The best ecommerce conversion rate optimization services match your actual bottleneck, show a documented testing method, and price their work against the revenue you can realistically gain. Nostra AI suits stores that lose sales to slow pages, bot traffic and checkout bugs. SplitBase and Invesp suit brands that want a dedicated testing team. Conversion and Conversion Rate Experts fit larger experimentation programs. Conversion Sciences suits teams that want a guarantee, and Spiralyze suits teams that want speed on a flat fee.
Most store owners start this search with a vague goal, "more conversions," and a long list of agencies that all promise the same thing. That makes comparison hard, and a wrong pick can cost months of retainer fees. Conversion rate is simple math, orders divided by sessions, so a provider can raise it by improving the store, by cleaning up the traffic you measure, or by testing better messaging.
This article sorts seven providers by what they do, who they fit and how they charge. Nostra AI publishes this blog, so it appears first, and it is an infrastructure fix, not a testing agency. We describe the other six from what they publish about themselves. A guide to costs and selection follows the list.
Nostra AI is a platform of five AI agents that run at the edge of your storefront and fix the technical problems that quietly cut conversion: slow pages, bot traffic, lost tracking and checkout bugs. It does not run A/B tests or redesign pages. It improves the conditions your tests and ad traffic depend on, and it deploys with a DNS-level change and no code changes.
A faster, cleaner, better-measured store converts more before you test a single headline.
Each agent owns one conversion leak, and the platform runs across more than 300 ecommerce brands. Here is what each agent does:
This service suits mid-size and large Shopify and Salesforce Commerce Cloud brands that have no spare engineering time. Customers include Nixon and Credo Beauty. Setup starts on day one with the DNS connection, the agents then observe your store for days 2 to 14, and automated optimization continues after that. The platform is SOC 2 compliant.
Pricing for the full platform comes from the Nostra team. Knox, the bot agent, comes with a 14-day free trial and a month-to-month contract you can cancel anytime. Pair Nostra with a testing agency from this list if you also want experiments and redesigns.
SplitBase is a conversion and landing page agency built for 8- and 9-figure direct-to-consumer ecommerce brands. It fits when paid traffic is scaling and you want a full team on your conversion rate, not a single freelancer. Its focus is narrow, and that is its main selling point.
SplitBase is a specialist's pick: a DTC-only focus, priced for brands past $10M in revenue.
SplitBase's method, called the 3Ps (Patterns, Perception, Proof), starts with quantitative and qualitative research before any A/B testing or landing page work begins. Each engagement includes:
SplitBase suits DTC brands above roughly $10M in annual revenue that want testing tied to ad spend. Its full-service programs start at $8,500 per month, according to published pricing. A smaller store, or one that sells mostly wholesale, may not get full value from a team built around DTC paid traffic.
Invesp is a dedicated CRO agency that pairs a structured testing framework with a no-lift, no-fee option. That option means fees depend on verified conversion improvements. It works with small, mid-size and enterprise stores.
Invesp's pitch is aligned incentives: if conversion does not move, the fee should not either.
Invesp runs every engagement through its SHIP framework:
The agency reports more than 900 clients and over 36,000 A/B tests. It can build variations in the testing tool you already use, such as VWO, Optimizely or Convert.
Invesp suits teams that want a documented process they can inspect before signing. Retainers start at about $9,000 per month, and the performance-based structure ties fees to results. Before you sign, ask how a lift is measured, over what baseline and over what period. Those terms decide whether the guarantee has teeth.
Conversion is an experimentation agency, in business since 2008, with a team of more than 100 people. It sells high-velocity testing programs that run many experiments in parallel. That model works best when you have the traffic to support it.
Conversion is built for volume: many tests, run continuously, guided by a library of past results.
The agency's work rests on three proprietary assets:
It also offers a personalization service. Named clients include Canon, Whirlpool and the Motley Fool.
Conversion suits brands with enough traffic to run several tests at once and leadership that treats experimentation as an ongoing program. Low-traffic stores will struggle to reach reliable results at this pace. Ask for a quote scoped to testing volume, and ask which parts of the toolkit your program would actually use.
Conversion Sciences is a fully managed CRO agency founded in 2007 by Brian Massey. Its Conversion Catalyst program bundles research, design, development and testing for a monthly fee with weekly status updates. It also advertises a results guarantee.
