What is a SaaS platform? Platforms vs applications vs products
When a SaaS product becomes a platform: APIs, an app marketplace and other companies building on it. A five-question test and real examples.
Part of the guide What is SaaS? A plain-English guide with examples
You are comparing two tools for your team, and one vendor calls itself a “platform” on every page while the other says “app”. You want to know whether the word means anything or is just a bigger price tag. It does mean something. A SaaS application is software you use. A SaaS platform is software you use and that other companies build on: it has public APIs, lets outside developers add features inside it and usually runs a marketplace where they sell those additions.
The difference matters when you buy, because a platform can grow with you through add-ons, and it can also tie you in more tightly. This guide gives you a five-question test, applies it to familiar products and shows the money behind one platform’s marketplace. For the basic definition of SaaS, start with What is SaaS?.
Platform in plain terms
Think of a single shop and a shopping mall. The shop sells its own goods. The mall also sells some of its own, but most of what you find there comes from other shops that rent space, follow the mall’s rules and share its customers. The mall’s value grows with every shop that moves in.
Applied to software, the everyday words line up like this:
- SaaS application (or app): a hosted product that does a job for you, used in a browser or a mobile app. A team chat tool is an application.
- SaaS product: the commercial thing you buy, with its plans and prices. Vendors use it loosely for application or platform.
- SaaS platform: an application that other companies extend. Outside developers build on its APIs, install features inside its interface and reach its customers through a marketplace.
- SaaS system: not a technical term. People use it for any hosted business software.
Most large SaaS products start as applications. They become platforms when outside developers start building on them and the vendor gives those developers rules, tools and a store.
Checklist for the platform test
Answer yes or no for any product you are evaluating. Four or five yes answers describe a platform; one or two describe an application with an API.
- Public, documented API: can any customer or developer read and write data through a documented interface, not only through the screen?
- Extensions inside the product: can outside developers add screens, buttons or workflows that appear inside the product itself?
- Marketplace: is there a store where customers find, install and pay for those extensions?
- Developer terms: does the vendor publish rules for developers, such as review, security requirements and a revenue share?
- Extensible data model: can you add your own fields, objects or record types without asking the vendor?
Classification of familiar products
The table applies the test to products whose marketplaces are public. It is a classification, not a ranking.
| Product | API | In-product extensions | Marketplace | Reading |
|---|---|---|---|---|
| Shopify | Yes | Yes | Shopify App Store | Platform |
| Salesforce | Yes | Yes | AppExchange | Platform |
| Google Workspace | Yes | Yes (add-ons) | Google Workspace Marketplace | Platform for add-ons, application for most users |
| Slack | Yes | Yes (apps in channels) | Slack Marketplace | Platform |
| A single-purpose tool with an export API | Yes | No | No | Application with an API |
Google Workspace shows why the line is fuzzy. Most users never install an add-on and see an email and documents application. For the admin who installs a dozen add-ons, it is a platform. For more on Workspace as a SaaS suite, see Google Workspace as SaaS.
Worked example: what a marketplace developer pays
A platform’s marketplace is also a business, and its terms tell you who carries the cost. Shopify publishes its developer revenue share (as of October 2026):
- 0% on the first $1,000,000 of lifetime gross app revenue, counting revenue earned on or after January 1, 2025;
- 15% on revenue above that threshold;
- a 2.9% processing fee on all billing, plus applicable sales tax;
- a one-time $19 registration fee per Partner account.
Developers who earned $20 million or more through the store in the prior calendar year, or whose company revenue reaches $100 million, pay 15% on all revenue instead.
Example: a small app developer has earned $1,500,000 of gross app revenue through the store since January 1, 2025. Sales tax is left out.
| Item | Calculation | Amount |
|---|---|---|
| Revenue share on the first $1,000,000 | 0% x $1,000,000 | $0 |
| Revenue share on the next $500,000 | 15% x $500,000 | $75,000 |
| Processing fee on all billing | 2.9% x $1,500,000 | $43,500 |
| Total paid to the platform | $75,000 + $43,500 | $118,500 |
| Kept by the developer | $1,500,000 - $118,500 | $1,381,500 (92.1%) |
Two lessons for you as a customer. First, the platform earns from products it did not build, so it has a reason to keep the marketplace healthy. Second, the extension you install is a separate company’s product, with its own pricing, support and security posture.
What the difference means when you buy
- Fit: a platform can cover gaps with add-ons instead of forcing you to switch tools. Check the marketplace for the two or three features the core product lacks.
- Cost: add-ons are billed on top. Ten extensions at $10 a month each add $100 a month to the headline price.
- Security: every extension you install gets some access to your data. Review what each one asks for, the way you would review a new vendor.
- Lock-in: the more extensions and custom fields you build up, the harder a move becomes. That is the platform working as designed.
For familiar products grouped by what they do, see SaaS examples.
Common mistakes
- Taking “platform” in the vendor’s copy at face value. The word costs nothing to print. Why it happens: it sounds bigger than “app”. Instead: run the five-question test against the vendor’s developer documentation.
- Treating a marketplace add-on as part of the core product. The add-on is usually built and supported by a different company. Why it happens: it appears inside the same screen. Instead: check who publishes it, what data it can reach and what happens if that developer stops maintaining it.
- Counting the API as proof of a platform. Many applications offer an export or reporting API and nothing more. Why it happens: “has an API” is the first line on many feature pages. Instead: look for in-product extensions and a marketplace.
- Ignoring the add-on bill. The plan price is only part of the cost on a platform. Why it happens: add-ons are priced one at a time. Instead: list the add-ons you need and add them to the per-user price before you compare vendors.
Sources
- Shopify, Revenue share for Shopify App Store developers, checked October 2026.
- Marketplaces linked in the table: Shopify App Store, Salesforce AppExchange, Google Workspace Marketplace, Slack Marketplace, each checked October 2026.
In three sentences
A SaaS application is software you use, while a SaaS platform is an application that other companies extend through public APIs, in-product extensions and a marketplace. Test any “platform” claim with five questions: API, in-product extensions, marketplace, developer terms and an extensible data model. On a platform, add-ons bring their own price, support and data access, so add them to the cost and the security review before you choose.
