Backend API Integration Engineer (CRM & Financial Systems)

Overview
We are seeking an experienced Backend API Integration Engineer to design and build a secure middleware service that connects a CRM platform (GoHighLevel) with a third-party enterprise financial software system. This role focuses on building reliable, compliant, return-level data integrations that support automation, workflow triggers, and operational visibility within the CRM.
This is not a no-code or funnel-builder role. The ideal candidate has strong experience with REST APIs, token-based authentication, and handling sensitive financial data.

Responsibilities
Design and build a secure backend middleware service to integrate GoHighLevel with a third-party enterprise financial platform
Implement token-based authentication and session handling
Develop two-way data synchronization between systems (read and controlled write-back)
Map external system records to CRM contacts and opportunities
Update CRM custom fields, tags, notes, and pipeline stages based on external system events
Implement status-driven automation triggers within the CRM
Build robust logging, error handling, retry logic, and audit trails
Deploy, document, and support the integration in a production environment

Technical Requirements
Strong experience building RESTful API integrations
Experience with token-based authentication (OAuth-style flows)
Proficiency in backend development (Node.js or Python preferred)
Experience working with OpenAPI / Swagger specifications
Familiarity with GoHighLevel’s API (contacts, opportunities, custom fields, workflows)
Secure handling of sensitive financial or regulated data
Experience deploying and maintaining backend services (AWS, GCP, Azure, or similar)

Preferred Qualifications
Experience with financial, accounting, or compliance-sensitive systems
Experience designing middleware or integration platforms
Knowledge of idempotency, rate limiting, and duplicate-event prevention
Experience creating system logs and audit trails for regulated data
Ability to provide clear technical documentation and handoff
Deliverables
Fully functional backend integration service
Secure credential handling and deployment setup
CRM data mapping and automation logic
Logging and error-monitoring framework
Technical documentation and handoff support
Engagement Details
Contract or project-based engagement
Opportunity for ongoing maintenance and feature expansion
Remote work acceptable

Screening Questions
Describe a backend API integration you’ve built involving financial or sensitive data
How do you typically handle token-based authentication and credential security?
How do you prevent duplicate or out-of-order updates in integrations?
What is your preferred hosting stack for middleware services and why?
Have you worked with GoHighLevel’s API? If so, please describe