02 · The ranking, scored
Email / SMS lifecycleCRO / experimentationFull retention
#1 The Good
CROPortland, OR, US · CRO / digital experience optimization · thegood.com · Founded 2009
75/100
Rank #1 of 20 in the US
The Good: Portland-based conversion firm working exclusively on digital experience optimization for e-commerce and consumer brands since 2009. Founder Jon MacDonald has written three books on conversion and hosts the Drive & Convert podcast.
Why The Good ranks #1 in the US: The strongest results portfolio in the US list: 35+ published case studies with hard numbers (Snow Peak +149% online revenue, 16:1 average ROI claimed), plus the Drive and Convert podcast and a perfect 5.0 on Clutch. The review base itself is small (5), and the absence of lifecycle/email services caps the data-capability score.
Score composition75 of 100 pts
Results
28/30
+149% online revenue for Snow Peak16:1 avg ROI35+ case studies3 books by foundersource ↗
Specialization
17/20
Top-rated CRO firm (Clutch), Drive & Convert podcast
Data sophistication
10/20Not yet verified
Evidence found:✓structured testing+4✓attribution+2✓cross-sell / basket analysis+4No public evidence:✕segmentation / RFM✕predictive LTV✕CDP
Reputation
9/15
5/5 across 5 on Clutchawards and community footprintsource ↗
Track record
11/15
since 2009 (17 years)team ~27
#2 Invesp
CROChicago, IL, US · CRO / experimentation · invespcro.com · Founded 2006
74/100
Rank #2 of 20 in the US
Invesp: Chicago CRO pioneer founded 2006 by Khalid Saleh and Ayat Shukairy, who co-wrote the book 'Conversion Optimization'. Runs senior 7-person pods per client and its own testing tool, FigPii.
Why Invesp ranks #2 in the US: Twenty years of pure CRO practice and Clutch's #1 CRO agency worldwide five years running (2021-2025). Quantified cases like Stoneside's $1M+ added sales anchor the results score; a narrower data stack (no CDP/LTV evidence) is the main gap.
Score composition74 of 100 pts
Results
26/30
Clutch #1 CRO agency worldwide 5 consecutive yearsStoneside $1M+ added salessource ↗
Specialization
17/20
Clutch #1 CRO worldwide 2021-2025own tool FigPii
Data sophistication
10/20Not yet verified
Evidence found:✓structured testing+4✓attribution+2✓cross-sell / basket analysis+4No public evidence:✕segmentation / RFM✕predictive LTV✕CDP
Reputation
10/15
4.9/5 across 30 on Clutchawards and community footprintsource ↗
Track record
11/15
since 2006 (20 years)team ~20-50
#3 Fuel Made
Email / SMSSeattle, WA, US · Klaviyo lifecycle + Shopify CRO · fuelmade.com · Founded 2010
68/100
Rank #3 of 20 in the US
Fuel Made: Seattle agency pairing Klaviyo lifecycle marketing with Shopify CRO and design, operating since 2010. One of roughly 30 Klaviyo Master Elite partners among 6,500+ worldwide.
Why Fuel Made ranks #3 in the US: Elite-tier specialization plus a perfect 5.0 across 28 Clutch reviews. Publishes aggregate claims (email drives 20-40% of client revenue) rather than a deep library of itemized case studies, which caps the results pillar.
Score composition68 of 100 pts
Results
19/30
Email drives 20-40% of client revenueKlaviyo Master Elite (~30 of 6,500+ partners)source ↗
Specialization
20/20
Klaviyo Master Elite
Data sophistication
12/20Not yet verified
Evidence found:✓segmentation / RFM+4✓structured testing+4✓cross-sell / basket analysis+4No public evidence:✕predictive LTV✕attribution✕CDP
Reputation
9/15
5/5 across 28 on Clutchawards and community footprintsource ↗
Track record
8/15
since 2010 (16 years)team 10-49
#5 Avex
CRONew York, NY, US · Shopify Plus builds + Growth X CRO/personalization + retention · avexdesigns.com · Founded 2015
67/100
Rank #5 of 20 in the US
Avex: New York e-commerce agency founded in 2015 by John Surdakowski, pairing Shopify Plus builds with an ongoing CRO and retention practice for lifestyle brands including Kith, Hugo Boss and Equinox. Its Growth X program runs quarterly benchmarking, A/B testing and Dynamic Yield personalization, and its retention team works across Klaviyo, Attentive and Braze.
