Tag
Payments
Billing, checkout, invoicing. 30 reviewed tools: 28 free or open source, 1 hosted with a real free tier, 1 paid or paid-led.
Order: free and open source first, then hosted products with a real free tier, then paid-led; catalog order inside each group, with quiet or archived repos last. Not a score, and no tool pays for its place.
30 tools
- Checkout UI ExtensionsCustomize Shopify checkout safely
Free / OSS · OSS/MIT
VerdictThe only way to customize checkout—work within the limits.
CatchThe sandboxed environment limits what is possible. Some desired customizations are not supported by extension points.
- Stripe CLIOfficial Stripe terminal for webhooks, events, and API objects
Free / OSS · Apache-2.0 · 2.2k GitHub stars
VerdictInstall it. Then still pay Stripe when money moves.
CatchThe CLI is free; card charges are not. See stripe.com/pricing for processing rates. Live mode needs a real secret. Dispute fees are on Stripe, not on this binary.
- PolarApache-2.0 merchant-of-record billing for indie and AI products
Free / OSS · Freemium · 10.4k GitHub stars
VerdictApache-2.0 MoR for indie and AI products. Free Starter, honest take-rate, real SDKs.
CatchNo first-party CLI in the docs index — SDKs, MCP, and API only. Starter take-rate sits on top of card-brand costs. Polar is MoR, so you do not keep the Stripe account relationship. International cards add extra. Payouts have their own cut.
- HyperswitchApache-2.0 payment orchestrator you can self-host
Free / OSS · Apache-2.0 · 45.4k GitHub stars
VerdictApache-2.0 payments orchestration. Self-host is free; PCI is not optional.
CatchCommunity Edition means you run PCI scope. Cloud and Self-Host Enterprise are Contact Us. The 500+ global enterprises line is Juspay production experience, not a Hyperswitch-customer logo wall.
- Kill BillApache-2.0 in-house subscriptions and payments, no % take-rate
Free / OSS · Apache-2.0 · 5.8k GitHub stars
VerdictApache-2.0 billing you run. Free until Aviate or the AMI; never a take-rate.
CatchJVM and ops-heavy. Aviate is the proprietary accelerator — not the Apache tree. Self-Hosted OSS Free; AWS Marketplace is ~$40/mo plus the AWS bill. No revenue tiles here because there is no % of revenue to quote.
- LagoAGPLv3 usage and entitlements metering you self-host
Free / OSS · AGPL-3.0 · 10.7k GitHub stars
VerdictAGPLv3 metering. Self-host or talk to sales — there is no hobby cloud.
CatchPremium is Contact us. There is no $0 Lago Cloud. Self-host is the free path; Cloud and Premium are quotes. AGPLv3 is network copyleft.
- BTCPay ServerMIT self-hosted Bitcoin/LN, 0% fees to your wallet
Free / OSS · OSS/MIT · 7.8k GitHub stars
VerdictMIT Bitcoin/LN checkout. 0% to the software; the node is yours.
CatchBitcoin and Lightning to your wallet — not card rails, not a PSP. Distinct from Polar (MoR cards) and Hyperswitch (card orchestration). You operate a node. Network miner fees still exist.
- MedusaMIT commerce OS you self-host; Cloud from $29/mo
Free / OSS · OSS/MIT · 36.8k GitHub stars
VerdictMIT commerce OS. Self-host is free; Cloud starts at $29/mo.
CatchCommerce OS, not invoices and not card rails. Cloud From $29/mo is not a $0 hobby hatch — self-host is the free path. Distinct from Polar/Hyperswitch (payments) and from Lago (metering).
- OpenMeterApache-2.0 usage-event metering; Cloud is Kong Konnect now
Free / OSS · AGPL-3.0 · 2.4k GitHub stars
VerdictApache-2.0 metering you compose locally. Hosted path is Kong; README is beta.
CatchCloud is now Kong Konnect Metering — check current Kong pricing on the vendor site. Distinct from Lago: usage-event metering first, not AGPL usage-billing with no hobby cloud. Compose is a local evaluation stack (Kafka/ClickHouse), not production topology.
- Spree CommerceBSD-3-Clause Ruby commerce OS; Free Sandbox, no platform fees
Free / OSS · Freemium · 15.8k GitHub stars
VerdictBSD-3 Ruby commerce. Self-host free; Sandbox has no CC. Not Medusa.
CatchRuby commerce + REST/OpenAPI + Next.js storefront — not Medusa MIT Node OS. Solidus (BSD sibling) omitted: same Spree-fork slot. Distinct from Medusa.
- SyliusMIT Symfony commerce; Plus is the commercial add-on
Free / OSS · Freemium · 8.6k GitHub stars
VerdictMIT PHP commerce on Symfony. Self-host is free; Plus is paid.
