🐬 Pure Swift MySQL client built on non-blocking, event-driven sockets.

What's New

4.7.1 - Add MySQL support for nested subpath (JSON) expressions

This patch was authored and released by @gwynne.

Implements SQLKit's new SQLDialect.nestedSubpathExpression(in:for:) method. #321


Documentation Team Chat MIT License Continuous Integration Swift 5.2

🐬 Non-blocking, event-driven Swift client for MySQL.

Major Releases

The table below shows a list of MySQLKit major releases alongside their compatible NIO and Swift versions.

Version NIO Swift SPM
4.0 2.0 5.2+ from: "4.0.0"
3.0 1.0 4.0+ from: "3.0.0"
2.0 N/A 3.1+ from: "2.0.0"
1.0 N/A 3.1+ from: "1.0.0"

Use the SPM string to easily include the dependency in your Package.swift file.

.package(url: "", from: ...)

Supported Platforms

MySQLKit supports the following platforms:

  • Ubuntu 16.04+
  • macOS 10.15+


MySQLKit is a MySQL client library built on SQLKit. It supports building and serializing MySQL-dialect SQL queries. MySQLKit uses MySQLNIO to connect and communicate with the database server asynchronously. AsyncKit is used to provide connection pooling.


Database connection options and credentials are specified using a MySQLConfiguration struct.

import MySQLKit

let configuration = MySQLConfiguration(
    hostname: "localhost",
    port: 3306,
    username: "vapor_username",
    password: "vapor_password",
    database: "vapor_database"

URL string based configuration is also supported.

guard let configuration = MySQLConfiguration(url: "mysql://...") else {

To connect via unix-domain sockets, use unixDomainSocketPath instead of hostname and port.

let configuration = MySQLConfiguration(
    unixDomainSocketPath: "/path/to/socket",
    username: "vapor_username",
    password: "vapor_password",
    database: "vapor_database"

Connection Pool

Once you have a MySQLConfiguration, you can use it to create a connection source and pool.

let eventLoopGroup: EventLoopGroup = ...
defer { try! eventLoopGroup.syncShutdown() }

let pools = EventLoopGroupConnectionPool(
    source: MySQLConnectionSource(configuration: configuration), 
    on: eventLoopGroup
defer { pools.shutdown() }

First create a MySQLConnectionSource using the configuration struct. This type is responsible for creating new connections to your database server as needed.

Next, use the connection source to create an EventLoopGroupConnectionPool. You will also need to pass an EventLoopGroup. For more information on creating an EventLoopGroup, visit SwiftNIO's documentation. Make sure to shutdown the connection pool before it deinitializes.

EventLoopGroupConnectionPool is a collection of pools for each event loop. When using EventLoopGroupConnectionPool directly, random event loops will be chosen as needed.

pools.withConnection { conn 
    print(conn) // MySQLConnection on randomly chosen event loop

To get a pool for a specific event loop, use pool(for:). This returns an EventLoopConnectionPool.

let eventLoop: EventLoop = ...
let pool = pools.pool(for: eventLoop)

pool.withConnection { conn
    print(conn) // MySQLConnection on eventLoop


Both EventLoopGroupConnectionPool and EventLoopConnectionPool can be used to create instances of MySQLDatabase.

let mysql = pool.database(logger: ...) // MySQLDatabase
let rows = try mysql.simpleQuery("SELECT @@version;").wait()

Visit MySQLNIO's docs for more information on using MySQLDatabase.


A MySQLDatabase can be used to create an instance of SQLDatabase.

let sql = mysql.sql() // SQLDatabase
let planets = try"*").from("planets").all().wait()

Visit SQLKit's docs for more information on using SQLDatabase.


  • Swift Tools 5.6.0
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Last updated: Wed Feb 28 2024 12:39:30 GMT-1000 (Hawaii-Aleutian Standard Time)