Why Avex ranks #5 in the US: The optimization evidence is real but buried: Vitality shows CVR +168% and $134K from recommendations, yet the 19-tile work page carries almost no numbers and the newest visible Clutch review dates to 2018. Publishing the Growth X numbers as named case pages and refreshing the review profile would move it up a band.
Score composition67 of 100 pts
Results
22/30
Vitality: CVR +168%, AOV +22%, $134K revenue from recommendationsKith +235% conversionsALASTIN recommendations at 13.7% of total revenuesource ↗
Specialization
17/20
Klaviyo Platinum Master (directory-verified)Shopify Plus partnerDynamic Yield Partner Excellence Award
Data sophistication
12/20Not yet verified
Evidence found:✓cross-sell / basket analysis+4✓structured testing+4✓segmentation / RFM+4No public evidence:✕predictive LTV✕attribution✕CDP
Reputation
7/15
5/5 across 12 on Clutchawards and community footprintsource ↗
Track record
9/15
since 2015 (11 years)team 10-49
#6 Rejoiner
RetentionNewport, RI, US · Email/SMS/direct-mail retention (own ESP) · rejoiner.com · Founded 2011
66/100
Rank #6 of 20 in the US
Rejoiner: Rhode Island retention shop running email, SMS and direct mail on its own proprietary ESP, combining software with a fully managed service team since 2011.
Why Rejoiner ranks #6 in the US: Rare predictive/LTV depth and solid quantified outcomes (AuthenTEAK +22% revenue; Triumph +40% YoY email revenue). Scores as a specialist rather than through Klaviyo tiers, since it runs its own platform - a structural cap on the specialization pillar.
Score composition66 of 100 pts
Results
26/30
AuthenTEAK revenue +22% to $2M+Triumph email revenue +40% YoYown platform + managed servicesource ↗
Specialization
12/20
Proprietary retention platform + managed service
Data sophistication
14/20Not yet verified
Evidence found:✓segmentation / RFM+4✓predictive LTV+4✓attribution+2✓cross-sell / basket analysis+4No public evidence:✕structured testing✕CDP
Reputation
5/15
5/5 across 14 on Clutchawards and community footprintsource ↗
Track record
9/15
since 2011 (15 years)team 10-49
#7 Luck & Co
Email / SMSSan Francisco, CA, US · Email/SMS for 7-8 figure ecommerce (Klaviyo-only) · luckandco.agency · Founded 2020
66/100
Rank #7 of 20 in the US
Luck & Co: San Francisco email and SMS agency founded by Kasey Luck that works exclusively with 7 and 8 figure ecommerce stores, entirely inside the Klaviyo ecosystem. One of Klaviyo's Elite Master partners; its Andie Swim work was published by Klaviyo as an official customer case study.
Why Luck & Co ranks #7 in the US: The Andie Swim proof is exceptional and externally validated: welcome flow CVR from 4.41% to 9.93% with an A/B test on every email, plus a Klaviyo-published 96X ROI case. The gap is volume: the case-study subdomain root 404s and the homepage results (Incrediwear +62% BFCM, +340% list growth) have no dedicated pages behind them. Five more written-up cases would make the results pillar match the tier.
Score composition66 of 100 pts
Results
25/30
Andie Swim welcome flow: CVR 4.41% to 9.93%, transactions +288%, revenue +238% YoY on flat trafficKlaviyo-published case: flow revenue +55%, 96X ROIsource ↗
Specialization
20/20
Klaviyo Elite Master (directory-verified)
Data sophistication
8/20Not yet verified
Evidence found:✓segmentation / RFM+4✓structured testing+4No public evidence:✕predictive LTV✕cross-sell / basket analysis✕attribution✕CDP
Reputation
8/15
4.6/5 across 21 on Trustpilotawards and community footprintsource ↗
Track record
5/15
since 2020 (6 years)team ~13
#8 Structured
RetentionLos Angeles, CA, US · DTC email/SMS lifecycle + paid media + CRO · structured.agency · Founded 2018
65/100
Rank #8 of 20 in the US
Structured: Los Angeles performance agency of roughly 80 people serving 100+ DTC brands, formed when Structured Social acquired Chase Dimond's email agency Boundless Labs in 2020. Runs email and SMS lifecycle programs alongside paid media and CRO for brands including Dollar Shave Club, Eight Sleep and True Classic.
