The best open source alternative to Bigcapital is Akaunting. If that doesn't suit you, we've compiled a ranked list of other open source Bigcapital alternatives to help you find a suitable replacement. Other interesting open source alternatives to Bigcapital are: Crater and Frappe Books.
Bigcapital alternatives are mainly Accounting Software but may also be Invoicing & Payment Tools or Expense Management Tools. Browse these if you want a narrower list of alternatives or looking for a specific functionality of Bigcapital.
Self-hostable accounting software covering invoicing, expense tracking, cash flow, and client portals. Free to use, available in 50+ languages.

Akaunting is a free, web-based accounting platform built for small businesses and freelancers who need real bookkeeping tools without a subscription fee. It runs in the browser, so your financials are accessible from any device. The self-hosted Standard plan costs nothing and gives you full access to the source code.
The core workflow covers the essentials most small operations actually need:
For freelancers juggling multiple clients, the client portal alone saves a lot of back-and-forth. Compared to tools like Invoice Ninja or Frappe Books, Akaunting leans toward a hosted-first experience with a clean UI that doesn't assume accounting knowledge.
The software supports 50+ languages, contributed by volunteers worldwide, which makes it practical for businesses outside English-speaking markets. It's used in over 100 countries. If you've been paying for something like Xero or QuickBooks just to send invoices and track expenses, Akaunting covers that ground without the monthly bill.
Looking for open source alternatives to other popular services? Check out other posts in the alternatives series and openalternative.co, a directory of open source software with filters for tags and alternatives for easy browsing and discovery.
Crater offers AI-driven invoicing workflows, payments, and working capital tools to enhance your platform with minimal technical effort.

Crater: Revolutionizing Financial Operations with AI
Crater is an innovative AI-powered embedded AR/AP automation solution designed to transform how platforms handle financial operations. With minimal technical lift, you can integrate powerful tools that streamline invoicing, payments, and working capital management.
Key Features:
Intuitive Invoicing Workflows: Simplify the process of paying and getting paid with user-friendly interfaces.
Seamless Payment Integration: Offer ACH and card acceptance with simplified onboarding for your users.
Working Capital Tools: Solve cash flow challenges with advanced AR/AP features, including 'Buy Now, Pay Later' options.
Accounting Automation: Enable effortless data integration between your platform and popular accounting software.
AI-Powered Financial Copilot: Get instant answers to financial questions, create invoices, and generate reports with ease.
Benefits for Your Platform:
Crater's AI-driven approach ensures that your platform stays at the forefront of financial technology, offering a competitive edge in today's fast-paced digital economy. By automating complex financial processes, you free your users to focus on growing their businesses while providing them with the tools they need to succeed.
Get Started with Crater
Transform your platform into a fintech powerhouse. Contact us today for a demo and discover how Crater can elevate your offering and drive user satisfaction.
A user-friendly desktop accounting software that helps businesses manage invoices, track expenses, and handle bookkeeping with a modern interface.

Frappe Books is a powerful desktop accounting solution that brings modern design and efficiency to business finances. The software runs locally on your computer, ensuring your financial data remains private and accessible even without internet connectivity.
Key features include:
The software combines professional accounting capabilities with an intuitive interface, making it ideal for small businesses and freelancers who want a reliable, no-cost solution for managing their finances.