CatchSymfony + API Platform PHP headless — not Medusa MIT Node OS and not JS. Distinct from Medusa and Spree. Plus is commercial, priced on request.
- InvoiceShelfAGPL-3.0 self-host invoices, estimates, expenses, client portal
Free / OSS · AGPL-3.0 · 1.9k GitHub stars
VerdictAGPL SMB invoicing you host. Free forever; not a metering engine.
CatchSMB invoices/estimates/expenses/portal + Stripe on your server — not Kill Bill/Lago subscription orchestration or usage metering. Crater cut re-opened as InvoiceShelf. Distinct from Kill Bill and Lago.
- BagistoMIT Laravel/Vue commerce with marketplace and B2B
Free / OSS · OSS/MIT · 28.3k GitHub stars
VerdictMIT Laravel commerce. Self-host free. Not Medusa Node.
CatchLaravel/Vue commerce + marketplace/B2B — PHP twin to Medusa, not Medusa MIT Node OS. Sylius and Spree already cover Symfony/Ruby in Wave 5. Distinct from Medusa.
- PrestaShopOSL-3.0 classic PHP cart; pitch the core, not the module store
Free / OSS · OSS/MIT · 9.2k GitHub stars
VerdictOSL-3.0 PHP cart. Core is free; ignore the module upsell in the installer.
Catchinstaller may bundle optional SA commercial modules — pitch core only. Classic PHP cart, not headless Node (Medusa) and not Magento. Distinct from Medusa, Bagisto, Sylius, Spree.
- InkvoiceMIT freelancer invoicing; self-host primary, tiny Cloud Free
Free / OSS · Freemium · 30 GitHub stars
VerdictMIT freelancer invoices. Self-host free; Cloud Free is a teaser cap.
CatchFreelancer invoicing — not InvoiceShelf SMB suite, not Kill Bill subscription OS, not Lago usage metering. Distinct from InvoiceShelf, Kill Bill, and Lago.
- PaymenterMIT hosting billing; self-host free, cloud PaaS $5/mo paid
Free / OSS · Freemium · 2.8k GitHub stars
VerdictMIT hosting billing. Self-host free; cloud PaaS is $5/mo paid.
CatchVs Kill Bill/Lago/Polar: hosting webshop + provisioning (Pterodactyl/cPanel, WHMCS importer) — not generic subscription metering or Polar MoR. Cloud is $5/mo paid. Self-host is the $0 path.
- SolidInvoiceMIT Symfony invoicing; self-host free, Cloud trial paid
Free / OSS · Freemium · 979 GitHub stars
VerdictMIT Symfony invoicing. Self-host $0; Cloud trial/from $9 is paid.
CatchVs InvoiceShelf/Inkvoice: Symfony/PHP freelancer+SMB invoicing (quotes→invoices, payments, API/MCP). solidinvoice.co leads with 14-day Cloud trial / from $9/mo — free path is self-host ONLY.
- AutumnApache-2.0 Stripe billing layer; Free to 8K billing volume
Free / OSS · Freemium · 2.8k GitHub stars
VerdictApache-2.0 Stripe billing layer. Free tier real; still bring Stripe.
CatchVs Polar/Lago/OpenMeter: Stripe abstraction + entitlements — not Polar MoR, not Lago/OpenMeter metering-first. Stripe fees still apply. Pro Cloud from $375/mo. Free path is Free tier or self-host.
- Paddle CLIMIT community CLI for full Paddle Billing API; agent-native
Free / OSS · OSS/MIT · 1 GitHub stars
VerdictMIT Paddle Billing CLI. Free tool; Paddle merchant + MoR fees separate.
CatchCommunity CLI — not an official Paddle Inc product; API drift risk. Still need a Paddle merchant account (MoR fees apply). Vs Stripe CLI: Paddle-only. Thin MCP forks exist; this is the general CLI.
- Invoice NinjaELv2 source-available invoicing; self-host free, hosted Free 5 clients
Free / OSS · Open-Core · 10.3k GitHub stars
VerdictELv2 invoicing. Self-host free for your biz; hosted Free 5 clients / Pro paid.
CatchNOT OSI open source — ELv2 forbids offering it as competing hosted SaaS. Hosted Pro from ~$14/mo (2026 pricing). Vs Lago/Autumn: client invoicing, not usage metering/MoR. Attribution stays unless white-label.
- Stripe AIMIT official Stripe toolkit and MCP server for agents
Free / OSS · OSS/MIT · 2k GitHub stars
VerdictThe official way to give an agent Stripe actions — test mode and restricted keys first.
