Comparison methodology

How we substantiate the claims on our Clerk.io, Doofinder, and CartAmplify comparison pages, plus the pricing math behind the side-by-side calculator.

Every row on a comparison page links to the section here that substantiates it. Each section, in turn, points at the vendor's own public material we sourced the claim from. This is intentional: per FTC and EU comparative- advertising guidance (and our own legal preference) every claim about another vendor needs to trace back to that vendor's own published statement, not to a third-party paraphrase.

Sources

Vendor-direct sources, in order of weight:

clerk.io/pricing and help.clerk.io platform usage docs. Clerk's pricing page gates the actual numbers behind a usage calculator and a sales-contact form, but the metering rules are documented in the help-centre article above.
Doofinder Shopify App Store listing, doofinder.com, and support.doofinder.com. The Shopify ladder is the binding number for new Shopify merchants; WooCommerce / Magento / PrestaShop tend to track it.
cartamplify.com/pricing and the CartAmplify for WooCommerce plugin page.

Two third-party comparisons are referenced as supplementary context only: motive.co best-Shopify-search-app and blog.expertrec.com doofinder vs expertrec. Where vendor-direct material disagrees with a third-party comparison, the vendor-direct source wins.

All public-source URLs above were last validated 2026-Q2. We re-validate every quarter; if you spot a number on a comparison page that no longer matches the vendor's current pricing, please email [email protected] so we can re-pin the citation.

Headline numbers

Metric	Value
Doofinder Pro tier on Shopify	$186 / mo
Doofinder Advanced tier on Shopify	$436 / mo
Doofinder Basic tier on Shopify (entry)	$61 / mo
CartAmplify Starter / Growth / Amplify	$49 / $149 / $399 / mo
Clerk.io published entry tier	Calculator-quoted (no public floor)
Seekmodo Hobby (entry) / Starter / Growth / Scale	$29 / $99 / $299 / $999 / mo
Public Model Context Protocol (MCP) server	Seekmodo: Yes. Clerk.io, Doofinder, CartAmplify: No.
Vendors serving Zen Cart, MediaWiki, Discourse, or Drupal natively	Seekmodo: Yes. Clerk.io, Doofinder, CartAmplify: No.

Pricing ladder comparison

Vendor	Entry price	Top published	Pricing basis
Clerk.io	Calculator-quoted (no public floor)	Calculator-quoted	Per successful API call: each search submission, each instant-search result-type rendered (0.2 usage per type per keystroke), each recommendation impression, each email send, audience-size events.
Doofinder	$61 / mo (Basic, Shopify)	$436 / mo (Advanced) + custom	Per request, including admin navigation, every shopper keystroke, every AI Assistant turn, and every indexing operation.
CartAmplify	$49 / mo (Starter)	$399 / mo (Amplify)	Hybrid product-count + per-API-request metering with a 50,000-product hard cap on the top published tier.
Seekmodo	$29 / mo (Hobby)	$999 / mo (Scale) + custom	Search volume — 5K → 5M post-bot-check shopper search submissions per month.

Three caveats worth pulling out of the table:

Clerk.io's public floor isn't published. The pricing page is a calculator that gates the actual numbers behind a quote-request flow. Clerk's usage docs describe the metering rules but not the per-tier prices. The three-month auto-upgrade rule, however, is published — exceed your tier for three consecutive months and your subscription moves up the ladder per their Terms of Service §F.
Doofinder's $61 / $186 / $436 ladder is the Shopify App Store listing. The marketing site historically advertised lower entry pricing, but the live Shopify listing is the binding number for new Shopify merchants.
CartAmplify's product cap matters. Even Amplify ($399 / mo) caps at 50K SKUs — anything larger requires a custom plan that isn't publicly priced. Mid-market Magento / BigCommerce catalogs routinely exceed this; the published ladder is structurally for small-to-mid Shopify and WooCommerce stores only.

Search-volume pricing vs per-keystroke pricing — the worked example

Seekmodo prices on post-bot-check search submissions. Doofinder prices on raw API requests, which include every keystroke that paints a result, every admin navigation, and every indexer write. The two pricing bases produce dramatically different bills for the same shopper traffic.

Worked example: a Shopify store with 5,000 monthly shopper search submissions.

Assume an average shopper types 5 characters before they stop typing or pick a result. Each typed character that paints results in Doofinder's instant-search counts as a request. Plus index updates (real-time update on save, daily feed reprocessing). Plus admin navigation. A reasonable monthly request total is:

Source	Count
Search submissions	5,000
Instant-search keystrokes (5,000 × 5)	25,000
AI Assistant turns (10% of submissions × 3 turns each)	1,500
Real-time indexing on update	8,000
Admin / stats-page navigation	1,000
Total Doofinder requests	~40,500

This blows past the Doofinder Basic ($61 / mo) request quota and lands the merchant on Pro at $186 / mo just to keep the lights on, or pushes them into overage on Basic. On Seekmodo Starter ($99 / mo, 100K searches), the same traffic uses 5,000 of 100,000 quota — 5% of the allowance — and bot-check pre-filters the bots from even those 5,000.

The math for typical Shopify traffic is roughly: Seekmodo Starter ($99 / mo) ≈ Doofinder Pro ($186 / mo) at like-for-like coverage, with 95% of quota headroom remaining and the bot load excluded.

The Clerk.io equivalent is harder to model precisely because the floor is calculator-quoted, but the structural comparison holds: Clerk counts 0.2 usage per result-type displayed on every keystroke. Same shopper, same shape of bill.

Want to plug your own numbers in? The pricing calculator runs this same arithmetic against your monthly search volume.

Open-source CMS depth — vendor-vacuum positioning

The open-source CMS lanes (Zen Cart, MediaWiki, Discourse, Drupal, Joomla, Ghost) have near-zero commercial AI-search vendor density. None of Clerk.io, Doofinder, or CartAmplify serves any of these. Even Clerk's 12-platform reach (Shopify, WooCommerce, Magento, BigCommerce, PrestaShop, Shopware, Lightspeed, DanDomain, Smartweb, Shoporama, JTL, DynamicWeb) does not include a single open-source CMS.

Seekmodo's shipping connector lineup includes WordPress (with WooCommerce), Zen Cart, Magento, BigCommerce, and MediaWiki, with Discourse, Drupal, and PrestaShop on the published roadmap. The open-source CMS reach is structurally part of the product, not a roadmap aspiration.

For a tenant that runs a Zen Cart store, a WordPress blog, and a MediaWiki knowledge base on the same domain, Seekmodo's commerce, content, and knowledge verticals run all three on a single tenant + plan. None of the three comparison vendors offers an equivalent.

How we keep this honest

Every vendor-claim row links to the vendor's own public material — pricing page, app-store listing, help article, or feature page. If a vendor changes a number, our claim stops resolving and the row is flagged for re-validation in the next quarterly review.
Each /vs/ page includes a "When [vendor] is the better fit" section. That's an EU Directive 2006/114/EC Article 4(d) — and UK CAP 3.32 — compliance shape: comparative advertising must acknowledge legitimate competitor strengths, not just leverage their weaknesses.
The trademark footers on every comparison page identify the vendor with text only (no logos), per nominative-fair-use convention.
Words that would breach Article 4(g) of the same directive (no presenting your goods as imitations or replicas) — "imitation", "replica", "knock-off", "clone of", "rip-off" — are prohibited in our comparison copy and a unit test enforces it.

Have a vendor you'd like to see compared, or a row you think we've mis-substantiated? Email [email protected]. Comparative-advertising compliance is a quarterly review for us; the dataset gets healthier the more eyes are on it.