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Best Open-Source Budgeting Apps in 2026

A fair comparison of six open-source budgeting apps: Trout, Actual Budget, Firefly III, Maybe Finance, Paisa, and GnuCash. What each does well, where each falls short, and who each one is for.

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Six open-source budgeting apps are worth looking at in 2026. Each takes a different approach to managing money. Some use envelope budgeting. Others track transactions after the fact. One is a full double-entry accounting system from the 1990s that still works.

This roundup is written by the Trout team. We're one of the six apps listed. We've tried to be fair -- each app has genuine strengths we can't match. Read with appropriate skepticism and try the ones that interest you.

How we evaluated

Four criteria:

  1. Budgeting approach -- envelope/zero-based vs. traditional tracking vs. accounting
  2. Ease of setup -- how long from "I want to try this" to entering your first transaction
  3. Feature depth -- bank sync, rules, goals, reports, multi-currency
  4. Maintenance status -- active development, community size, recent commits

We did not test every feature of every app exhaustively. These assessments are based on documentation, source code, community discussions, and direct usage where possible.

1. Actual Budget

GitHub: 15,000+ stars | License: MIT | Language: JavaScript/TypeScript

Actual Budget is the most mature open-source envelope budgeting app. Originally a commercial product, it was open-sourced in 2022 and has been actively maintained by a community of contributors since.

How it works: Local-first architecture. Your budget data lives in a SQLite file on your device, with optional sync through a lightweight server. This means it works offline, which is rare for self-hosted apps.

What it does well:

  • Offline-first. Budget on a plane, in a subway, anywhere. Changes sync when you reconnect. This is a fundamental architectural advantage that other apps (including ours) can't easily replicate without rebuilding from scratch.
  • Mature and stable. Years of development and thousands of users have ironed out bugs and edge cases. The budgeting calculations are reliable.
  • End-to-end encryption. Your data can be encrypted client-side before syncing to the server. The server never sees your financial data in plaintext.
  • Simple deployment. Single Docker container or downloadable binary. No database server to manage. Setup takes 2-3 minutes.
  • Active community. 7,000+ Discord members, regular releases, responsive maintainers.
  • Bank sync. Supports GoCardless (Europe) and SimpleFIN (US) for automatic transaction import.

Where it falls short:

  • Limited transaction rules. Basic payee matching, no multi-condition logic or amount-based rules.
  • No AI features. No natural language queries or AI-assisted categorization.
  • SQLite limitations. For most users this is fine, but large datasets (tens of thousands of transactions) can slow down, and direct database querying is less powerful than PostgreSQL.
  • No crypto or investment tracking. Manual balance updates only.

Best for: People who want a proven, stable envelope budgeting app with offline support and minimal setup. If reliability and maturity matter more than newer features, Actual Budget is the safest choice.

2. Trout

GitHub: New project | License: FSL-1.1-MIT | Language: TypeScript

Trout is the newest app on this list. Full disclosure: we built it. It uses envelope budgeting with a modern TypeScript stack and includes features that other open-source budgeting apps don't offer. You can self-host it or use the free hosted version at trout.money.

How it works: Client-server architecture with Next.js frontend and Elysia API backend, backed by PostgreSQL. Deploys via Docker Compose.

What it does well:

  • AI financial assistant. Ask questions in plain English. "How much did I spend on dining this month?" The assistant queries your database and responds with actual numbers. No other open-source budgeting app has this.
  • Advanced transaction rules. Multi-condition rules with AND/OR logic, amount ranges, payee patterns, and memo matching. Significantly more capable than basic payee matching.
  • Native crypto tracking. Real-time portfolio values via CoinGecko, integrated into net worth calculations.
  • 2,500+ European bank connections. GoCardless Open Banking integration. Your bank credentials never pass through a third party.
  • Multi-currency with auto FX. Built-in exchange rate updates for budgeting across currencies.
  • Five goal types. More flexibility than any other option on this list.
  • Direct database access. PostgreSQL means you can run custom SQL queries, connect BI tools, or build integrations against a real relational database.

Where it falls short:

  • New project. Less battle-tested than Actual Budget or Firefly III. Expect rough edges and occasional bugs. The community is small.
  • No offline mode. Requires a connection to your server at all times. This is a real limitation for mobile use.
  • More complex setup. Docker Compose with PostgreSQL is more infrastructure than Actual Budget's single binary. You need to manage database backups yourself. (The hosted version eliminates this if you prefer not to self-host.)
  • No native mobile app. Responsive web only. No widgets, no push notifications, no offline transaction entry.
  • US bank sync not yet available. GoCardless covers Europe and UK. American users need to enter transactions manually or import CSV files.

Best for: European self-hosters who want envelope budgeting with AI, crypto tracking, and advanced automation. Developers who want a modern codebase they can contribute to.

