If you are choosing a template engine for a Java web project in 2026, it comes down to Freemarker or Thymeleaf. I built IDE plugins for both, so I have opinions and they are informed ones.
The short version: Thymeleaf is the better default for Spring Boot projects. Freemarker is more flexible when you need to render things that are not HTML. Both are mature, maintained, and production-ready. The choice depends on your project, not on which one is “better.”
Syntax
Thymeleaf uses natural templates - valid HTML with th: attributes. Your templates open in a browser without a server. That is genuinely useful for frontend collaboration. Designers can preview layouts without running Spring.
Freemarker uses its own tag syntax - ${variable}, <#if>, <#list>. The templates are not valid HTML. But the syntax is more powerful for complex logic, conditionals, and macros. If you have a template that generates email text, PDF markup, or configuration files, Freemarker handles it without pretending to be HTML.
IDE tooling
This is where I have a strong opinion, because I built it. Flexible Freemarker gives you full completion, navigation, and error highlighting in IntelliJ. It understands the Freemarker syntax inside HTML and resolves variables from your data model.
Thymeleaf has decent built-in support in IntelliJ Ultimate. The th: attributes get completion and Spring expression language resolves. It is good but not great - complex SpEL expressions still confuse the IDE sometimes.
Both are ahead of any JavaScript template engine in terms of IDE support. That is worth something.
Spring integration
Thymeleaf wins here. It is the default template engine in Spring Boot. The auto-configuration works out of the box. Spring Security integration is built in. If you are starting a new Spring Boot project today and you need server-side rendering, Thymeleaf requires less configuration.
Freemarker works with Spring Boot too - there is an official starter - but it is the second-class citizen. You will write a few extra configuration lines. Nothing dramatic, but it adds up across a team.
When to pick Freemarker
When your templates generate more than HTML. Email bodies, PDF layouts via XSL-FO, configuration files, code generation. Freemarker’s macro system is powerful and it does not care what the output format is. We used it heavily in ScipioERP for exactly this reason - the same engine rendered storefront HTML, email confirmations, and PDF invoices.
When to pick Thymeleaf
When you are building a standard Spring Boot web application and your team includes people who touch HTML but do not write Java. The natural template approach is a real advantage for collaboration. And the Spring ecosystem assumes you are using it.
What neither does well
Neither is great at reactive rendering. If your project is moving toward HTMX or Hotwire patterns, both work but neither was designed for partial page updates. You will write helper code. That is the 2026 gap in the Java template engine space, and nobody has filled it yet.