Carry more CRO retainers
without buying more strategist hours.
An agency's scarce, expensive input is senior strategist time, and the work that eats the most of it (audits, research synthesis, reporting) is the work clients see the least. Spar gives those hours back: it audits each client store, builds the evidence base, ranks opportunities, writes the variation code and the weekly digest, while your strategists review and approve. You carry more clients per head, and the retainer's value shows up every week.
The binding constraint is strategist time, well ahead of test slots.
Labor is the dominant cost of running CRO, so capacity is governed by how senior hours get spent, rather than by how many experiment slots a platform offers. The most expensive part of the engagement is also the least visible to the client.
$113K to $153K
loaded cost of a single senior CRO strategist, per year
$500K+
salaries for a full in-house CRO team (developers, UX, analysts, managers)
$2K to $30K / mo
CRO retainer range, entry to premium; one-time audits run $2.5K to $4.5K
4 to 5 hrs
strategist or account-manager time per client, per month, on reporting alone
Where the hours actually go
- Audits. A full CRO audit commonly spans 6 to 8 weeks of elapsed time to gather analytics, analyze behavior, and synthesize a strategy. It front-loads the engagement with low-visibility labor and has to be repeated, largely from scratch, for every new client.
- Reporting. Agencies spend roughly 4 to 5 hours per client per month assembling reports, and DIY slide-building can run closer to 10 hours per client, a cost that scales linearly with every client you add.
Why retainers feel fragile
Retainer revenue is predictable, but only profitable if delivery hours stay bounded. Standard guidance is to cap scope at 1 to 3 tests per month precisely because a team can easily over-deliver and erase the margin. Agencies typically target 25 to 35% net and 60 to 70% delivery margin, and retainer-led shops report meaningfully higher profitability than project-led ones.
Every hour a strategist spends hand-assembling an audit or a monthly deck is an hour that erodes the margin on that retainer, or blocks the next one.
You don't scale a CRO agency by buying more test slots. You scale it by getting strategist hours out of audits and decks and back into strategy, so the same team carries more clients and the work clients renew on is visible every week.
Five places senior hours leak before a test ever ships.
Audits consume your most expensive person
A senior strategist spends days pulling GA4 funnels, watching session recordings, reading reviews, and writing findings before a single test ships. The work is elapsed over weeks, front-loads the engagement with labor the client never sees, and gets repeated from scratch for every new account.
Research is scattered across five places
Evidence is split between quantitative sources (GA4, Shopify funnels, heatmaps, recordings, prior tests) and qualitative ones (post-purchase surveys, exit surveys, support transcripts). A tool that does not connect to the rest of the stack just creates a data silo you resent within a month, and that fragmentation is multiplied by every client account.
Recommendations are inconsistent across accounts
Quality tracks whichever strategist owns the account and how much time they had that week. With no shared evidence standard, two clients with the same problem can get different-quality diagnoses, and the work that defines your brand becomes a function of who was free.
Good ideas stall waiting on design and dev
Throughput is the bottleneck, well ahead of idea supply. The majority of companies launch only 1 to 2 tests per month, roughly a third of agencies run 10 or fewer experiments a month, and about 60% manage 2 or fewer tests per person per month. The gap between a great hypothesis and a live test is where retainers underdeliver.
Client reporting is manual narrative work
Each month someone logs into multiple tools, copies numbers into a deck, and writes the story of the work, 4 to 5 hours per client and up. That cost scales linearly with client count, and when it slips the client stops seeing the value. In one survey of 125 agencies, poor reporting was the most-cited reason clients leave.
One connected loop, per client store.
Every expensive, low-visibility step gets a fast AI first draft a strategist edits. Every irreversible step (what ships, what counts as a winner, what the client sees) stays a human approval.
- 1
Connect the merchant
Your team approvesLink Shopify, GA4, Clarity, reviews, and voice-of-customer for that client into the workspace. One connection set per store, repeatable across the whole portfolio.
- 2
Build a structured evidence base
Spar draftsSpar audits the storefront and assembles the quantitative and qualitative signals into one structured evidence base, instead of leaving them spread across GA4 tabs, Clarity, review exports, and tickets.
- 3
Review and prioritize
Your team approvesSpar ranks opportunities by evidence and revenue impact; the strategist reviews and approves the ranking rather than building it from a blank page. Same prioritization logic on every account.
- 4
Draft hypotheses, tests, and fixes
Spar draftsSpar drafts the structured hypothesis and the variation code. The team edits and approves. This is what closes the gap between a great idea and a live test, with the human still the decision-maker.
- 5
Ship through the client's stack
Your team approvesDeploy via the Shopify theme app extension, create Jira items, or push into the client's existing tool (Convert, GrowthBook, Intelligems). Spar fits your workflow rather than forcing a migration.