3. Firefly III

GitHub: 17,000+ stars | License: AGPL-3.0 | Language: PHP

Firefly III is the elder statesman of open-source personal finance. Active since 2012, it's the most feature-complete option on this list -- but it takes a fundamentally different approach to budgeting.

How it works: Traditional transaction tracking with budgets applied on top, rather than envelope budgeting. Think of it as a personal accounting system. PHP backend with a Laravel framework.

What it does well:

  • Feature depth. Bills, piggy banks, recurring transactions, multi-currency, tags, attachments, splits, reconciliation. Firefly III has more features than any other app on this list. Years of development show.
  • Extensive API. Well-documented REST API that has spawned a third-party plugin community. Bank importers, Telegram bots, iOS clients -- the community has built tools on top of Firefly III's API.
  • Mature and stable. Over a decade of development. Thousands of users. The software is reliable and well-understood.
  • Strong documentation. Thorough docs at docs.firefly-iii.org covering every feature and configuration option.
  • Rule engine. Trigger-based rules that can set categories, tags, budgets, and more based on transaction content. More flexible than basic payee matching (though not as structured as Trout's AND/OR condition groups).
  • Double-entry bookkeeping. For users who want proper accounting, Firefly III supports it. This is overkill for most personal finance, but valuable for freelancers and small business tracking.

Where it falls short:

  • Not envelope budgeting. Firefly III uses traditional budgets -- set a spending limit per category, track against it. There's no "assign every dollar" methodology, no "Ready to Assign" balance, no rolling category balances in the YNAB sense. If you want envelope budgeting, Firefly III isn't the right tool.
  • Dated UI. The interface is functional but visually dated compared to newer apps. It works, but it looks like it was designed in 2015. (A redesign has been discussed but not shipped.)
  • Complex setup. PHP, MySQL/PostgreSQL, Redis, cron jobs. More infrastructure than most alternatives.
  • No AI features. No conversational assistant or AI-powered categorization.
  • No native crypto or investment tracking. Possible through manual accounts and third-party tools, but not built in.

Best for: Users who want a full-featured personal accounting system with maximum flexibility. Freelancers who need double-entry bookkeeping. People who don't like envelope budgeting but want control over their finances.

4. Maybe Finance

GitHub: 35,000+ stars | License: AGPL-3.0 | Language: Ruby on Rails

Maybe Finance has an unusual history. Originally built as a commercial product with over $1 million in development costs, it was open-sourced in 2024 when the company shut down. The community has since continued development.

How it works: Traditional financial tracking and net worth monitoring with an investment-heavy focus. Ruby on Rails backend.

What it does well:

  • Net worth tracking. Maybe's original design focused on wealth tracking. Account aggregation, investment performance, and net worth history are first-class features.
  • Clean UI. The commercial origins show. The interface is polished and well-designed, with quality data visualizations.
  • Investment focus. Better investment tracking than most budgeting apps. Shows portfolio performance, allocation, and historical returns.
  • Large GitHub presence. 35,000+ stars make it one of the most-starred personal finance projects on GitHub. (Stars partly reflect the viral story of open-sourcing $1M+ of development.)

Where it falls short:

  • Not envelope budgeting. No zero-based methodology. No category allocations. No "give every dollar a job." It tracks what happened rather than planning what should happen.
  • Uncertain maintenance. The original team is gone. Community contributors keep it alive, but the pace of development is slower than Actual Budget or Firefly III. Some features from the commercial version remain partially implemented.
  • Complex stack. Ruby on Rails, PostgreSQL, Redis, Sidekiq. Not trivial to self-host.
  • US-centric. Bank connections via Plaid. Limited utility outside the United States.
  • No transaction rules. Manual categorization for the most part.

Best for: Users focused on net worth tracking and investment performance who want a well-designed interface. People in the US who want Plaid bank sync with an open-source app.

5. Paisa

GitHub: 2,000+ stars | License: MIT | Language: Dart/Flutter

Paisa takes a completely different approach: it's a mobile-first budgeting app that runs as a native app on your phone. No server required.

How it works: Flutter app that stores data locally on your device using Hive (a lightweight local database). No cloud component at all unless you set up sync yourself.

What it does well:

  • True mobile app. Native Android and iOS app. This is the only fully native mobile option on this list. If you budget primarily from your phone, this matters.
  • Zero infrastructure. Install the app, start budgeting. No Docker, no servers, no databases to manage. The simplest setup on this list by far.
  • Offline by default. All data lives on your device. Works anywhere, always.
  • Clean mobile UI. Designed for phones from the start, not adapted from a desktop interface.
  • Multi-currency support. Good support for managing money across currencies.

