PayStream
A payment orchestration layer that doesn't require a dedicated integration team to operate
2024
FinTech
Time-to-first-transaction for new clients down from 6 weeks to 9 days
The problem
PayStream's clients are e-commerce businesses and SaaS companies operating across multiple European markets. The problem wasn't that their clients couldn't accept payments — it's that each payment method or market expansion required a new integration project, typically 4–6 weeks of engineering time. One client had four engineers maintaining payment integrations full-time. Under PSD2, the compliance surface had also expanded significantly: Strong Customer Authentication rules varied by transaction value and merchant category code, and most clients were handling this inconsistently, creating both friction and regulatory exposure. PayStream had attempted to solve this with a webhook-based API they'd built in-house in 2021, but the documentation was incomplete, error messages were opaque, and the client success team was spending most of their time debugging integration issues rather than selling.
Our approach
We approached this as a developer experience problem as much as an infrastructure one. The first phase was a complete API redesign — idempotent requests throughout, standardised error codes mapped to plain-language descriptions, and a test environment that simulates real-world edge cases including network timeouts and partial settlement failures. The routing engine evaluates payment method, currency, amount, and merchant category at transaction time to apply the correct SCA exemption logic automatically. Reconciliation exports were standardised into a format compatible with the four accounting platforms most common among PayStream's client base, eliminating the custom ETL work clients had been doing manually. We introduced a no-code integration path for clients on Shopify and WooCommerce that goes live in under two hours; the full API integration path now averages nine days including compliance review.
The results
Time-to-first-transaction for new clients dropped from six weeks to nine days. The client success team's inbound support tickets related to integration issues fell 64% in the three months after launch. PayStream onboarded 34 new clients in the following quarter — their highest ever. The SCA exemption logic has a 94% automated decision rate; 6% of transactions are flagged for manual review due to edge cases in merchant category classification, which is an ongoing calibration effort. One thing we'd do differently: the no-code Shopify integration launched two months after the API because we underestimated the edge cases in Shopify's webhook reliability — worth building earlier next time.
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