Building a Fintech Product on Equinox: A Developer's Guide

A practical look at how developers and product teams integrate with Equinox to build compliant financial products. From API setup to production launch.

Equinox is a platform, not a product. That distinction matters for anyone building on top of it. The goal of this guide is to give developers and product managers a clear picture of how Equinox is structured, how integration works in practice, and what to expect at each stage — from API credentials to production launch.

Architecture Overview

Equinox follows a modular API architecture. Each financial product — EWA, BNPL, invoice management, lending, insurance — is exposed as a distinct API domain with its own resource endpoints. These domains share common infrastructure: authentication, KYC, webhook event delivery, and the compliance layer. You interact with each module independently, but they share the same credential context and configuration environment.

All API communication uses HTTPS with JSON request and response bodies. The base URL structure separates environments cleanly: a staging base URL for development and testing, and a production base URL for live traffic. Nematix provides both when you are onboarded.

Equinox does not impose a single integration pattern. Some integrations are server-to-server: your backend calls the Equinox API directly, processes the response, and surfaces results through your own UI. Others use Equinox’s embedded components — pre-built UI widgets you drop into your web or mobile interface, backed by the same API. You can mix both within a single integration.

Authentication and Onboarding

Equinox uses API key authentication. Your account is provisioned with a pair of keys: a publishable key for client-side contexts (initialising embedded widgets, reading non-sensitive configuration) and a secret key for server-side calls (creating transactions, accessing customer data, triggering disbursements).

Never expose your secret key in client-side code. All calls that create or modify financial records — initiating an EWA withdrawal, confirming a BNPL transaction, creating an invoice — must be made from your server.

Webhook setup is completed during onboarding. You register one or more endpoint URLs in the Equinox dashboard. Equinox delivers signed POST requests to those endpoints when significant events occur: a withdrawal is confirmed, an instalment is collected, an invoice is viewed or paid. Each webhook payload includes a signature header that you verify against your webhook secret before processing the event. This is how you keep your system’s state synchronised with Equinox without polling.

The onboarding process also includes configuring your module parameters: withdrawal limits for EWA, instalment structures for BNPL, invoice templates, and so on. These are set in the Equinox dashboard and do not require API calls to configure — they define the behaviour of your API interactions.

Integrating the EWA Module

The EWA integration has three logical components: payroll data connection, balance calculation, and withdrawal trigger.

Payroll data connection. Equinox needs to know how much a given employee has earned to date in the current pay cycle. You push this data to Equinox via the payroll sync endpoint, typically on a daily schedule or triggered by a shift completion event. The payload includes the employee identifier (matched against the enrolled employee record), the pay period dates, and the accrued earnings figure. Equinox does not need access to your payroll system directly — it consumes whatever data you push.

Balance calculation. Once payroll data is synced, Equinox calculates the available withdrawal balance for each employee: a configured percentage of accrued earnings (typically 50% to 80%, set in your platform configuration) minus any amounts already withdrawn in the current cycle. Employees see this available balance in your app or the Equinox embedded widget.

Withdrawal trigger. When an employee requests a withdrawal, your app calls the Equinox EWA disbursement endpoint with the employee ID and requested amount. Equinox validates the request against the available balance and the withdrawal limits in your configuration, then triggers the disbursement to the employee’s registered bank account or e-wallet. The response includes a transaction ID and a status. Subsequent status updates are delivered via webhook as the disbursement progresses through the payment rail.

On payday, you notify Equinox of the payroll run via the payroll completion endpoint. Equinox calculates the total amounts to recover across all employees who made withdrawals in the cycle and provides you with a recovery schedule. The net payroll disbursement — wages minus withdrawals — goes to each employee as normal.

Integrating the BNPL Module

The BNPL integration centres on three moments: eligibility check, transaction initiation, and merchant callback.

Product catalogue. For BNPL to work at checkout, Equinox needs to understand what is being purchased. You pass the cart contents — item descriptions, amounts, merchant identifier — as part of the transaction initiation call. No separate product catalogue registration is required for standard B2C flows.

Credit check handoff. When a customer selects BNPL at checkout, your frontend initiates the Equinox BNPL flow — either via API call to your backend, which calls Equinox, or by initialising the Equinox embedded widget. Equinox presents the application form to the customer, collects the required data, runs the decisioning logic, and returns an approval or decline. The decisioning result is delivered to your backend via webhook and as a redirect to your specified return URL.

Merchant callback. Once a BNPL transaction is confirmed, Equinox delivers a webhook event to your registered endpoint with the transaction details: amount, instalment schedule, expected settlement date. Use this event to update your order management system and fulfil the order. Do not fulfil the order before receiving the confirmation webhook — treat the BNPL decision as a payment authorisation, not an intent.

