Only one of the fifteen landing page and conversion agencies we read on 20 October 2026 shows a named client's conversion rate before and after the work: Apexure, whose IMD Business School page went from 3.91% to 6.38% on two hypotheses. Every other lift we found is a percentage with no starting point, so a reader cannot tell a page that went from 2% to 3% from one that went from 20% to 30%.
We read each agency's own landing page or conversion service page, or its homepage where no service page exists, and recorded seven things. The table, the lift claims and the questions they raise are below. We build landing pages ourselves and appear in the table under the same checks, last and unranked.
How we picked and read the fifteen
We started from the agencies named in public "best landing page agency" lists and in search results for landing page design and landing page optimisation, then kept those with a reachable English website on 20 October 2026. The set mixes three kinds of firm a buyer will meet under the same search: landing page studios, paid-media agencies that build their own pages, and conversion rate optimisation (CRO) firms that test pages others build.
For each, we read one page: the landing page service page where it exists, the homepage otherwise. Every figure below is the agency's own, vendor-sourced claim about its own work; we did not check any of them with the clients. We did not contact anyone or follow case-study links, so a figure that lives only inside a case study does not count. The service page is what a buyer reads first, and where an agency chooses which evidence to lead with.
The seven checks: whether landing pages are named as a service; whether any price is published, and whether it is the agency's own; whether a test count or a rule for calling tests is given; whether a result is tied to a named client; whether the starting rate is shown; which builder is named; and whether any build or test duration is stated.
The seven checks, side by side
| Agency | Landing pages named | Price published | Test count or rule | Named-client lift | Baseline | Platform | Timeline |
|---|---|---|---|---|---|---|---|
| Apexure | Yes | No, quote in 48 hours | Sample size fixed in advance | Yes, three clients | Yes, IMD | Unbounce, Webflow, Framer, WordPress, more | First variant within the first month |
| Aimers | Yes | Market range in FAQ | No | Leads only | No | Webflow, WordPress, HubSpot, Wix | Several weeks |
| Conversion | No, "conversion centred design" | No | No | Yes, revenue and donation size | No | Own tool only | Positive ROI within 12 weeks |
| Conversion Rate Experts | No, "webpages" | No | No count | No | No | No | No |
| Conversion Sciences | Yes | Market ranges in FAQ | 35,000+ or 20,000+; significance | Yes, two clients | No | No | One test runs 2 to 8 weeks |
| ConversionLab | Yes | Fixed price, no figure | 33 tests for one client; 95% | Yes, two clients | No | HubSpot setup | One page in 5 business days |
| Flowout | Yes, under development | From $5,900 a month | No | No | No | Webflow only | Case durations only |
| Hey Digital | Yes | No | No | Yes, ads and pages together | No | Ad platforms only | 30 to 90 day rollout |
| KlientBoost | Yes, as a guide | No | No | No | No | Unbounce, in a guide | No |
| Konstruct Digital | Yes | No | Tests where traffic allows | No | No | No | A few weeks per page |
| Linear | Yes | No | No | Leads only | No | Unbounce, Instapage | No |
| SaaS Hero | Yes | Not on the homepage | No | Person named, company not | No | Figma for drafts | 3 to 4 weeks to live |
| Speero | No | No, budget bands on form | Yes, two clients | No | No | Testing tools only | No |
| SplitBase | Yes | No | No | Yes, one client | No | Shopify Plus partner | Revenue rise within 90 days |
| Superside | Yes | No | No | No | No | Webflow | 98% on or ahead of schedule |
| Octo Agency (us) | Yes | No, quoted per project | None published | None published | No | Webflow, Next.js | Four-week marketing-site process |
Source: each agency's own website, self-reported, read 20 October 2026
Every named-client lift we found, and what came with it
A lift is only as useful as what sits next to it: the starting rate, the tests behind it and what was measured. This is every client-attributed result on the fifteen pages.
| Agency | Client | Result claimed | Baseline | Tests or duration | What it measures |
|---|---|---|---|---|---|
| Apexure | IMD Business School | +63% conversions | 3.91% to 6.38% | Two hypotheses, dated October 2024 | Brochure downloads |
| Apexure | Flare | +65% demo requests | No | No | Demo requests |
| Apexure | DOOR3 | 76% lower cost per lead | $2,300 to $550 | No | Cost per lead |
| ConversionLab | Campaign Monitor | +1,187% cumulative; +260% in six months | No | 33 tests, 10 pages | Conversion rate |
| ConversionLab | BetterWorld | +116% | No | No | Not stated |
| Conversion Sciences | American Express GBT | +78% conversions | No | No | B2B lead-gen landing pages |
| Conversion Sciences | Rhino Fleet Tracking | +61% conversions | No | No | Quote form completion |
| SplitBase | Laura Geller | 43% conversion rate increase | No | No | Conversion rate |
| Hey Digital | PostHog | 18.5% more cloud conversions, 17.05% lower CPA | No | No | Ads and pages combined |
| Conversion | Unicef | Average one-off donation up more than 50% | No | No | Donation size |
| Conversion | Clarks | £2.8 million | No | First experiment | Revenue |
| Linear | Premier Liposuction | Leads up 30% to 40% | No | Three months | Leads, in a testimonial |
| Aimers | CrowdSync Technology | 20% to 30% more qualified leads | No | No | Leads from paid search, in a testimonial |
Source: agency websites listed below, self-reported, read 20 October 2026
Three things stand out. First, Apexure's IMD row is the only one a reader can recompute: 6.38 divided by 3.91 is a 63% relative lift, which matches the headline. Second, ConversionLab gives the most test detail, 33 tests across 10 pages and an average of 36% per test, but 33 times 36% is about 1,188%, which suggests the 1,187% cumulative figure is the sum of individual test lifts rather than a measured before-and-after rate. The 260% in the first six months, quoted in the client's own testimonial, is the more useful number. Third, several rows measure leads, revenue or donation size rather than page conversion. They may be real and still say little about page design.
