Open Source FastSpring Alternatives

Spree Commerce is an open source headless eCommerce platform designed for businesses that need flexibility, control, and the ability to handle complex commerce scenarios. Whether you're building a B2B wholesale portal, multi-vendor marketplace, or cross-border operation, Spree provides a battle-tested commerce engine with complete REST API access and zero platform fees.

Key capabilities include:

• B2B Commerce: Custom price lists, buyer organizations, purchase approvals, and net payment terms
• Multi-vendor Marketplaces: Vendors manage products while you control payouts and commissions
• Multi-tenant Architecture: Embed commerce into your SaaS or franchise network
• Multi-store & Multi-region: Run multiple brands or sell cross-border with localized pricing and tax rules
• Flexible Pricing Engine: Volume tiers, customer-specific pricing, and time-based promotions
• Advanced Product Management: Unlimited products, variants, and rich media with flexible data models
• Global by Default: Multi-currency, multi-language, EU Omnibus compliance, and Translations Center built in
• Configurable Promotions: Sophisticated rules, coupon codes, automatic discounts, and gift cards
• Payment Flexibility: Connect any provider (Stripe, Adyen, PayPal) with 3D Secure and PCI compliance

For developers, Spree offers complete REST APIs with OpenAPI 3.0 documentation, a TypeScript SDK, production-ready Next.js storefront, and extensible architecture through events, webhooks, and dependency injection. The platform is AI-ready with CLI tools and MCP server support.

For businesses, Spree eliminates vendor lock-in with zero platform fees, no GMV cuts, and complete ownership of your stack. Deploy anywhere—AWS, GCP, Azure, or your own data centers. Enterprise Edition includes dedicated support, advanced security, and compliance-ready controls for mission-critical operations.

Gumroad is a powerful platform that empowers creators to monetize their digital products directly to their audience. The platform offers:

• Simple Setup: Launch your digital storefront in minutes with no technical knowledge required
• Flexible Product Types: Sell ebooks, courses, software, templates, music, and more
• Built-in Tools: Get analytics, email marketing, and audience management features
• Creator-First Approach: Keep up to 95% of your revenue with industry-low fees
• Automated Delivery: Instant digital delivery and license key management
• Global Reach: Sell to customers worldwide with multiple currency and payment options

The platform handles all the technical aspects like payment processing, file hosting, and delivery, letting creators focus on what they do best - creating valuable content.

Polar is a complete payment infrastructure built for modern digital businesses. Key features include framework-specific adapters that enable integration in under a minute, particularly with Next.js for secure checkouts and customer portals. The platform offers sophisticated usage-based billing with built-in support for LLM token tracking and custom ingestion strategies.

The system handles all aspects of digital commerce including:

• Full tax compliance as Merchant of Record, managing VAT, GST, and sales tax globally
• Automated product benefits like license keys, digital downloads, and GitHub/Discord access
• Developer-friendly tools including CLI commands for quick setup and migration
• Flexible pricing models with support for subscriptions and one-time purchases
• Open source integrations with Raycast, Framer, and Zapier

With competitive pricing at 4% + 40¢ per transaction, Polar provides a modern alternative to traditional payment processors, focusing specifically on the needs of digital product creators and SaaS businesses.

Flexible billing infrastructure designed for modern SaaS companies at any stage of growth. This open-source platform eliminates billing headaches by providing a comprehensive solution that separates pricing logic from payment processing.

Key capabilities include:

• Complex pricing modeling - Handle usage-based, tiered, and hybrid pricing models with ease
• Real-time metering - Track API requests, tokens, and custom usage metrics across services
• Automated invoicing - Generate and send invoices automatically based on usage and pricing rules
• Multi-tenancy support - Scale effortlessly across diverse customer bases
• Localized pricing - Customize offerings for global markets with regional pricing

Developer-friendly features:

• RESTful APIs and webhooks for seamless integration
• Feature flags for controlled rollouts
• Audit trails for complete transparency
• Real-time data ingestion for instant insights

Modular architecture allows you to use the entire platform or pick specific modules that fit your needs. Built by an active open-source community with backing from the French State's France 2030 program, ensuring long-term sustainability and continuous innovation.