Settlement is handled automatically by Equinox on your configured schedule. You do not need to initiate settlement requests.

White-Label Branding

Every customer-facing surface in Equinox supports white-label configuration. This includes the embedded widgets, email notification templates, the client-facing invoice portal, and the customer app (where applicable).

Branding configuration is managed in the Equinox dashboard under your platform settings. You upload your logo, define your primary and secondary colour palette in hex, and specify your brand font if you are using the embedded widget components. Changes to branding configuration take effect immediately in staging and on your next deployment trigger in production.

For deeper UI customisation — custom layouts, non-standard component structures — Equinox supports a CSS override layer on embedded components. You provide a stylesheet URL; Equinox loads it within the widget context. This approach covers the majority of branding requirements without requiring a fully custom frontend build.

Custom domain configuration is available for the client-facing portal surfaces. Your invoice portal can be served from invoices.yourdomain.com rather than an Equinox subdomain. DNS configuration is straightforward: a CNAME record pointed at the Equinox portal infrastructure, verified in the dashboard.

Compliance by Default

Equinox’s compliance components are embedded in every API call that involves a customer. You do not need to integrate KYC separately. When a customer onboards to your EWA or BNPL product, the Equinox onboarding flow includes identity verification steps. The KYC status of each customer is tracked in Equinox and checked automatically before any financial transaction is permitted.

AML screening runs at the point of customer onboarding and is re-triggered by configurable events (high-value transactions, account changes). Results are surfaced via webhook if manual review is required; otherwise the flow continues without interruption.

BNM reporting hooks are built into the transaction infrastructure. Equinox maintains the transaction records and aggregated reporting data required for regulatory reporting. If your platform is subject to direct BNM reporting obligations, Nematix’s compliance team can advise on the applicable reporting format and how Equinox’s data exports map to it.

For the LHDN e-invoicing mandate, the Invoice Module handles submission to MyInvois as part of the standard invoice creation flow. No separate integration with the MyInvois API is required from your side.

Testing and Staging Environments

Equinox provides a full staging environment that mirrors production behaviour without processing real transactions. Your staging API keys are distinct from production keys and are provisioned during onboarding.

The staging environment includes test employee records for EWA flows, test customer profiles for BNPL decisioning, and a simulated payment rail for disbursement and collection testing. Webhook delivery operates in staging the same way as production — your registered staging endpoint will receive events as transactions move through test states.

Use the staging environment to validate the complete end-to-end flow — including webhook receipt, signature verification, and your downstream order or payroll system updates — before moving to production. Nematix’s technical onboarding team can walk you through the recommended test scenarios for each module.

Common Gotchas

Webhook ordering is not guaranteed. If multiple events occur in rapid succession — a BNPL transaction confirmed, then immediately a partial refund — webhooks may arrive out of order. Design your event handling to be idempotent and to re-fetch resource state from the API if event ordering matters for your logic.

Available balance is point-in-time. The EWA available balance returned by the API reflects the balance at the moment of the call, based on the most recent payroll sync data you pushed. If your payroll data is stale, the balance will be stale. Implement a reliable daily sync schedule and handle the edge case where a withdrawal request arrives before that day’s sync has been processed.

Staging credit decisions are configurable. By default, the staging environment approves all BNPL applications to simplify testing. If you need to test decline flows, contact Nematix support to configure a test customer profile that triggers a decline decision.

White-label domain propagation takes time. After configuring a custom domain for the client portal, allow up to 24 hours for DNS propagation. Do not switch production traffic to the custom domain until you have verified it resolves correctly in staging.

Getting Support from Nematix’s Technical Team

Nematix provides technical onboarding support for all Equinox integrations. The onboarding process includes an initial architecture review call, access to the API reference documentation and Postman collection, and a dedicated Slack or Teams channel for integration questions during your build phase.

For production issues, Nematix maintains a technical support channel with defined response SLAs. Webhook delivery failures, payment rail delays, and compliance query resolution are handled by the Nematix technical and compliance teams — not routed to a generic support queue.

If your integration involves a non-standard use case — a module configuration not covered in the standard documentation, a regulated activity that requires Nematix compliance sign-off before activation, or a bespoke reporting requirement — raise it during the architecture review call rather than discovering it mid-integration.

Related Reading

• What is Equinox? Nematix’s Modular Fintech Platform Explained — The product overview before you start the technical integration.
• Equinox Invoice Module: Simplifying Financial Operations for SMEs — Details on the Invoice Module you’ll integrate with LHDN compliance built in.
• Malaysia E-Invoicing Mandate: What Every Business Needs to Know — The LHDN compliance context behind the e-invoicing hooks in the Equinox platform.

Explore Equinox — Nematix’s modular fintech platform for building and launching financial products at speed.