CatchTool calls act on your real Stripe account, so start in test mode with a restricted key. There are no GitHub releases — track the npm and PyPI packages instead. Vs stripe-cli (a terminal tool for developers to forward webhooks and inspect events): this is the toolkit an agent uses to call the Stripe API.
- lndMIT Lightning Network node daemon in Go
Free / OSS · OSS/MIT · 8.2k GitHub stars
VerdictThe reference choice when you want to run your own Lightning node.
CatchRunning a Lightning node means managing liquidity, channel backups and hot-wallet risk yourself; this is infrastructure, not a checkout button. Releases still carry a beta tag. For simple merchant payments a hosted processor or BTCPay-style layer on top is easier.
- PayMIT payments engine for Ruby on Rails
Free / OSS · OSS/MIT · 2.3k GitHub stars
VerdictThe obvious starting point for subscription billing in a Rails app.
CatchRails only. It wraps processor APIs instead of hiding them, so advanced Stripe features still need the Stripe gem directly. Switching processors later still involves real migration work.
- dj-stripeMIT Stripe data synced into Django models
Free / OSS · OSS/MIT · 1.8k GitHub stars
VerdictUse it when a Django app needs to reason about Stripe state locally.
CatchStripe only, and Django only. Model and Stripe API-version upgrades can require migrations and care. Releases are a few a year.
- MeteroidAGPL-3.0 usage-based pricing and billing platform
Free / OSS · AGPL-3.0 · 1.3k GitHub stars
VerdictA promising self-hostable option for metered SaaS billing.
CatchStill on release candidates before 1.0, so expect changes. AGPL matters if you modify and host it for others. Billing is high-stakes; compare it with Lago or Kill Bill before you commit.
- FOSSBillingApache-2.0 billing and client management for hosts
Free / OSS · Apache-2.0 · 1.7k GitHub stars
VerdictThe free WHMCS alternative to try if you sell hosting or similar services.
CatchThe README says it is beta, with rough edges and limited support. It is PHP and aimed at the WHMCS-style hosting market, so it is not a general SaaS billing engine.
- BigcapitalAGPL-3.0 self-hosted accounting and inventory app
Free / OSS · AGPL-3.0 · 3.9k GitHub stars
VerdictA credible open-source QuickBooks-style app for small businesses.
CatchStill pre-1.0. Accounting rules and tax features differ by country, so check that it covers yours before moving real books. AGPL applies if you modify and host it.
- Hyperswitch PrismApache-2.0 stateless library: one payment API for Stripe, Adyen and more
Free / OSS · Apache-2.0 · 1.4k GitHub stars
VerdictThe easy way to avoid locking your code to one payment processor — check the coverage table first.
CatchIt is only the translation layer: retries, smart routing and vaulting live in the full Hyperswitch platform, by design. Connector coverage varies by processor and payment method, and some cells are marked in progress or needs validation, so check the coverage table for your exact flows. Pre-1.0. PCI scope still depends on whether card data passes through your servers.
- pretixAGPL-3.0-with-additional-terms event tickets and POS
Free tier · Freemium · 2.5k GitHub stars
VerdictEvent tickets with a loud AGPL addendum. 500 free tickets/year hosted; 2.5% after that.
CatchAdditional terms: SaaS restrict (do not offer pretix as a service to third parties), footer attribution must stay, modified versions must not look official. Event tickets+POS, not subscriptions. Distinct from Polar (SaaS billing) and Lago (usage metering).
- KindeHosted auth plus billing, $0 forever, 10,500 MAU, no OSS
Paid-led · Freemium
VerdictHosted auth+billing with a real $0 forever plan. No repo to fork; branding until Pro.
CatchNot self-host. Kinde branding stays on Free. SMS is 10 included. Pro is $25/mo to uncap MAU and drop branding. Distinct from Polar (Apache MoR, not an IdP) and Clerk (auth UI, no 0.7% billing take-rate on Free).
FAQ
- What is the top free pick among Payments?
- Checkout UI Extensions leads the Stack Gems list for Payments. Verdict: The only way to customize checkout—work within the limits.
- How many Payments does Stack Gems review?
- 30: 28 free or open source, 1 hosted with a real free tier, 1 paid or paid-led. Each review has a verdict and an honest Catch; no tool pays for its spot.
- Which Payments can I self-host for free?
- Checkout UI Extensions, Stripe CLI, Hyperswitch, Kill Bill, Lago, BTCPay Server, Medusa, OpenMeter and 19 more.
- Which Payments have the most GitHub stars?
- Hyperswitch (45.4k), Medusa (36.8k), Bagisto (28.3k), per GitHub on 2026-10-19. Stars measure attention, not fit; read the Catch.
- What is the catch with Checkout UI Extensions?
- The sandboxed environment limits what is possible.