Why Structured ranks #8 in the US: One of the deepest case libraries in the US category: 45 published studies including Posh Peanut at $41M+ over three years and Dr. Whitney Bowe at +168% revenue YoY. The fixable problem is the review profile: a 3.3 on Clutch where email clients rate 5.0 but paid-media clients rate as low as 0.5, so the retention practice is being dragged down by the other division's reviews.
Score composition65 of 100 pts
Results
28/30
Posh Peanut: $41M+ revenue over 3 yearsDr. Whitney Bowe: +168% revenue YoYBioTrust: flow revenue +$200KDollar Shave Club: 57% subscription CAC reductionsource ↗
Specialization
17/20
Klaviyo Platinum Master (directory-verified)45+ published case studiesChase Dimond, Partner
Data sophistication
4/20Not yet verified
Evidence found:✓segmentation / RFM+4No public evidence:✕predictive LTV✕cross-sell / basket analysis✕structured testing✕attribution✕CDP
Reputation
5/15
3.3/5 across 5 on Clutchawards and community footprintsource ↗
Track record
11/15
since 2018 (8 years)team ~80
#9 Essence of Email
Email / SMSHouston, TX, US · Email/SMS lifecycle retention · essenceofemail.com · Founded 2014
64/100
Rank #9 of 20 in the US
Essence of Email: Houston email boutique (8 people) doing full lifecycle retention: Klaviyo flows, SMS, ESP migrations and deliverability. Klaviyo Master Gold with Postscript and Stamped partnerships.
Why Essence of Email ranks #9 in the US: Publishes some of the most extreme documented outcomes in the category (Frame Destination +9,245% email revenue; Oransi $624K in under 3 months) and evidences the fullest data stack of any US email shop, including RFM and LTV modeling. Near-zero third-party reviews hold the reputation score down.
Score composition64 of 100 pts
Results
27/30
Frame Destination +9,245% email revenueOransi $624K email revenue in <3 monthssource ↗
Specialization
14/20
Klaviyo Master GoldPostscript/Stamped partners
Data sophistication
14/20✓ Verified Data-Driven
Evidence found:✓segmentation / RFM+4✓structured testing+4✓attribution+2✓predictive LTV+4No public evidence:✕cross-sell / basket analysis✕CDP
Reputation
1/15
no reviews found publiclyawards and community footprint
Track record
8/15
since 2014 (12 years)team 8
#10 Mineral.io
RetentionNew York, NY, US · Retention marketing (email, SMS, direct mail, push) · mineral.io · Founded 2016
64/100
Rank #10 of 20 in the US
Mineral.io: New York retention-only agency founded in 2016 by ecommerce operator Matt Sanocki, running email, SMS, direct mail and push programs for DTC brands including Dude Perfect, Baja Designs, L'anza and Karmaloop. Klaviyo Elite Master partner for more than six years.
Why Mineral.io ranks #10 in the US: Retention is the whole business, the Klaviyo tier is the highest available, and the published numbers are the ones merchants care about, including email revenue share by brand. The gap is proof discoverability: the case studies live only as homepage blocks, the dedicated case-study URLs 404, and there is no third-party review profile.
