartlead is centered around deliverability and constantly evolving. Their API is not like any other platform. Smartlead covers all our needs. The focus on core features like deliverability and API integration is unmatched.
CEO, Halfwarm
Our approach to crafting conversational emails led to reply rates that many of my peers thought were unattainable.
Co-Founder, letstrike
We've grown on zero capital, zero marketing, purely cold emailing - and that's the story we love to tell. The best approach is no approach if you can't handle domain meltdown. The second best is something like Smartlead that's built from the ground up for deliverability at scale.
Founder, Fenixtal
Smartlead's white-labeling and automation let us punch above our weight. The 12M euros sales potential? That's what happens when you combine human creativity with Smartlead's precision.
Co-Founder, Digital Creativs
Nine out of 10. Ninety percent of our clients are on Smartlead unless they come in with an existing setup. That's the default.
Co-Founder, BuildingReach
At the end of the day, you have to take a bet on one tool or another. It was a no-brainer taking that bet on Smartlead. We had to even turn down the volume of our marketing campaigns - Smartlead was capable of driving more volume than our sales team was able to fulfill.
Founder & MD, Prospectiv
Since starting the business in January of this year, we've already generated $200K in sales exclusively from cold email. Smartlead has been central to our operations and has exceeded our expectations.
Founder, Growthlynk
There's so much stuff built on top of it. I would be dead if I had to rebuild it with another tool. I can manage hundreds of senders easily. I can send hundreds of thousands of emails.
Founder, Corebits
The platform's HubSpot integration, real-time Slack updates, and advanced campaign customization have been game changers for our business and our clients'.
Founder, Apex Ascension
From day one, we've never used anything else.
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