SQLDelight

SQLDelight is a Kotlin library that generates typed APIs from SQL. It suits Kotlin teams that want database changes checked before runtime; its appeal depends on the database dialects their projects need.

Overview

SQLDelight keeps SQL at the center of database access while generating Kotlin APIs around it. Compile-time checks cover schemas, statements, and migrations, which can help catch mistakes earlier in development. The trade-off is a narrow language fit: it is for Kotlin projects, not teams seeking a general-purpose generator.

The project is open source under Apache-2.0 and has no paid tiers. Its documented dialects include SQLite, MySQL, and PostgreSQL; HSQL and H2 are experimental, while CockroachDB, DB2, and Oracle dialects are third-party. That distinction matters: teams using experimental or third-party choices should verify that they meet their project’s needs.

Key features

• Compile-time database checks: SQLDelight verifies schemas, SQL statements, and migrations at compile time. That makes it a useful fit for Kotlin developers who want errors surfaced before an application runs, but it does not remove the need to choose a suitable dialect.
• SQL-to-Kotlin generation: Generated APIs give Kotlin code a typed interface to SQL statements. Projects in other languages will need a different tool.
• IDE assistance: SQL autocomplete and refactoring support, along with an IntelliJ plugin section in the documentation, can make SQL work more integrated into the Kotlin development workflow.
• Migration verification: The Gradle verifySqlDelightMigration task applies migrations to stored schema databases and checks that they reach the latest schema. This gives teams a concrete way to catch migration problems during development.
• Reactive and library integrations: Extensions cover Kotlin coroutines, RxJava, and AndroidX Paging. The coroutines extension can expose a query as a Flow and emit updated results when queried data changes, a practical option for applications that need reactive database results.
• JVM connections: The overview covers MySQL and PostgreSQL on JVM, with JDBC and R2DBC variants shown for supported dialects. Those connections add flexibility for Kotlin JVM projects, while dialect support remains the deciding constraint.

Pricing

SQLDelight: free. The open-source Kotlin SQL code generation library has no paid tiers stated, so it is a straightforward choice for individual developers and teams that want these capabilities without a software subscription. Its cost-free model does not broaden its Kotlin and dialect scope.

Platforms

SQLDelight lists Android, API, iOS, Linux, macOS, web, and Windows. It supports Kotlin; platform coverage makes it relevant across Kotlin application targets, but does not imply support for other programming languages.

Who it's for

Choose SQLDelight if your project uses Kotlin and you want SQL schemas, statements, and migrations checked during compilation, especially if its coroutines, RxJava, Paging, or Gradle integrations fit your workflow. Look elsewhere if you need generation for a different language or rely on a database whose dialect support is experimental or third-party and cannot meet your requirements.

Pros and cons

Pros

• Checks schemas, statements, and migrations at compile time, helping catch database issues before runtime.
• Open source with no paid tiers, so there is no software subscription to budget for.
• Useful Kotlin integrations, including coroutines Flow queries, RxJava, AndroidX Paging, and a Gradle plugin.
• Migration verification checks whether migrations bring stored schema databases up to the latest schema.

Cons

• Kotlin-only generation rules it out for projects built around other languages.
• Dialect support is uneven: HSQL and H2 are experimental, and CockroachDB, DB2, and Oracle are third-party choices.
• No stated security certification or compliance standard is a consideration for buyers whose requirements depend on one.

Alternatives

quicktype is another free, open-source generator; consider it instead if its API, Linux, macOS, web, or Windows platform coverage better suits your project.

Angular CLI is a free choice for projects centered on its Linux, macOS, self-hosted, or Windows platforms rather than SQL-to-Kotlin generation.

Fern may suit teams looking for a generator with a free tier for up to 10 team members, 1,000 pages, 250 AI credits per month, 2,000 page generations per month, and one site.

Hygen is a free code generator distributed through npm, Homebrew, npx, and standalone binaries; choose it if that distribution model fits better.

JHipster is a free, open-source development platform, an alternative for teams seeking a broader platform rather than a Kotlin SQL library.

Nx may fit teams seeking a free hobby tier with 50,000 monthly credits, five contributors, and 10 concurrent CI connections, rather than SQL-focused Kotlin code generation.

OpenAPI Generator is a free, open-source option for generating API clients, server stubs, documentation, and configurations.

TypeSpec is a free open-source project built by Microsoft and supported by its community; consider it if that project better matches your generation needs.

Browse more options in Code Generators or Mobile Databases.

Verdict

SQLDelight is a strong choice for Kotlin developers who want typed database APIs and compile-time checks without a paid tier. Its integrations and migration verification add practical value, but language and dialect boundaries are decisive: teams outside Kotlin, or dependent on an experimental or third-party dialect, should look elsewhere.