Score composition64 of 100 pts
Results
22/30
45% of Bellocq Tea revenue from emailDude Perfect +24% AOV and +52% Klaviyo revenue YoYKlaviyo Elite Master 6+ yearssource ↗
Specialization
20/20
Klaviyo Elite Master (6+ years)
Data sophistication
8/20Not yet verified
Evidence found:✓segmentation / RFM+4✓cross-sell / basket analysis+4No public evidence:✕predictive LTV✕structured testing✕attribution✕CDP
Reputation
5/15
no reviews found publiclyawards and community footprint
Track record
9/15
since 2016 (10 years)team ~20
#11 Flowium
Email / SMSNew York, NY, US · Email/SMS lifecycle (Klaviyo full-service) · flowium.com · Founded 2017
62/100
Rank #11 of 20 in the US
Flowium: New York full-service Klaviyo agency founded 2017 by Andriy Boychuk; runs the Email Einstein podcast and a Klaviyo training course, and sits on Klaviyo's 2026 Partner Advisory Council.
Why Flowium ranks #11 in the US: Master Elite tier, strong reviews (4.9/23) and one of the best community footprints in the list. Public case studies are lighter on hard numbers than direct peers, which limits the results score.
Score composition62 of 100 pts
Results
18/30
Klaviyo Master Elite2026 Klaviyo Partner Advisory CouncilEmail Einstein podcastsource ↗
Specialization
20/20
Klaviyo Master Elite
Data sophistication
8/20Not yet verified
Evidence found:✓segmentation / RFM+4✓structured testing+4No public evidence:✕predictive LTV✕cross-sell / basket analysis✕attribution✕CDP
Reputation
11/15
4.9/5 across 23 on Clutchawards and community footprintsource ↗
Track record
5/15
since 2017 (9 years)team 50-249
#12 Stimulate Agency
RetentionSt. Petersburg, FL, US · Full retention (email/SMS/direct mail/loyalty) · stimulate.agency · Founded 2020
60/100
Rank #12 of 20 in the US
Stimulate Agency: Florida full-retention boutique covering email, SMS, direct mail, loyalty and subscriptions, with two dedicated experts per client account.
Why Stimulate Agency ranks #12 in the US: Documented outcomes are excellent - Skinmedix email revenue from 12% to 45% of sales in 90 days, +47% LTV - and the data capability evidence (RFM, testing, attribution, LTV) is among the broadest. A young, small profile with few reviews limits reputation and track record.
Score composition60 of 100 pts
Results
24/30
Skinmedix: email revenue 12% to 45% of sales in 90 days+47% LTVsource ↗
Specialization
14/20
Klaviyo Master Gold
Data sophistication
14/20Not yet verified
Evidence found:✓segmentation / RFM+4✓structured testing+4✓attribution+2✓predictive LTV+4No public evidence:✕cross-sell / basket analysis✕CDP
Reputation
5/15
4.9/5 across 7 on Clutchawards and community footprintsource ↗
Track record
3/15
since 2020 (6 years)team boutique
#13 New Standard Co.
Email / SMSNew entryScottsdale, AZ, US · Email/SMS retention for 8-10 figure DTC brands (Klaviyo, Postscript) · newstandardco.com · Founded 2023
58/100
Rank #13 of 20 in the US
New Standard Co.: Scottsdale email and SMS retention agency founded in 2023 by Feras Khouri and Eric Rausch. New Standard Co. runs Klaviyo and Postscript programs for DTC brands including AG1, True Classic, Caraway and BYLT, and is a Klaviyo Platinum Master partner.
Why New Standard Co. ranks #13 in the US: New Standard Co. enters on results that read like a much older shop: True Classic +23% month-one repurchase and +12% LTV across cohorts, BYLT $6.1M incremental revenue in six months. The gaps are reputation and finish: no review profile on any platform, and six of its eleven case-study pages are unfinished templates without numbers of their own.
Score composition58 of 100 pts
Results
26/30
BYLT $6.1M incremental revenue in 6 monthsTrue Classic +23% month-one repurchase, +12% LTVAG1 +49% YoY Klaviyo revenuesource ↗
Specialization
17/20
Klaviyo Platinum Master (directory-verified)
Data sophistication
8/20Not yet verified
Evidence found:✓segmentation / RFM+4✓structured testing+4No public evidence:✕predictive LTV✕cross-sell / basket analysis✕attribution✕CDP
Reputation
1/15
no reviews found publiclyawards and community footprint
Track record
6/15
since 2023 (3 years)team ~16
#14 GrowthHit
CRO▼ 1Seattle, WA, US · CRO-led growth for DTC/ecommerce · growthhit.com · Founded 2016
54/100
Rank #14 of 20 in the US
GrowthHit: Seattle CRO-led growth team (40+ operators) for 7-to-8-figure DTC brands; founder Jim Huffman wrote 'The Growth Marketer's Playbook' and teaches growth for Fortune 500s.
