Best for
Best for Amazon sellers and agencies whose main workload is advertising, with research and listing checks alongside.
E-commerce Seller Tools Comparison
SellerApp vs. What Sells Next
At a glance
At a glance
Best for
Best for Etsy sellers who make their own products and want to test an idea against the market before making it.
- Freelancers
Cataleo does not name a winner. Both statements come from the vendors themselves.
Full Comparison
| Criterion | SellerApp | What Sells Next |
|---|---|---|
| Starting price | Freemium free; Pro from $99 / month The pricing FAQ states a yearly plan saves 50% against monthly billing; yearly amounts are not shown. Smart is $149 a month for the first 3 months, then $250. | Free Premium is £12 per month, tax included, cancel anytime. |
| Free trial | Freemium plan with limited access, no credit card required | No trial; an ongoing free plan instead |
| API | Paid Amazon data APIs for products, keywords, listing quality, FBA fees and profit, with a key issued on subscribing and 100 free tokens to start | Not stated |
| Hosting | Cloud: a web app and a browser extension | Cloud: a web app and a Chrome extension |
| Made in | Not stated | United Kingdom |
| Product research | Product research and product intelligence, ASIN tracking of historical pricing, sales estimates, revenue trends and listing quality over time, and a browser extension that shows data on Amazon product pages | Product discovery, Opportunity Radar and the Crossover Lab, which combines a product with a theme. Idea checks show comparable Etsy listings, asking prices and buyer signals, with an idea board and build guides for planning the make. |
| Marketplace keyword research | Keyword Explorer for keyword research and a keyword tracker that monitors rankings; keyword tracking is part of the Pro plan | Keyword research and Keyword Smash |
| Listing optimisation | Listing Quality Index (LQI) analysis of Amazon listings across 6 to 7 areas; listing optimisation and creation is also sold as a managed service per parent ASIN | Listing audit, AI listing drafts with editable titles, descriptions and 13 tags, AI copy reviews of connected listings, saved listing drafts, concept visuals and listing videos from product photos |
| Competitor tracking | Competitor research, and ASIN tracking that follows any product's pricing, sales estimates and listing quality over time | Competition watch with estimated sales and revenue, search visibility for connected shops, and a weekly market briefing |
| Fee and profit calculation | Profit and loss tracking at every level of the account, plus FBA Fees and Amazon Profit Calculator APIs | Fee and profit calculator |
| Marketplaces covered | Amazon; the pricing page lists US, CA, MX, BR, DE, ES, FR, IT, NL, PL, SE, TR, UK, SA, AE, AU, IN, JP and SG, while its FAQ names 15 of these | Etsy |
| Integrations and API | Paid APIs for product details, best sellers by category, category tree, reviews, keywords, keyword tracking, indexing, listing quality, FBA fees, profit, storefronts and search results; pricing is usage-based and on request | An optional read-only Etsy shop connection, with changes copied into Etsy by hand, and a Chrome extension |
| AI features | Yes | Yes |
| Deployment | Cloud (SaaS), Browser-based | Cloud (SaaS), Browser-based |
| Support | Email helpdesk, Chat | Not stated |
| Onboarding | Personal consulting | Not stated |
| Company size | Not stated | Freelancers |
| Integrations | Browser extension | more entries Etsy, Chrome extension |
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Row where the values differ The small markers point at the lower number, the longer list or the stated feature. They describe the data, they are not a verdict.
The short version
Key Differences
- Starting price SellerApp Freemium free; Pro from $99 / month What Sells Next Free
- Free trial SellerApp Freemium plan with limited access, no credit card required What Sells Next No trial; an ongoing free plan instead
- Hosting SellerApp Cloud: a web app and a browser extension What Sells Next Cloud: a web app and a Chrome extension
- Product research SellerApp Product research and product intelligence, ASIN tracking of historical pricing, sales estimates, revenue trends and listing quality over time, and a browser extension that shows data on Amazon product pages What Sells Next Product discovery, Opportunity Radar and the Crossover Lab, which combines a product with a theme. Idea checks show comparable Etsy listings, asking prices and buyer signals, with an idea board and build guides for planning the make.
