Open-Source Databases · kotlin-orm

ktorm

Ktorm is a lightweight Kotlin ORM framework built on pure JDBC that provides type-safe SQL DSL and sequence-style APIs for database operations. It requires no configuration files, XML, or annotations, and generates SQL automatically while maintaining strong compile-time type checking.

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Source: GitHub — github.com/kotlin-orm/ktorm

2.3k

GitHub stars

162

Forks

Kotlin

Primary language

Apache-2.0

License (OSI-approved)

Key facts

Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.

Field	Value
Repository	kotlin-orm/ktorm
Owner	kotlin-orm
Primary language	Kotlin
License	Apache-2.0 — OSI-approved
Stars	2.3k
Forks	162
Open issues	104
Latest release	v4.2.1 (2026-06-20)
Last updated	2026-06-20
Source	https://github.com/kotlin-orm/ktorm

What ktorm is

Ktorm offers dual interfaces: a strong-typed SQL DSL for fine-grained SQL control and entity sequence APIs mirroring Kotlin collections. It uses JDBC directly, supports flexible dynamic queries, entity binding via interface definitions, and is extensible for custom operators, data types, and database dialects.

Quickstart

Get the ktorm source

Clone the repository and explore it locally.

terminalbash

1git clone https://github.com/kotlin-orm/ktorm.git2cd ktorm3# follow the project's README for install & configuration

Need it deployed, integrated, or customized instead? DEV.co ships production installs.

Best use cases

Kotlin-native backend services requiring type-safe database access

Teams building JVM applications in Kotlin who want compile-time safety and IDE autocomplete for database queries without runtime reflection or annotations.

Projects needing fine-grained SQL control with type safety

Applications where generated SQL must be optimized or non-standard, and developers need visibility and control over queries while maintaining type correctness.

Lightweight microservices and API backends

Small to medium services where ORM overhead matters and minimal dependencies are a priority; Ktorm adds no third-party dependencies beyond Kotlin stdlib.

Implementation considerations

Define table objects as Kotlin objects mapping database columns; optionally bind to entity interfaces for sequence API support.
Database connection is explicit (Database.connect); manage connection lifecycle and pooling (e.g., HikariCP) according to deployment topology.
SQL generation is deterministic and inspectable; debug generated SQL early and test with actual target database dialect.
No automatic schema management or migrations; use external tools (Flyway, Liquibase) or manual DDL for database schema changes.
Entity objects are interfaces, not data classes; property access is dynamic; be mindful of N+1 query patterns when navigating relationships.

When to avoid it — and what to weigh

Java-only projects or non-JVM languages — Ktorm is Kotlin-exclusive; Java projects would require wrapper layers or should use alternative JVM ORMs like Hibernate or jOOQ.
Teams unfamiliar with Kotlin or preferring ORM convention over control — If your team lacks Kotlin expertise or prefers heavy ORM automation (automatic migrations, lazy loading proxies, etc.), the learning curve and philosophy may not align.
Complex domain models with deep inheritance hierarchies — Ktorm's entity binding is interface-based and straightforward; projects with elaborate inheritance patterns or polymorphic queries may require significant custom work.
Rapid prototyping requiring zero database setup — While Ktorm is lightweight, you still define schema in code; projects needing auto-generated schemas from annotations may prefer JPA-style ORMs.

License & commercial use

Apache License 2.0 permits commercial use, modification, and distribution. License text available in repository. Standard OSI-approved permissive license with no patent claims.

Apache 2.0 is a well-established permissive OSI license clearly permitting commercial use without royalties or proprietary restrictions. No commercial support vendor or SLA model is described in provided data; review vendor support offerings independently if needed.

DEV.co evaluation signals

Editorial assessment — not user reviews. Directional, with an explicit confidence level.

Signal	Assessment
Maintenance	Active
Documentation	Adequate
License clarity	Clear
Deployment complexity	Low
DEV.co fit	Good
Assessment confidence	High

Security considerations

Ktorm uses parameterized queries (prepared statements with ?) reducing SQL injection risk for DSL-generated code. JDBC connection credentials are passed directly to Database.connect(); secure credential management (environment variables, secrets vaults) is caller's responsibility. No input sanitization, encryption, or audit logging mentioned; implement at application or database layer.

Alternatives to consider

Hibernate / JPA

Mature, Java-standard with Java/Kotlin support, but heavier, annotation-driven, and less control over generated SQL. Better for large schema-first projects.

jOOQ

Comparable Java/Kotlin DSL strength and SQL control, widely adopted, but commercial licensing and larger footprint. Best if strict JPA compatibility is required.

Exposed (JetBrains)

Kotlin-native alternative by JetBrains; similar DSL philosophy but includes DAO/entity layer. Consider if deep IDE/framework integration with IntelliJ ecosystem is priority.

Software development agency

Build on ktorm with DEV.co software developers

Evaluate Ktorm for type-safe, dependency-free ORM in Kotlin services. Contact Devco to assess fit for your architecture and database requirements.

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ktorm FAQ

Does Ktorm support async/non-blocking database operations?

Not stated in provided data. Ktorm is JDBC-based, which is blocking by default. Review documentation or source for coroutine/reactive wrapper support.

Can I use Ktorm with Spring Boot or Quarkus?

Not explicitly documented in excerpt, but Ktorm's minimal dependencies and explicit configuration suggest compatibility. Confirm via ktorm.org docs or community examples.

How is performance compared to raw JDBC or other ORMs?

No benchmarks provided in data. Ktorm claims to be lightweight and efficient; independent benchmarking against target workload is recommended.

Is database migration/schema versioning built in?

No. Ktorm does not include migration tools; use Flyway, Liquibase, or manual DDL alongside Ktorm for schema management.

Software developers & web developers for hire

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Is Ktorm Right for Your Kotlin Backend?

Evaluate Ktorm for type-safe, dependency-free ORM in Kotlin services. Contact Devco to assess fit for your architecture and database requirements.

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