Scaladoc

Scaladoc is Scala’s source-comment documentation generator, built for library authors and developers who need API references that reflect code structure. It is a strong fit for Scala projects; teams with complex builds will find sbt the more practical generation route.

Overview

Scaladoc turns comments into structured HTML references, so library users can navigate documentation alongside the code’s types and relationships. It accepts Scala source code, TASTy files and JAR files, making it useful for publishing API documentation from more than one form of Scala input. It is not a general-purpose documentation system for unrelated languages or APIs.

The output can include package breadcrumbs, linear supertypes, known subclasses and type hierarchies, as well as links to online source when available. Those structural cues help readers understand where a symbol sits in a library, rather than leaving them with a flat collection of descriptions.

Key features

Comments support Markdown in Scala 3 and legacy Wikidoc syntax. Tags such as @param, @tparam, @return, @throws, @example, @since and @deprecated give authors a way to document individual code entities consistently. Scaladoc can also inherit comments from superclasses and traits, implicitly or through @inheritdoc, which can reduce repeated explanations in class hierarchies.

API documentation can be generated with sbt or the scaladoc command-line tool. The direct command is harder to use for projects with multiple source files and library dependencies, so sbt is the better fit for complex builds. Scaladoc can also produce static sites for documentation and blog posts alongside API references, extending its role beyond symbol-level documentation.

Search can locate methods and fields by type, a useful capability when a reader knows the shape of a value but not its name. That search feature is still in development, so it should not be treated as a finished centerpiece of the documentation workflow.

Pricing

Scaladoc is open source and free: its plan costs nothing. There is no free trial because the tool is already free, and no paid plan or usage cap is stated. That makes it straightforward for individual contributors and teams to adopt without per-seat or quota trade-offs.

Platforms

Scaladoc is listed for Linux, macOS, Windows and web. Its generated documentation is HTML, while the documentation workflow centers on Scala code and the Scala ecosystem.

Who it's for

Scaladoc suits Scala library authors who want comments close to source, developers responsible for generating library documentation, and library users who need a structured API reference. It is less suitable as a language-agnostic publishing tool or where a project needs a mature type-based search experience as a core requirement.

Pros and cons

• Pros: Scala-aware references can expose type hierarchies, supertypes, subclasses and source links, which helps readers navigate complex APIs.
• Pros: Comment tags, supported markup and inherited documentation provide several ways to keep explanations tied to code entities.
• Pros: Free, open-source use avoids paid tiers and stated usage limits.
• Cons: The command-line route becomes harder with multiple source files and dependencies; complex projects are better served by sbt.
• Cons: Type-based search is still in development, limiting confidence in it as a mature discovery feature.

Alternatives

For broader documentation-generation needs, browse Documentation Generators. Choose Asciidoctor when you need an open-source documentation processor with core converters for HTML 5, DocBook 5 and man pages; PDF support is also mentioned. JSON Schema for Humans is a better fit for generating static HTML or Markdown documentation from JSON Schema.

Kotlin/JS is the relevant alternative when the goal is compiling Kotlin for JavaScript rather than documenting Scala APIs. Scalar fits API documentation workflows that need an editor and SDK tooling, with its free plan capped at three APIs, one SDK of up to 25 endpoints, one editor seat and 50 Agent Scalar credits. Sphinx is another open-source documentation option that can be installed locally or self-hosted.

Swagger Codegen is the better choice when documentation needs to be generated from OpenAPI specifications alongside API clients and server stubs. Swift Package Manager is a free open-source package management tool, while DocFX is an open-source static site generator that requires .NET SDK 8.0 or higher.

Verdict

Choose Scaladoc if you publish Scala libraries and want API documentation grounded in source comments, with navigable type structure and no stated usage caps. Look elsewhere if you need a general-purpose generator, or if complex builds make a direct command-line workflow undesirable and sbt is not part of your setup.