Why GrowthHit ranks #14 in the US: Big verified aggregates ($250M+ client revenue, 1,000+ experiments) and strong reviews (4.9/20), but few itemized public case studies - aggregate claims score lower than named, numbered cases under our rules.
Score composition54 of 100 pts
Results
19/30
$250M+ client revenue across 1,000+ experiments88% of clients hit sales goalssource ↗
Specialization
6/20
Author of 'The Growth Marketer's Playbook'no platform partner tier currently verifiable
Data sophistication
10/20Not yet verified
Evidence found:✓structured testing+4✓attribution+2✓segmentation / RFM+4No public evidence:✕predictive LTV✕cross-sell / basket analysis✕CDP
Reputation
11/15
5/5 across 20 on Clutchawards and community footprintsource ↗
Track record
8/15
since 2016 (10 years)team 40+
#15 Prismfly
CRO▼ 1Miami, FL, US · CRO + Shopify + lifecycle email/SMS · prismfly.com · Founded 2020
53/100
Rank #15 of 20 in the US
Prismfly: Miami-based (distributed) agency combining CRO/experimentation with Shopify builds and lifecycle email/SMS. Klaviyo Platinum, Shopify Plus and Recharge partner.
Why Prismfly ranks #15 in the US: Impressive client outcomes (Simple Modern doubled D2C sales in a year) and a genuine multi-disciplinary stack, but founded 2020 with no public reviews yet - track record and reputation will catch up.
Score composition53 of 100 pts
Results
19/30
Simple Modern doubled D2C sales in 1 yearLuxy Hair +35% CVRsource ↗
Specialization
12/20
Klaviyo PlatinumShopify Plus, Recharge partner
Data sophistication
12/20Not yet verified
Evidence found:✓structured testing+4✓attribution+2✓CDP+2✓cross-sell / basket analysis+4No public evidence:✕segmentation / RFM✕predictive LTV
Reputation
4/15
no reviews found publiclyawards and community footprint
Track record
6/15
since 2020 (6 years)team 10-49
#16 Conversion Fanatics
CRO▼ 1Chicago, IL, US · CRO / A-B testing + PPC · conversionfanatics.com · Founded 2014
52/100
Rank #16 of 20 in the US
Conversion Fanatics: Austin CRO and A/B testing agency (founded 2014, now part of Fusion92) with thousands of tests run and a published book, 'Conversion Fanatic'.
Why Conversion Fanatics ranks #16 in the US: A 46% test win rate and standout cases like ButcherBox +40% monthly CVR, but no premium platform certifications, which caps the specialization pillar.
Score composition52 of 100 pts
Results
19/30
ButcherBox: one A/B test +40% monthly CVR46% win rate across thousands of testssource ↗
Specialization
10/20
Clutch 1000book 'Conversion Fanatic'
Data sophistication
6/20Not yet verified
Evidence found:✓structured testing+4✓attribution+2No public evidence:✕segmentation / RFM✕predictive LTV✕cross-sell / basket analysis✕CDP
Reputation
9/15
4.7/5 across 16 on Clutchawards and community footprintsource ↗
Track record
8/15
since 2014 (12 years)team ~300 (Fusion92)
#17 InboxArmy
Email / SMS▼ 1Grapevine, TX, US · Full-service email agency (50+ ESPs) · inboxarmy.com · Founded 2016
52/100
Rank #17 of 20 in the US
InboxArmy: Texas email production powerhouse: 120-150 marketers covering strategy, design, deliverability and operations across 50+ ESPs, from Klaviyo to Salesforce Marketing Cloud.
Why InboxArmy ranks #17 in the US: Scale and social proof are strong (4.9/71 on Clutch; RCJuice +400% monthly revenue from automations). ESP-agnostic generalism means no elite Klaviyo tier and thinner strategic data evidence than retention pure-plays.
