The 14 Best Open Source Payment Processing Software, Ranked & Reviewed for 2025
The Top 10 Open Source Payment Processing Software
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Running payments in a real business isn’t just about taking cards—it’s about control, transparency, and not getting fleeced by every transaction. If you’ve ever had to chase down failed settlements or explain mystery fees to your CFO, you already know what’s at stake.
Open source payment processing gives you the flexibility to cut out the middle layers, tailor workflows to your business, and avoid vendor lock-in.
It’s not for everyone—you’ll need some technical chops—but the payoff is worth it.
Need expert help selecting the right tool?
With one-on-one help, we guide you to your top software options. Narrow down your software search & make a confident choice.
In this guide, I’ve pulled together the top open source platforms that actually deliver: real-time data, API-first builds, modular pricing, and serious security. No fluff, no filler—just the tools that let you own your payment stack.
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Comparing the Best Payment Processing Software Open Source Side-by-Side
Quick side-by-side of top picks. Compare pricing and use cases to find the right fit—fast.
| Tool | Best For | Trial Info | Price | ||
|---|---|---|---|---|---|
| 1 | Best for developers needing simple APIs | Free plan available | From $5/month | Website | |
| 2 | Best for intelligent payment routing | Free plan available | Pricing available upon request | Website | |
| 3 | Best for no-fee cryptocurrency transactions | Free plan available | From $0/month | Website | |
| 4 | Best for PHP-based integration needs | Free plan available | Free (open-source) | Website | |
| 5 | Best for privacy-friendly transactions | Free plan available | Pricing available upon request | Website | |
| 6 | Best for large merchant custom gateways | Free demo available | From $50,000 (one-time license fee) | Website | |
| 7 | Best for usage-based billing setups | Free plan available | From $19/month | Website | |
| 8 | Best for usage-based billing | 7-day free trial available | 4% plus 40¢/transaction | Website | |
| 9 | Best for ACH transfers in the US | Free demo available | From $49/month | Website | |
| 10 | Best for fee-free Bitcoin transactions | Free demo available | Pricing available upon request | Website |
The 10 Best Open Source Payment Processing Software, Reviewed
Here’s the full breakdown of every open source payment processor that made the cut. I focused on what matters: real-world functionality, integration flexibility, pricing transparency, and how each one actually performs in practice.
UniBee is an API-first platform built for developers who need to send, receive, and manage payments without a lot of overhead. It’s used by teams looking for a lightweight way to plug payments into apps and services. The tool focuses on keeping integration simple while offering flexibility in how payments are handled.
Why I picked UniBee: It’s made for developers who want clean, easy-to-use APIs without getting locked into a complex system. UniBee supports multiple payment types and lets you handle everything—from invoice creation to status tracking—via direct API calls. There’s no bloated dashboard or rigid workflows, so your team can build exactly what you need. You can also run local tests and simulate webhooks, which speeds up development and debugging.
Standout features & integrations:
Features include real-time webhook simulation so you can test payment flows without live traffic. There’s CLI support for managing payments from your terminal. You also get detailed API logs to help troubleshoot issues as they come up.
Integrations include Stripe, PayPal, Razorpay, Coinbase Commerce, Wise, Slack, Discord, Notion, GitHub, and Zapier.
Pros and cons
Pros:
- Flexible setup across payment types
- CLI tools simplify integration work
- Fast to test and deploy payment flows
- Clean API-focused design for developers
Cons:
- No advanced fraud or compliance tools
- Few visual configuration options
- Not ideal for non-technical users
Hyperswitch is an open-source payment platform designed for businesses wanting control over their payment systems. It serves businesses of all sizes, offering features like intelligent routing and secure payment data storage.
Why I picked Hyperswitch: It stands out with its intelligent routing, which improves authorization rates, and a unified reconciliation engine that simplifies financial management. The platform includes revenue recovery to reduce customer churn, making it ideal for businesses focusing on customer retention. Its cost observability feature helps you track payment expenses effortlessly, aligning with its USP of intelligent payment routing.
Standout features & integrations:
Features include intelligent routing for better authorization, a unified reconciliation engine to streamline financial processes, and secure vaulting for payment data. These features help your team manage payments efficiently and reduce operational hassles.
Integrations include Stripe, PayPal, Braintree, Adyen, Worldpay, Klarna, Amazon Pay, Square, Apple Pay, and Google Pay.
