Google App Ads Expert: London Founder's Guide

Finding someone in London to run your Google App Ads feels like it should be easy. The city's crawling with agencies. But finding someone who won't just burn through your seed funding with rubbish results? That's a different game entirely. Most 'Google Ads experts' have only ever run Search or Shopping campaigns for plumbers and online shops. They see "App Campaign" as just another button to press in the dashboard. This is a fatal mistake.

App campaigns, or UAC (Universal App Campaigns) as they used to be called, are a completely different beast. They're driven by machine learning that relies on a constant feed of high-quality creative assets and clean conversion data from your app's SDK. A generalist digital marketer won't understand the nuances of Firebase events, SDK integration, or the relentless creative iteration needed to scale. They'll treat it like a search campaign, get you a load of cheap installs from users who open the app once and then delete it, and then wonder why you're not making any money. You need a specialist, and this is how you find one without getting rinsed.

So, what makes finding a real App Ads expert in London so difficult?

The problem is the sheer noise. London's tech scene, especially around Shoreditch and Old Street, is saturated with agencies that claim to do everything. They're jacks of all trades and masters of none. They'll have a slick website talking about "data-driven strategies" and "holistic growth," but when you push them, their experience with actual app user acquisition is paper-thin. They might have run a campaign for a big brand's app once, where the goal was just "presence" and "awareness," which is worlds away from the hard-nosed performance marketing a startup needs to survive.

You have to cut through that fluff. An expert knows that Google App campaigns are less about keyword bidding and more about creative asset management and audience signalling. The algorithm does the heavy lifting on targeting, but it's only as good as the inputs you give it. The expert's job is to feed the machine with the right videos, images, and text, and to tell it which in-app actions (like completing a tutorial, starting a trial, or making a purchase) matter most. They understand that an install is just a vanity metric; the real goal is acquiring a user who will eventually pay you. Many so-called experts don't grasp this and will celebrate a low Cost Per Install (CPI), even if none of those users ever convert. It's a classic rookie error.

That's why you need to be ruthless in your vetting. You're not just hiring a campaign manager; you're hiring a strategist who understands the entire app monetisation funnel. To do that, you first need to know what 'good' actually looks like. I've seen countless founders get taken for a ride because they didn't have a baseline for performance. They were sold on vague promises because they didn't know what specific results to demand. Before you talk to anyone, you need to understand the numbers.

For a deeper look into the general agency landscape and what to watch out for, our guide to vetting London ad experts provides a solid foundation before you start your search.

What do good app campaign results even look like in the UK?

This is the million-pound question, isn't it? The answer is, it varies. But not as much as some agencies would have you believe. While every app is different, there are definitely benchmarks. Anyone who tells you "it's impossible to say" is either inexperienced or trying to avoid being held accountable. Based on the campaigns we've run, you can get a pretty good idea of what to aim for.

For example, we ran a campaign for an events and sports app where the main goal was getting signups. We managed to bring in over 45,000 signups at a cost under £2 per signup. That was a huge success because the lifetime value of that user was significantly higher. For a more specialised app, the costs can start higher but a specialist can bring them down dramatically. For instance, for one medical job matching SaaS client, we took their Cost Per User Acquisition from an unsustainable £100 all the way down to just £7 using a combination of Google and Meta Ads. These are the kinds of numbers a true specialist can achieve.

To give you a clearer picture, here’s a rough breakdown of what you might expect for Cost Per Install (CPI) across different app categories in the UK. This isn't gospel, but it's a realistic starting point based on our experience.

But remember, CPI is only the beginning of the story. A good expert will immediately shift the conversation to Cost Per Action (CPA). What does it cost to get a user to complete the onboarding? To start a free trial? To make their first purchase? These are the metrics that actually correlate with revenue. If a potential agency fixates on CPI, it's a massive red flag. They should be obsessed with your business model and how to acquire users who will contribute to your bottom line.

How do I spot the pretenders from the real pros?

This is where you need to become a skilled interrogator. You need a process. Don't just have a casual chat; go into every meeting with a clear plan to qualify them. It’s not about being rude, it’s about protecting your business. Here’s a simple flowchart of the process we recommend to founders.

The most critical stage here is Step 2: Case Studies. I can't stress this enough. If an agency cannot show you detailed case studies from other app campaigns, they are not the right fit. It doesn't matter how impressive their other work is. I remember one campaign we worked on for a medical job matching app where we reduced their Cost Per User Acquisition from £100 down to £7. That's the kind of specific, tangible result you're looking for. Ask them to walk you through a campaign. What was the starting CPI? What was the target CPA for a trial? How did they test creatives to bring that cost down? If they get vague or defensive, it's a huge red flag that they don't really have the expertise. Tbh if someone asks us for references after they've already reviewed our case studies, it signals they really don't trust us and that'll probably continue.

