Implementation:SeleniumHQ Selenium FirefoxDriverLogLevel

Knowledge Sources	SeleniumHQ_Selenium Selenium Documentation
Domains	WebDriver, Firefox_Browser
Last Updated	2026-02-12 00:00 GMT

Overview

FirefoxDriverLogLevel is an enum defining the log verbosity levels supported by geckodriver, with mapping utilities to convert from Java java.util.logging.Level and JSON representations.

Description

The FirefoxDriverLogLevel enum represents the log levels recognized by geckodriver: TRACE, DEBUG, CONFIG, INFO, WARN, ERROR, and FATAL. It provides bidirectional conversion between Java's standard java.util.logging.Level values and geckodriver's log levels via a static mapping (e.g., Level.ALL/FINEST/FINER map to TRACE, Level.FINE maps to DEBUG, Level.WARNING maps to WARN, etc.). The enum also supports JSON serialization/deserialization as a {"level": "..."} map, and case-insensitive string parsing via fromString(). The toString() method returns the level name in lowercase English.

Usage

Use FirefoxDriverLogLevel to configure geckodriver logging verbosity through GeckoDriverService.Builder.withLogLevel(), or when setting the webdriver.firefox.logLevel system property. It is also used internally when serializing Firefox options to the geckodriver wire protocol.

Code Reference

Source Location

• Repository: SeleniumHQ_Selenium
• File: java/src/org/openqa/selenium/firefox/FirefoxDriverLogLevel.java

Signature

public enum FirefoxDriverLogLevel {
    TRACE,
    DEBUG,
    CONFIG,
    INFO,
    WARN,
    ERROR,
    FATAL;

    @Override
    public String toString()

    public static FirefoxDriverLogLevel fromString(String text)
    public static FirefoxDriverLogLevel fromLevel(Level level)

    Map<String, String> toJson()
    static FirefoxDriverLogLevel fromJson(Map<String, String> json)
}

Import

import org.openqa.selenium.firefox.FirefoxDriverLogLevel;

I/O Contract

Enum Constants

Constant	String Value	Mapped Java Logging Levels
TRACE	"trace"	Level.ALL, Level.FINEST, Level.FINER
DEBUG	"debug"	Level.FINE (also the default fallback)
CONFIG	"config"	Level.CONFIG
INFO	"info"	Level.INFO
WARN	"warn"	Level.WARNING
ERROR	"error"	Level.SEVERE
FATAL	"fatal"	Level.OFF

Methods

Method	Input	Output	Description
toString	none	String	Returns the lowercase English representation of the log level.
fromString	String text	FirefoxDriverLogLevel (nullable)	Case-insensitive parse; returns null if no match or input is null.
fromLevel	java.util.logging.Level	FirefoxDriverLogLevel	Converts a Java logging level to the corresponding geckodriver level; defaults to DEBUG if no direct mapping exists.
toJson	none	Map<String, String>	Returns a singleton map {"level": "<value>"} for JSON serialization.
fromJson	Map<String, String>	FirefoxDriverLogLevel	Parses a JSON map with a "level" key to the corresponding enum constant.

Usage Examples

// Configure geckodriver with DEBUG log level
GeckoDriverService service = new GeckoDriverService.Builder()
    .withLogLevel(FirefoxDriverLogLevel.DEBUG)
    .build();

WebDriver driver = new FirefoxDriver(service);

// Parse a log level from a string
FirefoxDriverLogLevel level = FirefoxDriverLogLevel.fromString("warn");
// level == FirefoxDriverLogLevel.WARN

// Convert from a Java logging level
FirefoxDriverLogLevel level = FirefoxDriverLogLevel.fromLevel(Level.WARNING);
// level == FirefoxDriverLogLevel.WARN

// Set log level via system property
System.setProperty("webdriver.firefox.logLevel", "info");
GeckoDriverService service = GeckoDriverService.createDefaultService();

Related Pages

• GeckoDriverService - Uses FirefoxDriverLogLevel in its Builder to configure geckodriver logging
• FirefoxOptions - May include log level settings in Firefox options
• FirefoxDriver - The driver whose underlying service is configured with these log levels
• FirefoxProfile - Profile settings used alongside driver service configuration