Pros and cons
Pros:
- Customizable authentication workflows
- Supports 300+ integrations
- Secure payment data vaulting
- Intelligent routing improves authorization
Cons:
- Advanced features can be overwhelming
- Not ideal for very small businesses
- Limited support for niche payment methods
Bitcart is a non-custodial, open-source cryptocurrency payment processor designed for businesses and individuals wanting to accept crypto payments directly. It performs key business functions like accepting payments in various cryptocurrencies without third-party involvement.
Why I picked Bitcart: It offers a unique no-fee structure, which is a significant advantage for cost-conscious users. The platform supports multiple cryptocurrencies, including Bitcoin and Ethereum, ensuring flexibility in payment options. Its user-friendly admin panel makes it easy for you to manage payments without technical hassle. Additionally, the powerful SDK allows for custom app development, aligning with its USP of no-fee transactions.
Standout features & integrations:
Features include a user-friendly admin panel for easy management, support for the lightning network to enhance transaction speed, and a powerful SDK for developing custom applications. These features make Bitcart a versatile tool for handling cryptocurrency payments.
Integrations include support for classical blockchains and smart contract platforms, enabling seamless integration with various cryptocurrencies.
Pros and cons
Pros:
- Supports multiple cryptocurrencies
- Open-source and customizable
- Easy to deploy and use
- Secure and private
Cons:
- Initial setup can be complex
- May need technical skills
- Requires self-hosting
Payum is a PHP payment processing library designed for developers integrating various payment gateways into their applications. It's primarily used by teams building custom ecommerce or billing solutions that require flexibility and control over payment workflows. The library supports a wide range of payment services and provides tools for handling transactions, subscriptions, and notifications.
Why I picked Payum: It’s built for developers who need to integrate multiple payment gateways without being tied to a specific provider. Payum offers a unified API that allows you to work with different payment services like PayPal, Stripe, and Authorize.Net using consistent code patterns. You can manage recurring payments, handle instant payment notifications, and process refunds through its extensible architecture. The library also provides secure token-based workflows to manage payment sessions and callbacks. Its modular design lets your team customize and extend functionality as needed.
Standout features & integrations:
Features include support for both on-site and off-site payment processing, giving your team flexibility in handling transactions. It provides tools for managing payment statuses, so you can accurately track the state of each transaction. Payum also includes storage extensions compatible with various PHP frameworks, helping you integrate payment data management into your existing systems.
Integrations include PayPal, Stripe, Authorize.Net, Klarna, Be2Bill, Payex, Sofort, Omnipay, Braintree, and Mollie.
Pros and cons
Pros:
- Compatible with various PHP frameworks
- Secure token-based workflows
- Customizable and extensible architecture
- Unified API for different services
Cons:
- No official support for non-PHP environments
- Needs manual setup for each gateway
- Requires PHP development experience
Taler is an open-source payment system designed for online transactions that prioritizes privacy and data protection. It is suitable for businesses and communities looking to manage their payment infrastructure without the need for user registration.
Why I picked Taler: It differentiates itself by eliminating fraud through its design, which makes transactions secure and private. The system does not introduce a new currency, ensuring compatibility with existing financial systems. Its free software nature empowers communities to run their payment systems independently. The focus on privacy and security aligns with its USP, making it a unique choice for privacy-conscious users.
Standout features & integrations:
Features include payments without registration, which simplifies user interaction and enhances privacy. It also offers data protection by default, ensuring your transactions are secure. The design eliminates fraud, providing peace of mind for your transactions.
Integrations include the ability to integrate with various existing financial systems and infrastructures, allowing for a seamless transition and operation.
Pros and cons
Pros:
- Free and open-source software
- Community-run infrastructure
- No registration required for payments
- Privacy-focused transaction design
Cons:
- Focused mainly on privacy-conscious users
- Requires understanding of privacy tools
- Not widely adopted yet
UniPay is a payment gateway platform designed for large merchants and organizations that require customizable payment processing solutions. It's commonly utilized by businesses seeking to manage complex payment operations, including merchant onboarding, transaction processing, and compliance management. The platform offers a range of deployment options to accommodate various business needs.
Why I picked UniPay: It's tailored for teams that need a flexible payment infrastructure capable of adapting to specific operational requirements. UniPay provides options for white-label solutions, on-premise deployments, and support for payment facilitation models. Your team can leverage its APIs to integrate with existing systems and customize workflows. The platform also includes tools for managing recurring billing, chargebacks, and multi-currency transactions.
Standout features & integrations:
Features include support for recurring billing, enabling your team to automate subscription-based payments. It offers tools for chargeback management, helping you handle disputes efficiently. UniPay also provides multi-currency processing capabilities, allowing you to accept payments from customers in different countries.