What the pages say about the market
Prices are rare, and two of the three figures are not price lists. Flowout publishes monthly plans, from $5,900 for web design to $9,900 for development with design and copywriting. Conversion Sciences and Aimers quote ranges in their FAQs framed as what agencies typically charge (see the FAQ below). Linear says it has "transparent landing page design prices" and shows none.
Test counts and test rules rarely appear together. ConversionLab is the only agency that both counts tests and states a significance rule. Conversion Sciences gives two different totals on the same page, 35,000+ tests since 2007 in the statistics strip and more than 20,000 in its differentiators section, and two different aggregate claims: 300+ websites with a 15% lift or higher in one place, 300+ with a sitewide lift of 25% or more in another.
Unattributed numbers fill the gaps. Superside shows a 30%+ conversion lift after optimisation with no client. Linear says its AI targeting averages 30% more conversions. KlientBoost says it hit 83% of client goals in Q2 2026. SplitBase says every CRO client onboarded in 2023 to 2025 saw revenue rise within 90 days, and SaaS Hero that clients generally see 3x SQL growth in 90 days. None can be checked from the page.
The firms with the most testing detail sell programmes, not pages. Speero, Conversion and Conversion Rate Experts describe experimentation programmes and do not name landing pages. Speero's evidence is test velocity: MongoDB from zero to 100 tests a year in six months, Freshworks from zero to ten tests a month. That is the right evidence for a CRO programme and the wrong evidence for a one-page build.
The fifteen in brief
Apexure. UK hours, 3,000+ pages built and tested since 2015 for over 300 clients, a sample size fixed before each test and losing tests reported. It says one client's readout waited for 300 to 400 visitors per variant, an honest sign of how small landing page samples are.
Aimers. SaaS paid media with a landing page service and post-launch testing. Its results are testimonials about leads; two case-study headlines (210% and 55%) carry no client name on the page.
Conversion. Over 100 CRO specialists in the UK and North America, its own experiment repository, Liftmap, and named outcomes for Unicef, Wistia and Clarks.
Conversion Rate Experts. Lists Amazon, Apple, Google, Facebook and Dropbox as clients and a Wins Database of 19 years of tests. No figures, prices or timelines.
Conversion Sciences. On-shore US staff, two named B2B results and an ROI guarantee ("if we don't deliver results, you don't pay"). The two test totals need reconciling.
ConversionLab. A Trondheim studio: one landing page in five business days at a fixed price, then a testing retainer. The Campaign Monitor case is the most detailed of the fifteen.
Flowout. A Webflow Enterprise Partner in Maribor and Wilmington with published pricing and 490+ projects shipped; no lift figures. We build in Webflow too, so read this row knowing we compete with it.
Hey Digital. B2B SaaS paid media. Its PostHog and Toggl results mix ad and page work, so the page's share is unknown.
KlientBoost. Its landing page URL is a guide hub headed "The Ultimate Guide To Landing Pages That Convert In 2022", claiming thousands of pages built. No named client.
Konstruct Digital. B2B and industrial focus, a clear process from intent mapping to CRM tracking, and no landing page results shown.
Linear. Utah, 400+ team members, pages on Unbounce and Instapage, testimonials about leads rather than conversion rates.
SaaS Hero. B2B SaaS paid media with in-house landing pages, drafts in Figma and month-to-month terms.
Speero. Austin, Tallinn and London; the clearest testing-velocity evidence in the set, and not a landing page studio.
SplitBase. Ecommerce CRO and landing pages, a Shopify Plus partner, many named brands and one clean named-client figure.
Superside. Webflow landing pages from a modular component library. Named clients appear for design capacity, not page performance.
Octo Agency. Where we sit on the same checks: we build marketing sites and landing pages in Webflow and applications in Next.js, quote per project, and run a four-week process for a marketing site. Named clients include Web Tonic, for whom we have built more than twenty Webflow sites in twelve months as a white-label partner, and USLege, a legal-tech redesign. We publish no test count and no lift figure yet, which puts us in the same column as most of this list.
What this means for choosing a landing page agency
Decide first whether you are buying a page or a testing programme. A page needs a studio that names its platform, its timeline and who builds it; a programme needs traffic, a test rule and a firm that reports losses. Then ask every shortlisted agency for one result with a baseline, a visitor count per variant and a duration, and treat a refusal as information. If you are comparing Webflow partners in particular, our earlier piece, 17 White Label Web Development Partners Checked on Their Own Sites, applies the same method to build partners. Our landing page service page explains how we scope one.