During the discovery call (Step 3), here are the killer questions you need to ask:

1. "Can you walk me through your creative testing process for Google App Campaigns?"
This is the most important question. A pro will talk about building a 'creative matrix' with different angles, hooks, and calls to action. They'll mention testing various formats (video, image, HTML5), aspect ratios (16:9, 1:1, 9:16), and iterating based on performance data in the asset report. A pretender will say something generic like "we test different ads to see what works." The devil is in the detail.

2. "How do you approach bidding? Which in-app events would you recommend we optimise towards for our app?"
This tests their strategic thinking. Their answer should involve asking you questions about your monetisation model. They should talk about starting with optimising for installs (tCPI) to gather data, then quickly moving to optimising for actions (tCPA) like 'trial_started' or 'first_purchase'. If they can't have this conversation, they don't know what they're doing.

3. "What was the biggest challenge you faced scaling an app campaign, and how did you overcome it?"
This question reveals their real-world experience. A good answer might involve dealing with creative fatigue, troubleshooting SDK tracking issues, or navigating policy restrictions in a tricky vertical like FinTech. A bad answer is a generic one about "finding the right audience."

By arming yourself with this knowledge and process, you shift the power dynamic. You're no longer a founder hoping to find a good supplier; you're a discerning buyer conducting a rigorous evaluation. For a complete breakdown of the hiring process, from shortlisting to onboarding, our comprehensive hiring guide for Google App Ads experts is an invaluable resource.

But can I even afford this? Calculating your potential ROI.

This is where many founders get nervous. Hiring a specialist sounds expensive. And yes, they will cost more than a generalist agency. But the real question isn't "what does it cost?" but "what is the return?". Paying a cheap agency to get zero results is infinitely more expensive than paying a specialist to acquire profitable users.

To understand what you can afford to spend, you need to know your numbers. Specifically, your Customer Lifetime Value (LTV). If you don't know this, stop everything and calculate it now. It is the single most important metric for your business.

Here's a simple way to think about it for a subscription app:

1. Average Revenue Per User (ARPU) per month: Let's say your subscription is £9.99/month.
2. Gross Margin %: After app store fees (let's say 30%), your margin is 70%.
3. Monthly Churn Rate: What percentage of subscribers do you lose each month? Let's say it's 8%.

The calculation is: LTV = ((ARPU * Gross Margin %) / Monthly Churn Rate)
LTV = ((£9.99 * 0.70) / 0.08) = (£6.99 / 0.08) = £87.38

This means, on average, each new subscriber is worth £87.38 in gross margin to you. A common rule of thumb is that your Customer Acquisition Cost (CAC) should be no more than 1/3 of your LTV. In this case, that means you can afford to spend up to £29.12 to acquire a new subscriber. If you know that 1 in 10 users who start a free trial convert to a paid plan, you can therefore afford to pay up to £2.91 for each free trial signup.

Suddenly, as mentioned, that £2 cost per signup we achieved for that events app doesn't just sound good, it sounds incredibly profitable. This is the math that allows you to invest in paid acquisition with confidence. An expert will not only understand this, they will build their entire strategy around these numbers. To help you play with your own numbers, here's a simple interactive calculator.

Understanding these metrics is not just for your own benefit; it's also a powerful vetting tool. When you can talk confidently about LTV:CAC ratios and your target CPA for a subscriber, you immediately signal to any potential partner that you're a serious founder who understands the economics of their own business. It forces them to raise their game and engage with you on a strategic level, not just as another client to whom they can sell a monthly retainer. For those wanting to really get to grips with the numbers, our guide on calculating paid ads ROI offers a much deeper look, which is valuable for any tech founder in London.

Your Action Plan: The Vetting Checklist

Alright, let's pull all of this together into a concrete plan. When you're ready to start talking to potential experts or agencies in London, use this table as your guide. It's your cheat sheet to making a smart, informed decision and avoiding the charlatans.

I've detailed my main recommendations for you below:

It's time to stop gambling and start investing

Hiring an agency or consultant to run your app's user acquisition is one of the most significant decisions you'll make as a founder. Getting it right can be the catalyst for explosive growth. Getting it wrong can mean burning through your runway and ending up with nothing but a handful of worthless vanity metrics. The London market is a minefield, but it's also home to some incredible talent if you know how to find it.

The process I've outlined isn't easy. It requires you to do your homework, to learn the language of app marketing, and to be disciplined in your vetting. But the alternative is far worse. By taking a strategic, evidence-based approach, you dramatically increase your chances of finding a genuine partner who can help you scale profitably.

It's not just about setting up an ad and hoping for the best. It's about building a scalable, repeatable engine for user growth. It's about understanding the intricate dance between creative, data, and machine learning. This level of specialisation is complex and time-consuming, and frankly, as a founder, your time is better spent working on your product and overall business strategy.

If you've read this far and feel a bit overwhelmed, that's normal. This is complicated stuff. If you'd like an expert second opinion on your current strategy or help in navigating this process, we offer a completely free, no-obligation 20-minute strategy session where we can audit your current efforts and give you some actionable advice. It's a chance to see the kind of expertise you should expect from a true specialist. Feel free to get in touch to schedule a call.