Where it falls short:

  • No bank sync. All transactions are entered manually. No automatic import from any source.
  • No web interface. Phone-only. If you want to manage your budget on a desktop, Paisa doesn't support it.
  • Limited reporting. Basic charts and summaries. No advanced analytics or custom reports.
  • Smaller community. Fewer contributors and less community content than Actual Budget or Firefly III.
  • No envelope budgeting. Uses category-based tracking, not zero-based allocation.
  • Sync is DIY. If you want your data on multiple devices, you need to set up your own sync (Google Drive, Syncthing, etc.).

Best for: People who want a simple, phone-first budgeting app with zero technical setup. Users in areas with unreliable internet. Anyone who finds self-hosting intimidating but still wants open-source software.

6. GnuCash

GitHub: 5,000+ stars | License: GPL-2.0 | Language: C/C++

GnuCash has been around since 1998. It's a full double-entry accounting application that can handle personal finances, small business bookkeeping, and everything in between.

How it works: Desktop application (Windows, macOS, Linux) with a traditional accounting interface. Stores data in XML or SQLite files locally.

What it does well:

  • Full accounting. Double-entry bookkeeping with proper debits and credits, balance sheets, income statements, and accounts receivable/payable. This is real accounting software, not a simplified budgeting app.
  • 27+ years of development. The most mature option on this list by far. Stable, well-tested, extensively documented.
  • No internet required. Fully local. Your data never touches a network.
  • Stock and investment tracking. Price quotes, capital gains tracking, and portfolio reports. More accounting-correct than any other option here.
  • Multi-currency. Proper currency accounts with exchange rate tracking. Used by accountants and businesses globally.
  • Extensive import. OFX, QIF, CSV, and more. Bank downloads work through file import.

Where it falls short:

  • Not a budgeting app. GnuCash is accounting software. There's no envelope budgeting, no zero-based methodology, no "Ready to Assign." You can create budgets, but they're accounting budgets (track spending against limits), not envelope budgets.
  • Steep learning curve. Understanding double-entry bookkeeping is a prerequisite. If "debit" and "credit" confuse you, GnuCash will be frustrating.
  • Desktop-only. No web interface, no mobile app (the abandoned Android app is unmaintained). There's no way to access your data from a phone.
  • Dated interface. The UI looks like it was designed in 2005 because it was. Functional, but not pretty.
  • No bank sync. File-based import only. No automatic connection to your bank.
  • No collaboration. Single-user only. The file-based storage doesn't support multiple simultaneous users.

Best for: Users who want real double-entry accounting for personal finances or a small business. People who already understand bookkeeping and want a free alternative to QuickBooks. Absolutely not for budgeting beginners.

Comparison table

| Feature | Actual Budget | Trout | Firefly III | Maybe Finance | Paisa | GnuCash | |---------|:---:|:---:|:---:|:---:|:---:|:---:| | Envelope budgeting | Yes | Yes | No | No | No | No | | Bank sync | Yes | Europe only | Via importers | US only | No | No | | Offline mode | Yes | No | No | No | Yes | Yes | | Mobile app | PWA | Responsive web | None | Responsive web | Native | No | | AI assistant | No | Yes | No | No | No | No | | Transaction rules | Basic | Advanced | Advanced | No | No | No | | Crypto tracking | No | Native | No | No | No | No | | Multi-currency | Yes | Yes | Yes | Limited | Yes | Yes | | Investment tracking | No | Paused | No | Yes | No | Yes | | Deployment | Docker/binary | Docker Compose or hosted | Docker/PHP | Docker | Mobile app | Desktop install | | Community size | Large | Small | Large | Medium | Small | Large | | Active development | High | High | High | Medium | Medium | Medium |

Our recommendation by user type

"I want YNAB but free" -- Start with Actual Budget. It's the closest to YNAB in approach and maturity, with the added benefit of offline support. If you want more advanced features (AI, rules, crypto), try Trout.

"I want full control over my financial data" -- Firefly III if you want maximum features and don't care about envelope budgeting. Trout if you want envelope budgeting with direct PostgreSQL access.

"I just want something on my phone" -- Paisa for a native mobile app with zero setup. Or Actual Budget for a PWA that works well on mobile.

"I'm a developer and want to contribute" -- Trout (TypeScript/Next.js/Elysia) or Actual Budget (JavaScript/TypeScript) depending on which stack you prefer. Firefly III if you like PHP/Laravel.

"I need real accounting" -- GnuCash. Nothing else on this list does proper double-entry bookkeeping. Firefly III comes close but GnuCash is the standard.

"I want investment and net worth tracking" -- Maybe Finance for polished investment visualization. GnuCash for accounting-correct investment tracking.

Every app on this list is free and open source. Try the ones that match your needs. The best personal finance tool is the one you'll actually use consistently, and that depends on your workflow, your priorities, and what kind of budgeting approach clicks with how you think about money.