Open-source PayPal alternatives

Hyperswitch is an open-source payments infrastructure written in Rust and released under the Apache-2.0 license. It is designed so businesses can pick only the modules they need and add them on top of an existing payment stack, without extra complexity or vendor lock-in. It is offered in both SaaS and self-hosted forms, and it connects to many payment, payout, fraud, vault and tokenization providers.

The modules include cost observability, with dashboards for detecting hidden fees, downgrades and penalties; revenue recovery, with configurable retry strategies to reduce passive churn; a vault service for storing cards, tokens, wallets and bank credentials, which the project describes as PCI-compliant and which can connect to existing providers; and intelligent routing that sends each transaction to a suitable payment processor, among them Stripe, Adyen, Braintree and Worldpay and over a hundred others.

The README also lists reconciliation to reduce payment operations work, a local quickstart, cloud deployment instructions and a hosted sandbox that needs no setup. It suits merchants, platforms and fintech teams that work with several payment processors and want more control over routing, costs and recovery than a single processor provides.

BTCPay Server is a free and open-source Bitcoin payment processor that you host yourself. It lets merchants accept Bitcoin directly from customers without relying on a third-party intermediary or paying processor fees, and the project positions it as a payment gateway for online stores and other businesses.

The README points users, operators, developers and maintainers to separate documentation tracks, and the project provides a Greenfield API for integrations and a plugin system for extensions. Repository topics mention the Lightning Network, point-of-sale and crowdfunding use cases alongside the payment gateway itself. A public demo, a community chat and a discussions forum support new users.

BTCPay Server is written in C# and released under the MIT licence. Security vulnerabilities must be reported through the private process described in the security policy instead of public issues. As with any self-hosted payment system, the operator is responsible for running and securing the server.