Best Retention &
CRO Agencies 2026
Affinsy's opinionated ranking of retention, email/SMS lifecycle and CRO agencies for e-commerce brands across the US, UK and DACH. We researched the field ourselves and scored what can be publicly verified, with a deliberate bias: demonstrated data work, not marketing claims. Rank position is never purchasable.
51 agencies · Researched by the Affinsy team · Updated August 11, 2026
How agencies are scored
Every agency is scored 0-100 across five pillars from publicly verifiable evidence collected in August 2026. Evidence is weighted by tier: independently verified beats self-published, self-published beats claimed. The weighting is ours and deliberately favors data-driven operators; we publish the full rubric so you can disagree with it.
The Data Sophistication pillar is scored from public claims until verified. Earning the ✓ Verified Data-Driven badge means showing the data work behind the listing: a case study or work example we validate by hand, or one free Affinsy analysis on a client store. It is never granted for a reply alone.
Separately, any agency can confirm its listing: check what we published and tell us what is wrong. Corrections ship with the next edition, they are free, and they change nothing about the score. Confirmed listings say so under the card, which tells you the facts came from the agency rather than only from our research.
Proven results
Quantified case studies: email revenue share, LTV, CVR, repeat rate. Volume and standout bonuses on top of an evidence base score.
Specialization
Klaviyo partner tier (Elite > Master Platinum > Master Gold > Platinum > Partner) or CRO-platform credentials. Self-claimed expertise scores low.
Data sophistication
Segmentation / RFM, predictive LTV, cross-sell / basket analysis, structured testing, attribution, CDP. Scored from each agency's public claims until verified with real evidence.
Reputation
Third-party review volume and rating, industry awards, community footprint.
Track record
Years operating and client volume in e-commerce retention or CRO.
Excluded during sourcing: platform and tool vendors (Ebbo, ELAINE, Salesfire), absorbed agencies (Electriq), experimentation firms without an e-commerce-primary practice (Conversion.com, Cro Metrics, Speero, Daydot, Creative CX), generalists (WAUMEDIA, e-dialog), and agencies whose claims could not be verified (REO).
Questions about the ranking
- Which retention and CRO agencies rank first in each market?
- In the United States, The Good ranks #1 with 75 of 100. In the United Kingdom, Underground Ecom ranks #1 with 80 of 100. In the DACH region (Germany, Austria, Switzerland), konversionsKRAFT ranks #1 with 67 of 100. All scores are from Affinsy's August 2026 edition.
- Which markets does the Affinsy agency ranking cover?
- The ranking covers the United States, the United Kingdom and the DACH region (Germany, Austria, Switzerland), with 51 agencies scored in total across the three markets in the August 2026 edition.
- How does Affinsy score retention and CRO agencies?
- Each agency is scored 0-100 across five pillars: proven results (30 points), specialization (20), data sophistication (20), reputation (15) and track record (15), from publicly verifiable evidence collected in August 2026. The weighting deliberately favors demonstrated data work over marketing claims.
- Can an agency pay to be listed or to rank higher?
- No. Rank position is never purchasable and no agency pays to appear in the ranking. Verification is free and changes nothing about the score.
Earn the Verified Data-Driven badge
Show the data work behind your listing: run a free analysis on one client store, or submit equivalent evidence. The badge lands in the next monthly edition.
Verification is free · Rank position is never purchasable