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Chronos Agency vs Flowium

Both Chronos and Flowium are Klaviyo Elite Master agencies built for ecommerce. Both focus on email and SMS. Both have been operating since 2017. If you're evaluating the two, you're already looking in the right category.

This page breaks down how the two agencies compare across the dimensions that actually matter when you're choosing a retention partner: team depth, engagement model, Klaviyo expertise, case studies, and what it's actually like to work with each agency day to day.

We're Chronos, so we're not a neutral party here. But we've kept this factual. Everything about Flowium on this page comes from their public website, FAQ page, Clutch profile, and Klaviyo partner directory listing.

Side-by-side overview

How both agencies approach ecommerce retention

Chronos and Flowium share a similar starting point: email and SMS are the highest-margin channels for ecommerce brands, and most programs are underperforming. Both agencies lead with Klaviyo expertise and both structure engagements around strategy, execution, and optimization.

Where the two diverge is in depth of strategic involvement. Chronos operates as an LTV partner, building retention systems designed to maximize customer lifetime value across the full lifecycle, not just send more emails. The strategy extends beyond channel execution into segmentation architecture, purchase cycle analysis, and long-term revenue optimization. Flowium's positioning centers on email marketing execution with defined plan structures and monthly deliverable counts.

Team depth and how resources are allocated

Chronos operates with 85+ full-time specialists across a portfolio of roughly 60 active brands at any given time. That ratio is intentional and it's the thing most Chronos clients mention first when asked what sets the agency apart. It means significantly more people than clients. Each brand works with a named six-person team: strategist, campaign manager, email copywriter, email designer, QC team, and data analyst. The strategist typically manages one to two accounts.

This is also why Chronos caps its active portfolio. When capacity is full, new brands go on a waitlist until the team grows. The agency limits its own scale to preserve that ratio.

Flowium operates with approximately 60 employees and assigns a six-person team per client: senior account manager, account manager, copywriter, designer, tech specialist, and assistant. They do not publicly disclose how many active clients they manage at any given time, so the team-to-client ratio is not directly comparable.

Klaviyo expertise and partner tier

Both Chronos and Flowium hold Klaviyo Elite Master status, the highest tier in Klaviyo's Service Partner program. The tier hierarchy runs from Silver Master at the entry level, through Gold Master and Platinum Master, up to Elite Master at the top.

Elite Master status reflects the volume of accounts an agency manages, the revenue generated through the platform, and the depth of technical certification across the team. Agencies at this tier receive priority support from Klaviyo's product and engineering teams, early access to beta features, and dedicated technical resources.

Since both agencies hold the same tier, the Klaviyo credential alone does not separate them. The difference shows up in how each agency applies that expertise at the account level.

How each agency works with clients

This is where the two agencies differ most.

Phased sprint into ongoing retainer

Chronos structures every engagement in two phases. The first is a scoped sprint tailored to whatever the brand needs fixed first. For some brands, that means a BFCM preparation sprint. For others, it means a foundational retention build: rebuilding core flows, deploying lead capture, and setting up the data infrastructure for ongoing optimization. The sprint is scoped to the brand's specific gaps, identified during a detailed audit. It is not a generic onboarding template.

The second phase is an ongoing retainer. Each brand gets a dedicated team of six specialists (strategist, campaign manager, email copywriter, email designer, QC team, and data analyst) who stay with the account. Communication runs through a dedicated Slack channel with a 4-hour response window. Clients receive weekly written progress updates, monthly (or as-needed) strategy and alignment calls, a custom data dashboard tracking key metrics, and a built-in A/B testing cadence. There are no long-term contracts.

Strategy drives the output; meaning that email count depends on a brand's need and requirements. The team adapts based on what the data shows each cycle, adjusting volume and focus as the brand's needs evolve. Clients describe the result as having a team that "responds nearly instantly," that is "very knowledgeable, segments, and does A/B testing without my direction," and that "delivers good results without me having to think much about email marketing.

The longest Chronos client relationships span 5-6 years. Multiple clients describe results that compounded over time: one brand went from 5% email revenue to 15% to 41%. Another went from 3% to 15%+. Another from 8% to 20%. These are not sprint outcomes. They are what happens when the same team stays on the account and keeps optimizing.

Plan tiers based on monthly email volume

Flowium structures engagements around plan tiers defined by monthly email volume. Their most popular options are the Gold plan (25 emails per month) and Silver plan (15 emails per month). Each plan includes a dedicated six-person team, strategy, creative, campaign execution, A/B testing, and reporting. Emails beyond the plan's monthly allocation can be purchased at an additional per-email rate. SMS is available as a separate monthly add-on.

Flowium offers month-to-month contracts with a 60-day cancellation period, plus discounts for longer commitments: 10% off for a 6-month agreement and 20% off for 12 months. They also offer a 2-year price lock guarantee, meaning the rate will not increase for two years after signing. Onboarding includes a kickoff and branding call, followed by a customized strategy, calendar, and templates.

They also offer a one-time Foundational Flow Setup project (7 flows with 20 emails) for brands that want flow infrastructure without an ongoing retainer.

Neither agency publishes specific dollar amounts publicly.