Score composition52 of 100 pts
Results
19/30
RCJuice cart-abandonment automations +400% monthly revenue120-150 marketerssource ↗
Specialization
12/20
Klaviyo Silver MasterSFMC certified
Data sophistication
2/20Not yet verified
Evidence found:✓attribution+2No public evidence:✕segmentation / RFM✕predictive LTV✕cross-sell / basket analysis✕structured testing✕CDP
Reputation
9/15
4.9/5 across 71 on Clutchawards and community footprintsource ↗
Track record
10/15
since 2016 (10 years)team 120-150
#18 HiFlyer Digital
Retention▼ 1Hackensack, NJ, US · Email/SMS lifecycle retention · hiflyerdigital.com · Founded 2022
49/100
Rank #18 of 20 in the US
HiFlyer Digital: New Jersey retention shop founded by former retention VP Isaac Hyman, doing email, SMS and push for mid market DTC and retail brands and nothing else.
Why HiFlyer Digital ranks #18 in the US: Bicycle Warehouse tripling email and SMS revenue inside 90 days is a properly named result, but the headline figures the site leads with, $425M and one billion emails, belong to the founder's in house career, and no Klaviyo partner tier is listed to back the platform claim.
Score composition49 of 100 pts
Results
20/30
Bicycle Warehouse: email and SMS revenue tripled in under 90 dayssource ↗
Specialization
6/20
Self-described Klaviyo and Shopify expertsno partner tier listed
Data sophistication
12/20Not yet verified
Evidence found:✓segmentation / RFM+4✓cross-sell / basket analysis+4✓predictive LTV+4No public evidence:✕structured testing✕attribution✕CDP
Reputation
6/15
4.5/5 across 3 on Clutchawards and community footprint
Track record
5/15
since 2022 (4 years)team 6-15
#19 Growth Rock
CRO▼ 1San Jose, CA, US · Ecommerce-only CRO & A/B testing boutique · growthrock.co · Founded 2013
48/100
Rank #19 of 20 in the US
Growth Rock: Bay Area boutique doing 100% e-commerce CRO and A/B testing for 7-to-9-figure stores; publishes original UX research (mobile checkout, navigation studies) widely cited in CRO circles.
Why Growth Rock ranks #19 in the US: Rigorous, statistically honest published tests (+19% orders at 99.9% significance) and respected research, but no certifications, no third-party reviews and boutique scale - evidence quality is high, evidence volume is low.
Score composition48 of 100 pts
Results
26/30
+19% orders at 99.9% significance from free-shipping testoriginal ecommerce UX research widely cited in CRO circlessource ↗
Specialization
4/20
No formal certificationsa practice devoted entirely to e-commerce CRO
Data sophistication
10/20Not yet verified
Evidence found:✓structured testing+4✓attribution+2✓cross-sell / basket analysis+4No public evidence:✕segmentation / RFM✕predictive LTV✕CDP
Reputation
2/15
no reviews found publiclyawards and community footprint
Track record
6/15
since 2013 (13 years)team <10
#20 Retention Commerce
Email / SMS▼ 1Los Angeles, CA, US · Klaviyo lifecycle for Shopify DTC · retentioncommerce.com · Founded 2016
47/100
Rank #20 of 20 in the US
Retention Commerce: Los Angeles Klaviyo agency running lifecycle email and migrations for Shopify DTC brands, with a roster that includes MeUndies, Olive & June, Manduka, Igloo and DVF.
Why Retention Commerce ranks #20 in the US: The client roster is the entire case: not one case study, revenue figure, award or review is published anywhere, so a decade of work with recognizable DTC names sits completely unquantified.
Score composition47 of 100 pts
Results
10/30
Klaviyo directory lists Platinum Masterroster spans MeUndies, DVF, Manduka and Igloo
Specialization
17/20
Klaviyo Platinum Master (directory-verified)
Data sophistication
8/20Not yet verified
Evidence found:✓segmentation / RFM+4✓structured testing+4No public evidence:✕predictive LTV✕cross-sell / basket analysis✕attribution✕CDP
Reputation
3/15
no reviews found publiclyawards and community footprint
Track record
9/15
since 2016 (10 years)team unknown
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