Integrations include Authorize.Net, Elavon, Heartland Payment Systems, Paysafe, Eightcap, CREDITONLINE, Aussie Time Sheets, Salesforce, NetSuite, and Microsoft Dynamics 365.
Pros and cons
Pros:
- Multi-currency processing
- Comprehensive API access
- Supports complex payment models
- Customizable deployment options
Cons:
- Steep learning curve for new users
- Complex integration process
- Limited out-of-the-box analytics
Lago is a billing platform built for teams that need to track and charge for usage across complex pricing models. It’s used by companies that want to combine subscriptions, pay-as-you-go, and prepaid credits without building everything from scratch. The product handles metering, pricing, invoicing, and payments through APIs or a self-hosted setup.
Why I picked Lago: It’s made for teams that need to track and charge for usage across complex pricing models. You can meter events in real time, define custom pricing tiers, and automate invoices with taxes and credits applied. Lago supports hybrid models, like combining a base subscription with usage-based overages or prepaid bundles. It also offers both cloud and open-source self-hosted options, so your team can choose how much control they want over your billing infrastructure.
Standout features & integrations:
Features include instant add-ons that let you charge one-time fees without waiting for the next billing cycle. You can create and manage coupons to offer discounts or promotions. Lago also supports credit notes and refunds, helping your team handle adjustments and returns without extra tools.
Integrations include Stripe, GoCardless, Adyen, Salesforce, HubSpot, NetSuite, Xero, Anrok, Zapier, and AWS Marketplace.
Pros and cons
Pros:
- Works well with prepaid credits and add-ons
- API-first design for developer control
- Real-time event metering at high scale
- Open-source with cloud or self-hosted options
Cons:
- Few built-in analytics or dashboards
- UI is not ideal for non-technical users
- Limited visual reporting for finance teams
Polar is an open-source payment processing software designed for modern SaaS and digital product sales. It caters to businesses needing flexible billing solutions and effective customer management.
Why I picked Polar: It excels with its usage-based billing through a robust API, automating access to various features. The platform handles tax compliance, acting as a global merchant of record, which is crucial for international sales. Its integration with frameworks like Next.js ensures secure checkouts and customer portals. The developer-friendly experience and responsive support further enhance its appeal for tech-savvy businesses.
Standout features & integrations:
Features include flexible pricing models for digital and subscription products, automatic customer creation, and a benefits engine for automating access to features. These features simplify the billing process and enhance customer management for your team.
Integrations include Raycast, Framer, Zapier, Stripe Connect, LemonSqueezy, and Next.js.
Pros and cons
Pros:
- Efficient migration process
- Developer-friendly experience
- Handles tax compliance globally
- Usage-based billing available
Cons:
- Not ideal for offline sales
- Transaction fees can add up
- Limited to specific frameworks
OpenACH is a payment platform built to handle direct ACH bank transfers in the U.S. It’s used by businesses that need to move money through the banking system without using credit card networks. The tool covers everything from initiating transactions to managing returns and settlements.
Why I picked OpenACH: It’s designed around U.S. ACH payments, so your team can send and receive bank transfers without patching together multiple services. OpenACH gives you direct file creation and transmission to the Federal Reserve, without going through a third-party processor. You can manage returns, rejections, and transaction batching all within the same tool. It also supports NACHA file formatting and scheduling, so you can run payments on your timeline.
Standout features & integrations:
Features include detailed return code tracking so you can follow up on failed transfers quickly. You can manage multiple originators and accounts in one place. There’s also support for recurring entries, which helps if you need to run the same transactions regularly.
Integrations include QuickBooks, Xero, Zoho Books, FreshBooks, Odoo, Sage, NetSuite, Microsoft Dynamics 365, Salesforce, and Stripe.
Pros and cons
Pros:
- Handles multiple bank accounts at once
- Detailed return code management
- Works without third-party processors
- Full control over ACH file creation
Cons:
- UI feels outdated for some users
- Not built for international transfers
- Setup needs ACH and NACHA file knowledge
BTCPay Server is an open-source cryptocurrency payment processor designed for ecommerce businesses and individuals wanting to accept Bitcoin payments directly. It performs key business functions like invoicing, point-of-sale, and crowdfunding while offering secure and fee-free transactions.
Why I picked BTCPay Server: It provides a self-hosted solution that ensures privacy and censorship resistance, which is vital for secure transactions. The platform includes built-in apps for diverse payment needs and supports native wallet management. Its API automation makes it easy for you to customize payment processes. Plus, you can choose to self-host or use a shared server, catering to both tech-savvy and non-technical users.