What the difference means for prospects

If you're evaluating both, the core question is whether you want a fixed-output model (a set number of emails per month with clear deliverables) or a strategy-driven model (where the output adapts to your brand's needs and the team operates as an extension of your marketing department). Both structures work. The right one depends on how you want the day-to-day relationship to function and whether you value predictable output or adaptive strategy.

What clients say about working with Chronos

Video testimonials

Services and channel coverage

Chronos covers six channels: email, SMS, push notifications, WhatsApp marketing, RCS, and direct mail. The agency positions itself as an LTV-focused lifecycle marketing partner, meaning the strategy layer sits above any individual channel. Services span the full retention lifecycle: lead capture optimization, welcome flows, cart and browse abandonment, post-purchase journeys, cross-sell and upsell, win-back, sunset flows, deliverability management, segmentation, A/B testing, campaign execution, and reporting.

Chronos supports a wide range of email and SMS platforms: Klaviyo, Attentive, Yotpo, Postscript, Omnisend, HubSpot, ActiveCampaign, Braze, Mailchimp, Dotdigital, and Brevo. Most clients are on Klaviyo, but migrations from other platforms are a regular part of the work.

Flowium covers seven channels: email, SMS, push notifications, WhatsApp, RCS messaging, Instagram DM automation, and direct mail. Their service list includes email strategy, automation, campaign management, design, copywriting, Klaviyo migration, deliverability audits, and segmentation. Their FAQ names Klaviyo, HubSpot, Salesforce Marketing Cloud, Mailchimp, and Customer.io as supported ESPs, with experience across additional platforms.

Both agencies share six of the same channels. Flowium's additional channel (Instagram DM automation) may be relevant for brands looking to automate messaging on that platform. Chronos supports a wider range of named ESPs, which matters if a brand runs on a platform outside the Klaviyo ecosystem or is considering a migration.

Case studies and results

The Oodie

Lifecycle-led retention for a 9-figure brand. 30%+ email revenue share. Cart recovery conversions went from 4% to 12%. Unsubscribe rates dropped 57%.

9-figure brand

Fenix

Owned-channel revenue scaled from 23% to 71%.

23% to 71% owned revenue

TheraICE

153% increase in customer retention.

153% retention increase

Ecotraveller

Email revenue share scaled from ~12% to ~40% in under 60 days.

12% to 40% in <60 days

Truly Beauty

8x increase in monthly email performance. 223x growth in email and SMS revenue in 12 months. A six-year client relationship.

6-year partnership

Organifi

46.3% of revenue attributed to email and SMS. 234x increase in email revenue in 6 months.

234x email revenue growth

Calming Blankets

67% higher email revenue. 120% list growth. Email share up from 27% to 47%.

27% to 47% email share

Sommer Ray Shops

65% email revenue boost.

65% revenue boost

Flowium publishes case studies featuring True Classic, RSVLTS, Lulalu, The Sports Edit, Wine Awesomeness, and pH-D Feminine Health.

Both agencies have served hundreds of ecommerce brands. Flowium has served roughly twice as many, which naturally produces a higher cumulative total. The per-brand depth of engagement, the duration of client relationships, and the scale of individual outcomes are where the two agencies differ most. Chronos's longest partnerships span 5-6 years, demonstrating sustained performance across growth stages.

Third-party reviews, awards, and recognition

Chronos Agency awards and recognition

• Clutch Global Award + Clutch Champion, Fall 2025 (top 15 per category globally)
• Clutch 1000, 2025 (top 1% of all companies on the platform)
• Clutch Global Winner + Clutch Champion, 2023
• Clutch Global Leader, 2020 (one of 15 email marketing agencies recognized out of 300)
• Clutch 1000, 2019 (top 1% globally, earned two years after founding)
• Klaviyo Elite Master Partner

Flowium awards and recognition

• Inc. 5000 Honoree, 2025
• Klaviyo Elite Master Partner

One theme that appears in some of Flowium's reviews (both Clutch and Glassdoor) is occasional turnover of account representatives, with several reviewers noting transitions between team members during their engagement. If continuity of your account team is important to you, this is worth asking about during evaluation.

Content and thought leadership

Flowium invests heavily in SEO content marketing. They publish "Best Klaviyo Agencies" and "Best Email Marketing Agencies" listicles where they rank themselves first using a proprietary "Rating by Flowium" scoring system. They also publish individual competitor review articles and Klaviyo-vs-competitor ESP comparisons. Their blog is extensive and clearly built for organic traffic.

Chronos's content footprint includes a podcast featuring DTC founders and ecommerce operators, webinars, guides, ebooks, and a design gallery showcasing client email creatives. Founder Joshua Chin is a regular speaker at major ecommerce conferences including Affiliate World Conferences, Smart Marketer's Blue Ribbon Mastermind, Smart Marketer Live, Adworld, Geekout (multiple seasons), and ShopX. Joshua also co-founded Ecom North, Canada's first ecommerce conference.

If you're evaluating agencies based on content you've found through search, it's worth knowing that many "best agency" listicles are self-published by the agencies they rank. Flowium's listicles use Flowium's own rating criteria. This is common in the space but important context.

Where each agency stands out

Who is each agency best for?

Frequently asked questions