battles / Checkout
FastSpring vs Rally
FastSpring ($750/mo/mo, vibe code 3/10) vs Rally ($750/mo/mo, vibe code 4/10). FastSpring is the easier one to rebuild yourself — here is what you lose either way.
Checkout
$750/mo/mo
- MVP
- 2 weeks
- Full replacement
- Never (Requires global tax entities, banking rails, legal indemnification)
easier to rebuild
get the build prompt →Checkout
$750/mo/mo
- MVP
- 3-4 weeks
- Full replacement
- 6-12 months, due to PCI-DSS compliance, multi-gateway token vaulting, and complex cart/tax reconciliation edge cases.
price gap / year
usage-based
running both / year
$18,000/mo
our call
Start with FastSpring — highest vibe code, weakest moat.
FastSpring
FastSpring is not just checkout software; it assumes legal and financial liability as the Merchant of Record. Rebuilding the checkout UI in React is trivial, but self-hosting global VAT/GST compliance, localized payment acquirers, and fraud liability requires massive legal infrastructure.
you can rebuild
- Embeddable checkout UI modal and hosted payment pages
- Basic subscription management and recurring billing webhooks
- License key generation and digital file fulfillment triggers
- Customer portal for invoice downloads and subscription cancellations
- Multi-currency storefront price conversion displays
what you lose
- Merchant of Record legal status and cross-border indirect tax liability assumption
- Automated VAT/GST calculation, collection, and filing across 200+ global jurisdictions
- Global payment gateway routing, localized payment methods (iDEAL, Pix, Alipay), and acquirer optimization
- Merchant-level chargeback and fraud liability protection
- Payer of record status handling international currency conversion payouts
real moats
- Global legal and tax registration network with local tax authority filings
- Underwritten acquiring bank relationships and payment processing infrastructure
- Financial liability indemnification for chargebacks, VAT audits, and sanctions checks
open source escape hatches
- Kill Bill Apache-2.0
- Lago AGPL-3.0
- Hyperswitch Apache-2.0
Rally
Rally handles secure payment tokenization, multi-gateway routing, and post-purchase order mutations across platforms. Building a basic React checkout form is trivial; maintaining a PCI-compliant, fault-tolerant payment architecture that processes post-purchase upsells without re-prompting for card details is high-risk engineering.
you can rebuild
- Post-purchase upsell modal presentation and product selection UI
- Custom checkout page layout and visual design elements
- Basic promotional discount and coupon input handling
- Address auto-complete and client-side form validation
- Custom checkout form field injection
what you lose
- Out-of-the-box PCI-DSS compliance isolation for payment processing
- Native post-purchase authorization holding and order modification logic
- Pre-integrated connections to tax engines (Avalara/TaxJar) and shipping rate APIs
- Cross-merchant 1-click user recognition network
- Battle-tested zero-downtime performance during high-concurrency product drops
real moats
- PCI-DSS Level 1 compliance infrastructure and audit coverage
- Deep ecosystem integrations with payment gateways, tax providers, and fraud platforms
- Shared buyer payment token vault across merchant networks
open source escape hatches
- MedusaJS MIT
- Saleor BSD-3-Clause
- Spree Commerce BSD-3-Clause
Questions people ask
Which is easier to rebuild with AI, FastSpring or Rally?
FastSpring. It scores 3/10 on vibe code with a moat of 5/10, so an AI-assisted MVP takes about 2 weeks and a full replacement about Never (Requires global tax entities, banking rails, legal indemnification).
Which one costs less, FastSpring or Rally?
FastSpring at $750/mo/mo for a typical mid-market store. The gap between the two is about usage-based a year.
What do I lose if I replace FastSpring?
Merchant of Record legal status and cross-border indirect tax liability assumption Automated VAT/GST calculation, collection, and filing across 200+ global jurisdictions Global payment gateway routing, localized payment methods (iDEAL, Pix, Alipay), and acquirer optimization
What do I lose if I replace Rally?
Out-of-the-box PCI-DSS compliance isolation for payment processing Native post-purchase authorization holding and order modification logic Pre-integrated connections to tax engines (Avalara/TaxJar) and shipping rate APIs
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