Introduction

Lynx provides APIs for building healthcare-fintech products and workflows, including member enrollment, client onboarding, accounts, cards, contributions, reimbursements, transactions, and e-commerce-enabled purchasing.

Before integrating, every technical team should understand four things:

• How Lynx is structured
• Which integration path applies to their use case
• How to authenticate and work in Sandbox
• How to complete one successful workflow end to end

Sandbox Setup

The Sandbox environment lets you integrate and test without affecting real accounts or card networks.

What Lynx Pre-Configures in Sandbox

When you receive Sandbox access, Lynx provisions a test Client Org with:

• Sample products (HSA, FSA, OTC, etc. depending on your use case)
• A default card package (generic test design)
• Simulated KYC (use specific test SSNs to trigger pass/fail/document-required scenarios)
• Simulated funding (no real ACH or bank connections)

This lets you start calling APIs immediately. In Production, all of these are configured to your specifications during implementation.

Getting Sandbox Access

• Contact your Client Success Manager to request Sandbox credentials
• You will receive:
  • Login credentials for the Client Dashboard
  • Your clientOrgName
  • An API Bearer Token / Instructions to generate one

Generating an API Token

• Log into the Client Dashboard at Lynx Client Dashboard
• Navigate to API Keys (under Settings or Developer section)
• Generate a new token or copy your existing token
• Store it securely — treat it like a password

Making Your First Authenticated API Call

All Lynx API calls require a Bearer Token in the Authorization header:

curl -X GET "https://sandbox.lynx-fh.co/api/v1/clientorg/{clientOrgName}/plan/summary" \
  -H "Authorization: Bearer {your_api_token}" \
  -H "Content-Type: application/json"

This returns the plans and card packages available to your Client Org — values you'll need for member enrollment.

Configuring Webhooks

Lynx sends asynchronous status updates via webhooks. To receive them:

• In the Client Dashboard, navigate to Webhooks
• Register your endpoint URL (must be HTTPS)
• Subscribe to the events you need:
  • (see Events documentation for full list)

In Sandbox, you can use a tool like webhook.site or ngrok to inspect incoming payloads.