Implementation Engineer

Flex is a company focused on merchant onboarding and technical integrations. They are seeking a Contract Implementation Engineer to support partners in implementing and launching their APIs and checkout flows, while troubleshooting integration issues and collaborating with various teams.

Responsibilities:

• Support merchants during onboarding and implementation of our Shopify Payment Method solutions
• Provide guidance on basic Shopify Marketing Best Practices which include building an HSA/FSA landing page, adding Flex badges to the PDP, and targeted email marketing
• Troubleshoot and debug any implementation and post-implementation issues related to both Flex Shopify Payments and Marketing App
• Lead post implementation feature enable for Shopify features (e.g. Subscription Support, Passing telehealth consultation costs to customers)
• Partner closely with Support Engineering, Product, and Engineering to escalate bugs and unblock launches
• Help document common implementation patterns, FAQs, and known issues
• Occasionally assist with light data validation or configuration updates in internal tools

Requirements:

• 2+ years of experience in an implementation, support engineering or customer engineering
• Comfortable working with REST APIs, JSON, and HTTP requests
• Experience using Postman (or similar tools) to test and debug APIs
• Familiarity with webhooks and asynchronous event flows
• Strong troubleshooting and problem-solving skills
• Clear, empathetic written communication — you'll be working directly with external partners
• Ability to work independently, prioritize tasks, and manage multiple implementations at once
• Experience supporting payment systems, subscriptions, or checkout flows
• Familiarity with Stripe, Shopify, or other e-commerce platforms
• Experience in a startup or high-growth environment
• Light SQL or data-debugging experience
• Previous experience working with customer-facing technical roles