- Marketplace keyword research SellerApp Keyword Explorer for keyword research and a keyword tracker that monitors rankings; keyword tracking is part of the Pro plan What Sells Next Keyword research and Keyword Smash
Every line is one datapoint from the table above, picked automatically. Nothing here is written text.
The trade-offs
Strengths and Limitations
SellerApp
Strengths
- Freemium plan with no credit card required
- Advertising automation and research in the same account
- Listing Quality Index analysis of Amazon listings
- Documented Amazon data APIs, starting with 100 free tokens
Limitations
- Yearly prices are not shown, only a stated 50% saving
- Smart is discounted only for the first 3 months, then $250 a month
- API pricing is on request
- Agencies pay 0.5% to 2.5% of Amazon ad spend on top of the base fee
What Sells Next
Strengths
- Free plan with daily keyword lookups and idea checks, no card needed
- Idea checks show comparable Etsy listings, asking prices and buyer signals
- Fee and profit calculator and build guides sit next to the research
- The Etsy shop connection is optional and read-only
Limitations
- The site names Etsy as the only marketplace
- Listing changes have to be copied into Etsy by hand
- Competitor sales and revenue are estimates
- The site does not state the company or country behind the tool
Plans
Pricing
SellerApp
- Freemium $0 For sellers getting started on Amazon. Basic functionalities including product research; no credit card required.
- Pro From $99 / month Adds insights and tracking, keyword tracking, listing quality and email support.
- Smart From $250 / month $149 a month for the first 3 months. Adds ads automation, a quarterly business review, email and chat support, a dedicated account manager and custom development.
- Custom On request Smart plan plus data warehousing, custom development, a product solution expert and priority support.
- Agency $300 plus 0.5% to 2.5% of Amazon ad spend Agency program with ad automation, multiple accounts and reporting; the FAQ calls $300 a starting sum and states no minimum duration.
What Sells Next
- Free £0 5 keyword lookups per day, 3 starter crossovers and 5 idea checks per rolling 24 hours. No card needed.
- Premium £12 Per month, tax included, cancel anytime. Introductory offer: the first month is £5.
What users say
Review Scores · opens after launch
SellerApp
- Ease of use
- Not rated yet
- User interface
- Not rated yet
- Onboarding
- Not rated yet
- Support and service
- Not rated yet
- Value for money
- Not rated yet
- Features
- Not rated yet
No reviews yet. Nothing has been published here yet, and no score is shown. How a review is checked before it appears is described below.
What Sells Next
- Ease of use
- Not rated yet
- User interface
- Not rated yet
- Onboarding
- Not rated yet
- Support and service
- Not rated yet
- Value for money
- Not rated yet
- Features
- Not rated yet
No reviews yet. Nothing has been published here yet, and no score is shown. How a review is checked before it appears is described below.
How we check reviews
Before sending, the author has to confirm three things: that they have used the product themselves, that they work neither for the vendor nor for a competitor, and that nobody is paying them for the review. We also ask whether the vendor invited them to write it. That answer is required, either answer is accepted, and it stays with the review.
Every review is read by a person before it appears. An email address is required and is confirmed: we send a link to it, and a review does not reach us until the author opens that link, so a review has a sender who was reachable at least once rather than being anonymous. Where what somebody writes needs backing, we ask them for evidence that they used the product, and a review that does not get it is not published. We publish positive and negative reviews alike, we pay nothing and offer nothing for a review, and we accept none that was bought or incentivised.
What we cannot do is verify a purchase. There is no shop here and no account, so whether the author really used the tool rests on their own declaration, on whatever we ask them for, and on the plausibility of what they write. We say so rather than implying a check that does not exist.
A vendor cannot buy a review, and cannot have one removed or changed because they dislike it. We remove or edit a review only if it breaks our rules or the law, for example a false statement of fact. Paid placement has no effect on which reviews appear or on any score.
Where this comes from
Where this comes from
SellerApp https://www.sellerapp.com/ · checked against the official source on 2026-11-11
What Sells Next https://whatsellsnext.com/ · checked against the official source on 2026-11-10
This table lists factual criteria taken from information the vendors publish themselves. For how we put it together, see the methodology.