SQLDelight

SQLDelight generates type-safe Kotlin APIs from SQL statements, making it a strong fit for Kotlin developers who want database errors caught during compilation. Its combination of schema checks, migration verification, and IDE support suits database-focused projects, provided its dialect support matches your database.

Overview

SQLDelight treats SQL as the source for generated Kotlin APIs, rather than asking developers to build database access around loosely checked strings. It checks schemas, statements, and migrations at compile time, which can catch problems before they reach runtime. The trade-off is that its value depends on using Kotlin and a supported database dialect; it is not a general-purpose code generator for other languages.

The project is open source under Apache-2.0 and has no paid tiers. Its documentation covers SQLite, MySQL, and PostgreSQL, plus experimental HSQL/H2 dialects and third-party CockroachDB, DB2, and Oracle dialects. Experimental and third-party options merit more caution than the documented core dialects.

Key features

• Compile-time validation: Checks schemas, SQL statements, and migrations. This is useful for teams that want database mistakes surfaced during development, though it does not remove the need to choose a suitable dialect.
• Generated Kotlin APIs: Turns SQL statements into type-safe Kotlin APIs, a direct match for Kotlin applications and a poor fit for projects whose application code is in another language.
• IDE support: SQL autocomplete and refactoring support, along with an IntelliJ plugin, help keep SQL work inside the development environment.
• Migration verification: The Gradle verifySqlDelightMigration task applies migrations to stored schema databases and checks whether they reach the latest schema. That gives teams a concrete way to validate schema evolution.
• Reactive and platform integrations: Extensions cover Kotlin coroutines, RxJava, and AndroidX Paging. The coroutines extension can expose queries as Flows and emit updated results when underlying database data changes.
• JVM connections: MySQL and PostgreSQL connections are covered for the JVM, with JDBC and R2DBC variants shown for supported dialects.

Pricing

SQLDelight costs free. The free plan is the open-source Kotlin SQL code generation library, and no paid tiers are stated. That makes it accessible for individual developers and teams alike, without a paid plan to unlock the core library; there are no paid-plan seat or usage terms to weigh.

Platforms

SQLDelight is listed for Android, API, iOS, Linux, macOS, web, and Windows. Its supported language is Kotlin, so the platform breadth does not make it a fit for non-Kotlin codebases. The documented IntelliJ plugin and Gradle plugin are relevant to teams building in that ecosystem.

Who it's for

Choose SQLDelight if you build Kotlin software and want SQL-backed APIs, compile-time checks, and migration verification in the development workflow. It is particularly compelling when reactive query updates or integrations such as AndroidX Paging matter. Look elsewhere if your project needs generated code in a language other than Kotlin, or if its database depends on an experimental or third-party dialect you are not prepared to rely on.

Pros and cons

• Pro: Compile-time checks cover schemas, statements, and migrations, helping catch database issues before runtime.
• Pro: SQL autocomplete, refactoring support, and an IntelliJ plugin bring database work into the IDE.
• Pro: Coroutine Flow support can emit updated query results when database data changes.
• Pro: The Apache-2.0 project is free, with no paid tiers stated.
• Con: Generated APIs are for Kotlin, limiting its usefulness in other language ecosystems.
• Con: HSQL/H2 support is experimental, while CockroachDB, DB2, and Oracle dialects are third-party options; teams needing these databases should account for that distinction.

Alternatives

For another free, open-source generator, quicktype is an option; its listed platforms include API, Linux, macOS, web, and Windows.

Fern offers a free tier with 10 team members, 1,000 pages, 250 AI credits per month, 2,000 page generations per month, and one site, making it a separate option for readers comparing generator tools with a defined free allowance.

Hygen is a free code generator distributed through npm, Homebrew, npx, and standalone binaries. Angular CLI is another free option, with no paid plans or usage limits stated on its official pages.

JHipster is a free, open-source development platform. Nx may suit teams seeking a broader workflow with a free Hobby tier: 50,000 monthly-reset credits, five contributors, 10 concurrent CI connections, and community support.

For API-specific generation, OpenAPI Generator generates API clients, server stubs, documentation, and configurations. TypeSpec is a free, open-source, Microsoft-built, community-supported project.

Browse the Code Generators and Mobile Databases lists for more options.

Verdict

SQLDelight is an easy recommendation for Kotlin teams that want SQL to generate type-safe APIs and want schema and migration problems caught at compile time. Its free, open-source model and IDE and reactive-query support make a focused package. Choose another tool if you need non-Kotlin output, or treat the fit cautiously when your database relies on an experimental or third-party dialect.