A guarantee is only as good as its definition, so read the terms before you read the case studies.
Conversion Catalyst gives you a complete conversion team for one price. The agency says its hypotheses draw on more than 20,000 tests across over 150 clients. Other points to know:
It suits teams that want a fully managed program and a provider that accepts accountability for the outcome. Pricing is custom. Ask three questions about the guarantee: which metric it covers, what baseline it uses, and what the remedy is if the target is missed. A promise to keep testing is not the same as a refund.
Conversion Rate Experts is a research-first agency known for its nine-step CRE Methodology. It is a two-time winner of the Queen's Award for Enterprise, and its client list includes Amazon, Dropbox and Booking.com. It leans toward stores with real traffic and a real budget for discovery work.
Conversion Rate Experts front-loads the thinking: you pay for understanding before you pay for tests.
The methodology starts well before the first experiment:
Reviewers recommend it for ecommerce and for high-traffic environments, where its structured experimentation and deep research pay off. It suits larger stores with complex funnels and several traffic sources. Request a quote, and ask how long the research phase runs before the first live test, because that delay decides when you see returns.
Spiralyze is a fully managed CRO agency that uses a proprietary prediction engine to choose which tests to run. It sells on speed and a flat fee, and it works with both ecommerce brands and B2B SaaS companies.
Spiralyze trades a long research phase for pattern-matching on thousands of past tests, and charges accordingly.
The engine draws on A/B test data scraped from 78,000 websites to predict which changes will win on your site. The agency says it handles design, copy, development, QA, analytics and project management. Its fees include testing tools such as VWO, Hotjar and CrazyEgg. A test-to-live cycle takes one to two weeks, and it reports first wins within 43 days.
Spiralyze suits teams that want fast tests and no long-term contract. The flat fee is $25,000 per month with no contract commitment, the highest published figure in this list. Performance-based and pilot pricing are available on request. It advertises a guaranteed 30% lift, so check how that is defined. At this price, your store needs enough revenue for a lift to cover the fee.
Choose by bottleneck first, then by engagement model, then by price. A store with slow pages and polluted analytics needs different help than a store with healthy traffic and weak product pages.
Fix what you measure, then fix what you test.
Ecommerce conversion rate optimization services usually combine research (analytics review, heatmaps, surveys), A/B testing of pages and checkout steps, landing page work and reporting. SEO brings visitors to the store, and CRO raises the share of those visitors who buy. Neither replaces the other.
A technical layer sits beneath both. Bot traffic inflates sessions, which pushes your reported conversion rate down for no real reason. Slow pages and checkout bugs leak sales before a test can help. That is why Nostra AI sits first on the list.
Published starting prices run from about $8,500 to $25,000 per month. Several providers quote on request.
| Provider | Model | Starting price reported |
|---|---|---|
| Nostra AI | Edge agents, DNS-level setup | Knox: 14-day free trial, month-to-month |
| SplitBase | Dedicated DTC team | From $8,500 per month |
| Invesp | Retainer or no-lift, no-fee | About $9,000 per month |
| Conversion | Experimentation program | Ask for a quote |
| Conversion Sciences | Managed program with guarantee | Custom pricing |
| Conversion Rate Experts | Research-led methodology | Ask for a quote |
| Spiralyze | Flat fee, no contract | $25,000 per month |
Here is a worked example. A store with 100,000 sessions a month, a 2% conversion rate and an $80 average order value earns $160,000 a month. A 10% relative lift to 2.2% adds 200 orders, or $16,000 a month. An $8,500 retainer would absorb more than half of that gain. At 500,000 sessions, the same lift adds $80,000 a month. The same $160,000 store would see a 3% revenue lift, the figure Nostra expects from Dash, add $4,800 a month.
Put these to every provider on your shortlist:
The right ecommerce CRO service depends on where your store leaks. Slow pages, bot-inflated sessions, short-lived tracking and checkout bugs call for an edge-level fix like Nostra AI. Weak messaging and untested pages call for a testing agency such as SplitBase, Invesp, Conversion, Conversion Sciences, Conversion Rate Experts or Spiralyze. Many stores need both, in that order.
Run the numbers before you compare proposals, and ask each provider for its method in writing. If bot traffic is inflating your sessions and wasting ad spend, see how Edge Protect filters bad bots before they reach your store.
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