Standout features & integrations:
Features include point-of-sale systems for seamless transaction handling, crowdfunding tools for raising funds directly in Bitcoin, and native wallet management for secure payment storage. These features ensure you can manage your Bitcoin payments effectively and securely.
Integrations include WooCommerce, Shopify, Magento, PrestaShop, Drupal, Odoo, WordPress, Joomla, OpenCart, and WHMCS.
Pros and cons
Pros:
- API for customization
- Supports diverse payment needs
- Self-hosting ensures privacy
- Fee-free Bitcoin transactions
Cons:
- Relies on Bitcoin network stability
- May need server maintenance
- Limited to Bitcoin payments
Other Open Source Payment Processing Software
Here are some additional open source payment processing software options that didn’t make it onto my shortlist, but are still worth checking out:
Our Selection Criteria for Open Source Payment Processing Software
Choosing open source payment software isn’t about checking boxes—it’s about knowing which trade-offs are worth it. Here’s how I broke it down:
Core functionality (25% of total score)
This is the bare minimum—if it doesn’t do these well, it didn’t make the list.
- Processes online and in-app payments securely.
- Supports multiple currencies and payment methods.
- Generates transaction records and invoices reliably.
- Provides real-time payment status and reporting.
Additional standout features (25% of total score)
This is where great tools pull ahead of the pack.
- Customizable workflows to match your ops, not the other way around.
- API-first architecture for smoother dev handoffs.
- Built-in support for subscription billing, crypto, or ACH if that’s your jam.
- Real-time analytics and fraud prevention that don’t require another plugin.
Usability (10% of total score)
If your team can’t use it, it doesn’t matter how powerful it is.
- Clear interface that doesn’t feel like a sysadmin dashboard.
- Logical navigation that supports everyday workflows.
- Minimal ramp-up for devs and operators alike.
Onboarding (10% of total score)
Setup should take hours—not a quarter.
- Templates, guides, or videos to speed up configuration.
- Sandbox environments or live demos for safer trial runs.
- Docs that don’t require guessing or Slack support threads.
Customer support (10% of total score)
Even open source tools need someone to talk to when things break.
- Clear support channels, even if it’s just GitHub Issues.
- Reasonable response times and active community forums.
- Access to paid support tiers or SLAs for high-stakes teams.
Value for money (10% of total score)
Free is great—but not if it burns hours in dev time.
- Transparent pricing with no surprise fees.
- Features that justify upgrade costs or paid tiers.
- Open-source flexibility that offsets vendor costs.
Customer reviews (10% of total score)
What real users are saying behind the star ratings.
- Comments on stability, dev experience, and community.
- Specifics on performance at scale or during growth.
- Feedback on updates, bugs, and long-term support.
What is Open Source Payment Processing Software?
Open source payment processing software is a customizable tool for handling online payments. It’s built for businesses that want more control over how money moves—without relying on black-box SaaS vendors.
You get access to the source code, which means you can adapt it to your workflow, your security needs, and your pricing structure.
If you’ve worked in ecommerce or had to reconcile a dozen payment reports manually, you know why this matters. These tools are built to be developer-friendly, API-first, and endlessly configurable.
You can integrate them with your existing systems, route transactions however you want, and even host everything yourself if compliance or cost is a concern.
It’s not plug-and-play, and it’s not for everyone. But if you’ve got the team—or the grit—to take control of your payments stack, open source options can give you enterprise-grade power without the enterprise-grade markup.
How to Choose Open Source Payment Processing Software
Not all open source payment tools are created equal. Some are dev-first and flexible; others look great on GitHub but fall apart in real operations.
This table breaks down the key factors to help you cut through the noise and focus on what actually matters for your business.
| Factor | What to look for |
|---|---|
| Scalability | Can it handle peak traffic, growth, and multichannel expansion without choking? |
| Integrations | Connects cleanly with your stack—think CRM, accounting, ecommerce, and gateways. |
| Customizability | Lets your devs tailor workflows, dashboards, and APIs without fighting the code. |
| Ease of use | Intuitive enough that ops and finance don’t need a cheat sheet to run reports. |
| Implementation | Has clear docs, sandbox environments, and support if your team hits a wall. |
| Cost | Transparent pricing. Watch for per-user fees, gateway markups, and upgrade traps. |
| Security | PCI DSS compliance, encryption, and fraud tools that don’t require a plugin hunt. |
| Compliance | Meets regional and industry standards—especially if you're handling cross-border. |
Features of Open Source Payment Processing Software
Look beyond the buzzwords. These are the features that make or break a payment platform when you're trying to keep money moving and your team sane:
- Integration capabilities. Works with your existing ecommerce, accounting, CRM, and ERP tools—no duct tape required.
