Krepling · Payments Research · July 2026 Access Invite-Only

Adding Krepling Pay as a Shopify Payment Method

Integration path, checkout position, technical requirements, and fee implications

Verdict
Feasibility
Viable — but gated
The integration path exists. Getting API access is a 3–12 month invitation process.
Checkout Position
Below Shop Pay, not replacing it
The express checkout row is locked to Shopify's own partners. Krepling Pay appears in the payment methods list alongside credit cards and BNPL.
TSYS Architecture
Unchanged
The processing layer stays identical. Only the entry/exit flow changes: redirect in, GraphQL resolve out.
Checkout Position
Express Row — Locked to Shopify partners Locked
Shop Pay Apple Pay Google Pay PayPal (legacy) Amazon Pay
Payment Methods List — Krepling Pay appears here Viable
Credit / Debit Card Klarna Afterpay Krepling Pay
Why the Express Row Is Off-Limits
The express checkout row is reserved for Shopify's own first-party relationships. PayPal occupies it only because of a legacy pre-API partnership — that arrangement cannot be replicated. No payment app built through the Payments Apps API can enter this row. Krepling Pay will always appear in the payment methods list below, in the same position as Klarna and Afterpay.
Getting API Access
The Fundamental Gate
The Payments Apps API is invitation-only — no public application form
This is the only viable path for native Shopify checkout integration. Access is granted by invitation. There is no open application form. The process is: open a Shopify Partner Support chat explicitly requesting Payments Apps API access, and run a parallel conversation through Shopify Sales. Build time once access is granted is 4–6 weeks. Waiting for the invite is the 3–12 month variable.
Step 1
Contact Shopify Partner Support + Sales in parallel
Open a Partner Support chat requesting Payments Apps API access. Simultaneously engage Shopify Sales to run a second track. Having both touchpoints active shortens the queue.
Start immediately
Step 2
Invitation received — Payments Apps API unlocked
Shopify grants access to the Payments Apps API and `write_payment_sessions` OAuth scope. You can now build against the sandbox environment.
3–12 months from contact
Step 3
Build the integration
Implement the offsite redirect extension, `paymentsAppConfigure`, session resolve/reject mutations, refund handlers, and test mode. mTLS, 99.95% uptime, PCI-DSS required.
4–6 weeks build
Step 4
Submit for Shopify review & publish
Shopify reviews the payment app. After approval, the app is published. It will not appear in the browseable list until 50 merchant installs and $1M processed — early merchants need a direct install URL.
2–4 weeks review
Step 5
Discovery threshold: 50 installs + $1M processed
Only after crossing this bar does Krepling Pay appear organically in Shopify Admin under "Additional payment methods." Plan a direct merchant acquisition strategy for the early phase.
Depends on merchant growth
Technical Architecture
What Changes
The entry and exit wrapper around TSYS
  • Shopify POSTs to your payment_session_url with session data
  • You return a redirect_url — customer leaves Shopify domain to Krepling's hosted page
  • After TSYS responds, call paymentSessionResolve or paymentSessionReject via GraphQL
  • Shopify returns a redirect URL in the mutation response — you send the customer back
  • This is a full-page redirect, not an iframe — Shopify does not allow iframes here
What Stays the Same
The entire TSYS processing layer
  • TSYS MultiPASS authorization — unchanged
  • Tokenization & tsys_card_transaction_id — unchanged
  • krepling-gateway Django/Gunicorn on EC2 — unchanged
  • CVV handling, PCI scope, log masking — unchanged
  • The hosted page the customer lands on is Krepling's own — same as WooCommerce flow
Technical Requirements
API endpoint
{shop}/payments_apps/api/2026-07/graphql.json
OAuth scope
write_payment_sessions
Extension type
Offsite payment (full-page redirect — not App Bridge, not embedded)
Core mutations
paymentsAppConfigure
paymentSessionResolve
paymentSessionReject
refundSessionResolve
refundSessionReject
Security
mTLS required (mutual TLS — not just standard TLS). PCI-DSS compliance required.
Uptime SLA
99.95% uptime requirement. Session handlers must be idempotent.
App type
embedded: false — standalone app, not App Bridge
Test mode
Required during development. Shopify sends test flag; app must handle without real TSYS calls.
The Fee Problem
Shopify Charges an Extra Transaction Fee for All Non-Shopify-Payments Providers
Merchants using any third-party payment provider — including Krepling Pay — pay Shopify an additional fee per transaction on top of Krepling's own rate. This is a structural disadvantage. Shopify Payments avoids this entirely. Target Advanced and Plus merchants where the adder is tolerable.
Shopify Plan Extra Fee (Shopify) Monthly Cost Competitive Position
Basic +2.0% per transaction $39/mo Difficult — makes Krepling materially more expensive
Shopify +1.0% per transaction $105/mo Tolerable if Krepling rate advantage offsets it
Advanced +0.6% per transaction $399/mo Target tier — fee impact manageable
Plus +0.2% per transaction $2,300+/mo Primary target — fee nearly negligible
Two Separate Apps
Shopify treats catalog/order access and payment processing as entirely separate app categories with separate review tracks. Krepling Pay and the Kora voice app cannot be the same Shopify app.
Kora App Faster path
Catalog read + Order management
  • Registers store with Krepling backend
  • Reads products.json for Kora AI voice calls
  • Creates checkout URLs, sends via SMS/email
  • Standard Shopify app review — no invite needed
  • Lays groundwork for Agentic Checkout (Phase 2)
vs
Krepling Pay App Invite required
Native checkout payment method
  • Appears in Payment Methods list at checkout
  • Full-page redirect to Krepling's hosted page
  • Requires Payments Apps API invitation (3–12 mo)
  • mTLS, 99.95% uptime, PCI-DSS bar
  • Extra Shopify transaction fee for merchants
Recommended Path
Parallel Track Strategy
Ship Kora now. Start the Krepling Pay invite queue today.
The two tracks are independent. Kora can ship and generate real merchant installs while the Payments Apps API invite is pending — those installs become the install base that helps demonstrate traction to Shopify during the Krepling Pay review.
1
Today — open the Payments Apps API invite request
File via Partner Support chat + Shopify Sales contact. The invite queue is the long pole; starting now compresses the total timeline. Mention Krepling's existing WooCommerce payment processing volume as proof of capability.
2
Next 4–6 weeks — ship the Kora Shopify app
Catalog read + order management scope + Twilio phone call + SMS/email checkout URL. This is the faster approval path and begins building the merchant install base Krepling Pay will need.
3
Once invite arrives — build Krepling Pay integration
4–6 weeks build: offsite redirect extension, paymentSession mutations, mTLS setup, refund handlers, test mode. Deploy on krepling-gateway infrastructure with 99.95% uptime monitoring.
4
Target Advanced & Plus merchants first
The extra Shopify transaction fee (+0.6% / +0.2%) is tolerable at higher plan tiers. Basic merchants face +2% which is a hard sell unless Krepling's base rate is significantly lower than Shopify Payments. Direct install URL campaigns until the 50-install / $1M discovery threshold is crossed.
5
Phase 2 — Kora Agentic Checkout closes the loop
Order management permission (from the Kora app) + Krepling Pay (from the payment app) together enable Kora to complete a full purchase by voice — no redirect, no link. The customer calls, Kora charges their saved Krepling Pay method, merchant gets a confirmed order.