Kimai: Open-Source Time Tracking Software for Freelancers and Teams

What is Kimai?

Kimai is a free open-source time-tracking application designed for freelancers, agencies, and businesses that bill by the hour. Built on modern Symfony PHP framework, Kimai enables teams to track time spent on projects, manage rates, generate invoices, and analyze productivity. Over 50,000 users worldwide use Kimai to accurately track billable hours and improve project profitability.

Unlike Harvest ($9-99/month per user) or Toggl Track ($99-199/month), Kimai provides time tracking without per-user licensing costs. Organizations deploy Kimai on-premises or in the cloud, maintaining complete data ownership while enabling teams to track and bill accurately.

Kimai serves as the central hub for time tracking, invoicing, and project profitability analysis. Freelancers track billable hours and generate invoices for clients. Agencies allocate team members across projects and monitor profitability. Managers identify over/under budget projects and adjust resource allocation.

Key Features and Capabilities

Time Tracking

Start/Stop Timer: One-click timer for active time tracking with visual countdown
Manual Entry: Log past time entries with date, start time, and duration
Batch Entry: Quickly enter multiple time entries in bulk
Activity Management: Track activities (meetings, coding, admin) separately
Tags: Tag time entries for categorization and filtering
Descriptions: Add detailed descriptions of work performed
Time Rounding: Automatic rounding to nearest 5 or 15 minute interval

Project and Client Management

Unlimited Projects: Track unlimited projects for multiple clients
Client Profiles: Store client information, rates, and billing details
Budget Tracking: Set project budgets and monitor spending against budget
Project Rates: Define different hourly rates per project, client, or activity
Team Assignment: Assign team members to projects and monitor allocation
Categories: Organize projects into logical categories

Invoicing and Billing

Invoice Generation: Automatically generate invoices from tracked time entries
Invoice Templates: Customizable invoice templates with branding
Payment Tracking: Mark invoices as paid, pending, or expired
Expense Tracking: Track project-related expenses and add to invoices
Multi-Currency: Support for multiple currencies and exchange rates
Tax Handling: Configure tax rates and automatic tax calculation
PDF Export: Export invoices as PDF for email or filing

Reporting and Analytics

Time Reports: Analyze time spent by project, client, activity, or employee
Revenue Reports: Track billable revenue and analyze profitability
Expense Reports: Monitor project-related expenses and costs
Export Data: Export reports as Excel, PDF, or CSV
Time Summary: View aggregated time summaries by various dimensions
Custom Reports: Create custom reports with specific metrics and filters

System Requirements and Technical Specifications

Server Requirements

Operating System: Linux (Ubuntu 18.04+, Debian 9+, CentOS 7+) or Windows Server
Web Server: Apache 2.4+ with mod_rewrite or Nginx 1.14+
PHP: 7.4+ with required extensions (curl, gd, json, mbstring, mysql, openssl, session, xml, zip)
Database: MySQL 5.7+ or MariaDB 10.3+ for data persistence
RAM: 512MB minimum for testing, 2GB+ recommended for production
Storage: 2GB+ initial allocation for application and data
CPU: Single-core minimum, dual-core recommended
PHP Memory Limit: 128MB minimum, 256MB recommended

Client Requirements

Modern web browser: Chrome 60+, Firefox 55+, Safari 11+, Edge 79+
JavaScript enabled for timer and interactive features
Minimum 1024×768 resolution
Optional: iOS 10+ or Android 5+ for mobile time tracking

Installation and Deployment

Docker Installation

# Run Kimai with Docker
docker run -d 
  --name kimai 
  -p 8080:80 
  -e ADMINMAIL=admin@example.com 
  -e ADMINPASS=admin 
  -e DATABASE_URL=mysql://user:password@mysql:3306/kimai 
  kimai/kimai:latest

# Access at http://localhost:8080

Linux Manual Installation

# Install dependencies
sudo apt-get install git php7.4 php7.4-mysql php7.4-curl php7.4-gd composer

# Clone Kimai
git clone https://github.com/kevinpapst/kimai2.git
cd kimai2

# Install PHP dependencies
composer install

# Configure database
# Create .env file with DATABASE_URL

# Run installation
php bin/console kimai:install

# Start web server
php -S 127.0.0.1:8000 -t public/

# Access at http://localhost:8000

Production Configuration

# Configure Apache or Nginx as reverse proxy
# Enable mod_rewrite for clean URLs

# Set up automated database backups
# Configure SSL/HTTPS with Let's Encrypt

# Monitor application logs and performance

Use Cases and Real-World Applications

Freelancers and Solo Practitioners

Individual freelancers use Kimai to track time on client projects, accurately bill clients, and analyze profitability. Hourly invoicing ensures clients are billed correctly for work performed. Time reports show productivity metrics and identify high-margin projects.

Service Agencies

Agencies use Kimai to track team member time across multiple client projects. Project managers monitor time against budgets to identify over-budget projects early. Profitability analysis reveals which clients and projects generate the best margins.

Consulting Firms

Consultants bill by the hour and use Kimai to accurately track time. Multiple hourly rates per consultant and client ensure correct invoicing. Time reports support project costing and resource planning for future engagements.

Software Development Teams

Development teams use Kimai to track time on features and bugs. Project managers monitor time to identify scope creep and adjust timelines. Time tracking supports accurate project estimation for future development work.

Advantages of Kimai

Simple to Use: Intuitive time tracking interface with one-click timer start/stop
Invoicing Integrated: Generate professional invoices directly from tracked time
Cost Effective: Free self-hosted versus $9-99/month per user for Harvest or Toggl
Multi-User: Unlimited team members without per-seat fees
Customizable: Full source code allows custom modifications for specific workflows
Detailed Reports: Comprehensive reports for project analysis and profitability
Data Ownership: All time and billing data remains on your infrastructure
Mobile Apps: Native iOS and Android apps for time tracking on the go
API Access: Programmatic access for integration with other business systems

Limitations and Considerations

UI Design: Interface simpler than modern SaaS time tracking applications
Setup Complexity: Initial configuration requires technical setup
Mobile Experience: Mobile app not as feature-rich as web interface
Community Support: Support relies on community rather than paid support SLAs
Infrastructure Management: Self-hosted deployments require server maintenance