- API-first architecture. Gives developers real control to build, extend, and automate workflows across your payment stack.
- Customizable workflows. Tailor how payments are triggered, approved, and tracked based on your actual ops—not some vendor’s defaults.
- Multi-currency and payment method support. Accepts credit cards, ACH, crypto, wallets, and more—without extra fees or Frankenstein plugins.
- Secure transaction handling. Comes with strong encryption, PCI DSS compliance, and anti-fraud tools out of the box.
- Real-time analytics. Track payments, monitor trends, and catch failures before your customers do.
- Scalability. Handles spikes, growth, and international expansion without requiring a rebuild.
- Open-source flexibility. Full access to the source code so your team can modify, fork, or self-host as needed.
- Community-backed updates. Built and improved by active devs—because no one wants abandonware running their cashflow.
Benefits of Open Source Payment Processing Software
The upside isn’t just about saving money—it’s about owning your stack and staying flexible as your business evolves. Here’s what you really get:
- Cost control. No license fees, no bloated per-user pricing, and transparent transaction costs.
- Full flexibility. Customize everything from APIs to workflows without waiting on a vendor roadmap.
- Better security posture. Self-hosting and open code mean you control who sees what—plus easier PCI DSS alignment.
- Faster scaling. Add currencies, methods, or business units without begging for an enterprise upgrade.
- Global readiness. Accept credit cards, debit cards, wallets, ACH, and crypto—all on your terms.
- Developer efficiency. Cleaner APIs and documentation = fewer hacks, faster launches, and less reliance on support tickets.
- No vendor lock-in. Change providers, integrations, or architecture without replatforming your entire payments system.
Costs and Pricing of Open Source Payment Processing Software
Open source doesn’t mean free across the board. Some tools charge for hosting, plugins, or enterprise features—others come with SDKs and support tiers.
Here’s how typical plans break down, plus what to watch for when budgeting.
| Plan type | Average price | Common features | Best for |
|---|---|---|---|
| Free plan | $0 | Basic payment processing, community support, limited integrations, GitHub docs | Developers or side projects |
| Starter | $5–$25/month | API access, usage-based billing, sandbox testing, plugin modules | Small teams or early-stage SaaS |
| Business | $30–$75/month | Subscription billing, real-time analytics, refunds, authentication workflows | Growing online businesses |
| Enterprise | $100–$200+/month or license | White-label setup, PSP and acquirer integrations, advanced security, SDK access | High-volume or multi-region ops |
Heads up: Some providers charge transaction fees, per-user pricing, or require paid add-ons for crypto support, wallets, or recurring billing. If you’re handling multiple payment methods or planning to self-host, factor in setup time and dev costs.
Payment Processing Software Open Source FAQs
Here are some answers to common questions about payment processing software open source:
Can I connect open source payment software to legacy systems?
Yes, as long as you’ve got developers who can work with APIs or SDKs. Most open source platforms are built with integration in mind, so it’s possible to tie into older POS systems or ERPs. Just plan for some upfront dev time—it’s not a plug-and-play situation.
What’s the difference between a PSP and a payment processor?
A PSP (payment service provider) handles the whole stack—gateway, processing, and acquiring—while a payment processor just moves funds. With open source tools, you can build a PSP-lite setup that gives you more control and fewer middlemen.
Is self-hosting open source payment software worth it?
If you care about control, compliance, or avoiding vendor fees, it usually is. Self-hosting gives you full ownership over the stack, but you’ll need infrastructure and someone on your team who can manage it.
How do chargebacks and disputes work with open source systems?
You won’t get a built-in chargeback wizard. Some tools offer plugins or modules, but in most cases, you’ll manage disputes through your processor or custom workflows. It works—you just have to build it out.
Can I use these tools if I’m outside North America?
Yes, many platforms support multi-currency payments and international gateways. But if you’re relying on ACH or region-specific acquirers, make sure the tool supports those workflows in your country.
How do updates and patches work with open source platforms?
You’re in charge. Most platforms post updates on GitHub and have active communities, but it’s your responsibility to apply them—especially security patches. The upside: you control the timeline and what gets deployed.
Open Source, Closed Loops
Payments shouldn’t feel like a mystery charge on your own statement. Open source tools give you clarity, control, and the flexibility to scale without locking yourself into someone else’s pricing model—or tech stack.
Whether you need real-time routing, subscription billing, or just a cleaner way to handle credit cards and ACH, there’s an open source option here that’ll fit your flow.
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