What 'Klaviyo Partner' does and doesn't mean
Partner status means an agency has met Klaviyo's requirements and manages accounts on the platform. It is a reasonable signal and it is not a guarantee. Ask how many accounts they run, in what sectors, and at what revenue share.
The more useful question: ask to see a flow they are proud of and have them explain why it is built that way. Anyone can install a welcome series from a template. Explaining the logic behind a split is harder to fake.
The flows that should exist before anything else
Welcome, browse abandonment, cart and checkout abandonment, post-purchase, and winback. These five carry the overwhelming majority of flow revenue in most stores, and plenty of accounts we audit are missing two or three of them entirely.
Beyond existence, look at the branching. A first-time buyer and a returning customer should not receive identical post-purchase emails. Someone who abandoned a £400 basket deserves different treatment to someone who abandoned a £14 one. Flat flows are where money quietly leaks.
Segmentation and deliverability
Sending everything to everyone is the fastest way to end up in the promotions tab permanently. Engagement-based segmentation, sunset flows for people who have stopped opening, and genuine suppression rules protect the asset over time.
Deliverability work should be explicit and ongoing: authentication set up properly, a dedicated sending domain, list hygiene, and someone actually watching inbox placement rather than assuming open rates tell the whole story. Ask what they do when a send underperforms. If the answer is 'test a different subject line', that is a copywriter, not a deliverability plan.
Reporting that isn't flattering nonsense
Klaviyo attributes generously by default. A wide attribution window will credit email for revenue it merely stood near, and an agency reporting that number without comment is either not looking or hoping you are not.
Good reporting shows email revenue as a share of total, flow versus campaign split, list growth net of unsubscribes, and performance against the same period last year. It should be possible to tell, from the report, whether the programme is growing or coasting.
What it should cost
UK retainers for ongoing Klaviyo management typically run from a few hundred a month for a light campaign calendar to several thousand for a full lifecycle programme with regular creative. One-off builds and audits are usually project-priced.
Whatever the number, it should be legible against the revenue the channel produces. Email is the cheapest channel most stores own, and it should be obvious from the reporting that it is paying for itself several times over.