- 6
Measure and declare winners
Your team approvesSpar runs and measures its own tests and declares winners with sequential statistics, so results are read the same consistent way across every client.
- 7
Produce client-ready output
Spar draftsSpar auto-drafts a weekly client digest, exportable as a shareable report, replacing the manual monthly deck and keeping the value of the work visible between calls.
Then the loop runs again, on its own schedule, for every store in the workspace.
See where the expensive hours go, and get them back.
The recurring monthly hours a senior strategist spends per client on audit refreshes, research synthesis, and reporting, against the same work as a Spar draft they review instead of build.
6
across 2 strategists
66 hrs
audit refresh + synthesis + reporting
~49 hrs
strategist reviews instead of builds
Mockup of the capacity view. Hours and client names are illustrative: manual figures use typical agency baselines, and the Spar column shows the review-not-build model, not measured Spar data.
What makes it agency software, well beyond an A/B testing tool.
One workspace across all client stores, with each account isolated and the whole portfolio visible. This is how you decouple consistency from any single person's available hours.
Mockup of the portfolio view. Client names and per-store status are illustrative.
Portfolio view across the book
One workspace spans every client store, so leadership sees status across the whole book of business at a glance instead of logging into each client's tooling separately.
Store-level context kept separate
Each client has its own connected data (Shopify, GA4, Clarity, reviews, voice-of-customer) and its own evidence base, so insights and variation code never bleed between accounts.
Team visibility and approvals
Hypotheses, variation code, and winner decisions move through review and approval, so a senior strategist can supervise quality across many accounts without personally producing every artifact.
Standardized intake, standardized quality
The same connect, audit, prioritize sequence runs for every new client, so onboarding thoroughness no longer depends on who happens to run it.
Reusable test knowledge
Because every client's work is structured the same way (evidence base, ranked opportunities, hypotheses, outcomes), patterns that win on one store can inform the next. This is an emergent benefit of the shared structure rather than a separate cross-client library feature.
Want the full picture of how Spar works for agencies? See Spar for agencies.
Five outcomes that show up in the P&L.
Reduce audit cycle time
A structured evidence base assembled from connected data replaces days of manual pulling and writing, compressing the front-loaded, low-visibility part of the engagement into an edit.
Increase tests per client
Closing the idea-to-build gap with drafted hypotheses, variation code, and deploy-through-your-stack lifts throughput, the metric that defines program maturity and the one most agencies are stuck on at 1 to 2 tests a month.
Standardize quality across accounts
Shared evidence and prioritization logic make the floor of work quality independent of which strategist is assigned, addressing the inconsistency that erodes client trust.
Protect strategist time
AI first drafts of audits, hypotheses, and reports give your most expensive people their hours back, the direct lever on capacity given that labor is the binding cost.
Build a more defensible retainer
A weekly, evidence-backed client digest keeps the value continuously visible. Clients leave when value is unclear rather than when results are bad, and evidence-backed work is what they renew on.
The compounding effect
If the same team carries more retainers at the same headcount, and each retainer renews longer because the value is visible weekly, both the margin and the lifetime value of the book rise together. We won't attach a multiplier to that; run it against your own retainer count, average value, and strategist cost, and the math is yours.
Jobs your strategists will recognize.
New-client audit
Connect a newly signed store and Spar returns a structured evidence base and ranked opportunities in a fraction of the usual elapsed time, so the kickoff deck is an edit rather than a from-scratch build.
Quarterly optimization roadmap
Re-run the evidence base and re-rank opportunities to produce a prioritized test roadmap for the next quarter, with the same prioritization logic across the whole portfolio.
Redesign validation
Before or after a theme or PDP redesign, ground hypotheses in the evidence base and ship A/B tests through the theme app extension or the client's tool, so the decision rests on evidence rather than opinion.
PDP conversion sprint
Target a single high-traffic product page: Spar drafts hypotheses and variation code from the evidence base, the team approves, and tests deploy quickly on the page type that most moves Shopify revenue.
Stalled-growth diagnosis
For a client whose conversion rate has plateaued, the structured evidence base surfaces where the funnel leaks across quantitative and qualitative signals in one place, replacing the scramble across tools.
Retainer reporting
Spar auto-drafts a weekly client digest, exportable as a shareable report, so the monthly deck stops being hours of manual narrative and the value of the work stays visible between calls.
Frequently asked questions
See what Spar would audit on a client store.
Point Spar at one of your client stores and get a structured evidence base and ranked opportunities back, the same first draft your strategists would otherwise spend days building. Human review stays yours on every hypothesis, line of code, and client report.