blkbx — checkout without the cart

blkbx was a commerce platform for buying a product directly from a social post, ad, email or QR code. Buyers used a single-page checkout with Apple Pay, Google Pay or card payment, without a cart or account step.

My role and collaborators

As co-founder and CTO, I focused on checkout, seller onboarding, attribution and distribution. Apptension was the software partner; its SaaS Boilerplate supplied authentication, authorization, payments, email and server infrastructure.

Two blkbx mobile checkout screens with Apple Pay and social links — Product screens from Apptension’s public case study: single-product checkout with wallet payment.

Payments and orders

Stripe Connect handled seller accounts and payouts. Payment webhooks updated an order state machine in PostgreSQL and triggered inventory, fulfillment and branded email workflows.

Seller tools and attribution

The dashboard combined product variants, inventory, pricing, branded checkout settings and campaign assets. Per-product creative and per-channel links tracked views, taps, checkout and payment, giving sellers a view of the purchase funnel.

Architecture

The two views show the purchase and order flow, and the seller setup and distribution flow.

The purchase path is short. Payment events update order state and trigger downstream work after checkout.

01
Product link Branded checkout
purchase intent
02
Branded checkout Node API
order input
03
Node API Stripe Connect
payment request
04
Stripe Connect Webhook handling
payment events · asynchronous / scheduled
05
Webhook handling PostgreSQL
state updates · asynchronous / scheduled
06
Webhook handling Amazon SES
notifications · asynchronous / scheduled

Product link · Social, ad, email or QR

A channel-specific link brings purchase intent into checkout.

Branded checkout · One page / wallet first

A single-product checkout offers Apple Pay, Google Pay and card payment.

Node API · Order shaping

The application prepares the order and payment request.

Stripe Connect · Payment + seller payouts

Stripe handles the payment and connected-account payout layer.

Webhook handling · Payment event processing

Payment events drive the application’s order state machine.

PostgreSQL · Orders / refunds / fulfillment

Persistent order state supports orders, refunds and fulfillment after checkout.

Amazon SES · Branded transactional email

Receipts and shipping messages are part of the post-payment workflow.

Design decision

Separate checkout from payment confirmation. Webhook-driven state handles work that continues after the buyer leaves the page.

Conceptual architecture. Explore component details in the diagram or the connection list.

Product scope

The initial checkout expanded into seller onboarding, catalog management and order operations. Attribution became part of the platform because sellers also needed to understand how buyers reached checkout.