Overview
Diesel was started in 2015 and its most active maintainer today is GitHub user weiznich. Its central idea is that database interactions should be checked by the Rust compiler: diesel print-schema generates a schema.rs from your database, derives such as Queryable, Selectable and Insertable map structs to rows, and the query DSL rejects invalid column references or type mismatches before the program runs.
Migrations are plain up.sql and down.sql files managed with diesel_cli, which can also regenerate the schema after each migration. Raw SQL is supported through sql_query when the DSL does not cover a case.
Diesel 2.3, released on 12 September 2025 after 16 months of work by 95 contributors, added a HasQuery derive, window functions, SQLite in the browser via WebAssembly, JSON/JSONB for SQLite and many PostgreSQL range and array functions. The core crate is synchronous; the separate diesel-async crate provides async connections. Diesel suits teams that are willing to trade longer compile times and occasionally dense error messages for strong guarantees that queries match the schema.
Pricing and plans
| Plan | Price | What you get |
|---|---|---|
| Diesel | $0 | Dual-licensed: MIT or Apache 2.0 |
What it does
- Compile-time query checking
- Queries are type-checked against schema.rs, so missing columns and type mismatches are compile errors.
- diesel_cli
- Creates and runs up/down SQL migrations and generates schema.rs from the database.
- Derives
- Queryable, Selectable, Insertable, AsChangeset and HasQuery remove row-mapping boilerplate.
- Rich SQL DSL
- Joins, subqueries, window functions, and PostgreSQL array, JSON and range operators.
- SQLite on WASM
- Since 2.3 the SQLite backend compiles to wasm32-unknown-unknown for browser use.
Strengths and limitations
Strengths
- Strongest compile-time guarantees among Rust database crates
- Mature, with a long release history and a detailed guide
- Low runtime overhead
- Simple SQL-file migrations
Limitations
- Core API is synchronous; async needs the separate diesel-async crate
- Heavy use of generics produces long compile errors and can slow compilation
- Supports only PostgreSQL, MySQL/MariaDB and SQLite
- Minimum supported Rust version rises with releases (1.86 for 2.3)
Who it suits
Good for
- Rust backends that want queries verified at compile time
- Teams comfortable with Rust's type system
- CLI tools and apps using SQLite
Look elsewhere if
- Fully async codebases that do not want an extra crate (SQLx or SeaORM)
- Projects needing SQL Server or Oracle
Pricing history
-
Diesel 2.3 adds window functions and SQLite on WASM
Diesel 2.3 added a HasQuery derive, window functions, browser SQLite via wasm32 and SQLite JSON support; minimum Rust version is 1.86. Source ↗
Alternatives to Diesel
Questions
Is Diesel async?
The core crate is synchronous; the separate diesel-async crate provides async connections for PostgreSQL and MySQL.
How does Diesel handle migrations?
diesel_cli manages up.sql and down.sql migration files and regenerates schema.rs from the database.
Diesel vs SQLx: which should I use?
Diesel offers a typed query DSL and ORM-style derives; SQLx checks hand-written SQL at compile time against a live database and is async-first.
Sources read for this page