Data-driven growth for ambitious brands on Amazon and beyond

We run marketplace accounts against contribution margin, not return on ad spend. Flat fee, weekly numbers, and a straight answer when something is not working.

Case study · Health & Household

How we turned a stalling account
into a category leader

Volara Nutrition was spending about $18,400 a month on Amazon ads and growing revenue 8% a year. Six products carried the business and were getting 22% of the budget. Nobody inside the company could tell us which campaigns were responsible for either number.

We rebuilt the account around what actually earned money, cut 112 campaigns down to 22, and fixed the three listings that were losing conversions before we bought them any more traffic. Nine months later the numbers look like this.

+68% Revenue, year over year
31% Lower ACoS
3.4x DSP return on ad spend
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Volara Nutrition product range

Our results speak
for themselves

Sentinel Digital has grown through word of mouth, on the back of what our clients went on to do. Their numbers are the only pitch we have.

Priya Raghunathan

2 reviews · US

★★★★★ 06/04/2026

They told us to stop selling things

Our first month with Sentinel, they came back and said nine of our products were losing money on every unit and we should stop advertising all of them. That is not what an agency paid on ad spend tells you. Nine months on, revenue is up 68% on a smaller catalogue and I finally trust the reporting.

Date of experience:
06/04/2026

Daniel Okoro

1 review · UK

★★★★★ 03/18/2026

First Christmas I did not spend on the phone to freight

We sell cookware, so our year is really six weeks long. Sentinel built the Q4 plan in June and worked backwards from the shipping cutoff. We did not go out of stock for the first time in four years, and our January rank held instead of falling off a cliff.

Date of experience:
03/18/2026

Hannah Vogel

1 review · US

★★★★★ 02/09/2026

Annoying and correct

We had tried Walmart in 2023, done about two grand a month, and written the channel off. Sentinel went back through what we had actually done and showed us we had never run it properly. Nine months later a third of our marketplace revenue is off Amazon. Worth the mild embarrassment.

Date of experience:
02/09/2026

Marcus Feld

1 review · UK

★★★★★ 11/21/2025

The audit paid for itself in week three

We booked a one off audit because our accountant could not reconcile Amazon’s numbers. They found $9,400 in unclaimed reimbursements and a dimension error that had been overcharging us since 2023. Then they read a year of our return comments and worked out our bag was splitting in transit, which was costing us more than the fees were.

Date of experience:
11/21/2025

Jen Castellano

3 reviews · US

★★★★★ 09/30/2025

Weekly call, 25 minutes, actual decisions

I have worked with four agencies and this is the only one where the call ends with a decision rather than a deck. Same five numbers every Tuesday. If something is not working they say so before I have to ask, which sounds like a low bar until you have been on the other kind of call.

Date of experience:
09/30/2025

Tomasz Adamek

1 review · DE

★★★★★ 08/12/2025

Good on the detail, honest when a test fails

They ran a DSP audience for us that did not work and shut it down at about two and a half thousand dollars rather than letting it run to protect the story. The next one returned over 3x. I would rather have an agency that stops things than one that never admits a test went nowhere.

Date of experience:
08/12/2025

Reviews collected from clients at the end of each engagement quarter.

We came to Sentinel after two agencies that both sent beautiful monthly decks and neither of which could tell me what a unit actually earned us. The difference here is that the first conversation was about our cost of goods, not our ad spend. They rebuilt the account around six products instead of twenty four, and the six that mattered got the budget the other eighteen had been quietly eating. I still get a short note every Tuesday telling me what changed and what they are doing about it. Three years of agencies, and that is the thing I would not give up.

Priya Raghunathan VP Growth · Volara Nutrition

Big moves start with the right team on your side

Hands-on
Leadership

Everyone who owns an account here has run a marketplace P&L with their own money in it. That is the only qualification we insist on, because it changes what a person notices in a settlement report.

It also changes what they are willing to tell you. Our strategists have recommended clients stop advertising a product, cut a range, and in two cases spend less money with us.

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Your brand’s
Growth Partner

There is no single playbook that survives four categories. We plug into your team and work the account the way an in house hire would, with the same access and the same visibility.

A shared Slack channel, a project board you can see, and a 25 minute call every Tuesday that ends in a decision rather than an action item.

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Data-first
Operators

Every recommendation traces back to a number you can click into. SentinelIQ joins your advertising, sales, and fee data to your cost of goods, so nothing we claim has to be taken on trust.

When a test fails it goes in Tuesday’s note before you have to ask about it. We have shut down our own campaigns at $8,000 rather than let them run to protect a story.

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Custom-built
Solutions

Some brands want the whole account run. Some want one channel built while their own team keeps the rest. Both are fine, and the scope gets written around what you actually need.

The standard does not change with the size of the retainer. Protect the margin, find the thing nobody is looking at, and say so early when it is not working.

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We’re the Amazon operators standing guard over your brand’s growth

Sentinel Digital is a marketplace agency run by people who sold on Amazon with their own money at stake. We are eight specialists, we take a limited number of accounts, and we say no when the calendar is full.

Fresh takes on the latest algorithm shifts

Let’s discover what’s possible for your brand

Thirty minutes, no deck. Bring your ad spend and roughly what your cost of goods looks like.

You get a short written note afterwards with two or three things worth doing, whether or not you ever hire us. Several brands have taken that note and done the work themselves.

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