Backend Developer & API Integrations

We are seeking an experienced Backend & API Integrations Developer for a specialist project engagement focused on Semble, Payments, and Healthcare Website Integrations. This role is based in Dubai, UAE, and requires collaboration with a Lead Frontend Developer on a six-week website rebuild for CP Medical Clinic, a CQC-regulated private medical clinic in Chelsea, London.

Contract: Specialist project engagement, late August to October 10, 2026
Fee: AED 4,500 fixed project fee
Working Model: Part-time possible, with mandatory availability at key integration stages.

About the Project

This is a specialist backend engagement, not a full-time website development role. Key responsibilities include Semble integration, payment infrastructure, secure server-side functionality, domain and email protection during migration, and production integration support.

Required Qualifications

Please do not apply unless you meet these requirements:

• You are currently based in Dubai and can attend face-to-face technical sessions.
• You have at least 5 years of professional software or web-development experience.
• You have personally implemented genuine third-party API integrations in production. (Installing plugins, widgets, or embeds does not count.)
• You have hands-on experience with backend frameworks such as Node.js/Express/NestJS, PHP/Laravel, Python/FastAPI or equivalent, along with authentication, webhooks, databases, error handling, Git, and staging/production environments.
• Semble's API is GraphQL, and GraphQL experience is important for this role. While a strong engineer can pick it up, please state your GraphQL experience honestly.
• You will personally perform the work. A frontend developer whose API experience consists mainly of consuming endpoints built by someone else is not suitable. Agencies and subcontracted development teams will not be considered.

The Two-Developer Structure

This project involves two named developers working directly together: a Lead Frontend Website Developer and you. Both report directly to CPMC, work in the same CPMC-owned repository and staging environment, and may not pass work to third parties. You must be comfortable agreeing interfaces with another developer and documenting handovers.

Semble Integration

CPMC utilizes Semble as its practice-management and booking platform. You are not building an appointment booking system from scratch. The required architecture is broadly:

CPMC website → secure backend integration → Semble → retrieve live availability → patient selects appointment → booking submitted to Semble → confirmation or error returned to the website

Your responsibilities include reviewing Semble API capabilities and account permissions, authentication, availability retrieval, booking submission, validation, error and empty states, duplicate-request protection, secure credential handling, logging, staging configuration, and production support.

Week 1: Technical Gate

During Week 1, you must establish the technical viability of the required Semble workflow, demonstrate a working authenticated proof-of-concept, and document available operations, restrictions, and dependencies. You are not financially penalized for discovering a genuine Semble limitation. If technical validation shows the workflow cannot be delivered safely within the timetable, the project will redirect the booking journey to a secure enquiry route while you continue with payment and other integration work. The fee remains unaffected. An early, well-evidenced negative finding is more valuable than an optimistic integration that fails near launch.

Week 2: API Contract and Mock Service

By the end of Week 2, provide the Lead Frontend Developer with a documented endpoint contract and a runnable mock service, defining website-facing endpoints, requests, representative responses, error conditions, and empty states. The frontend developer will build against this contract while you complete the live integration. The production implementation will then be substituted behind the same agreed interface without requiring frontend rebuilding.

Payments and Klarna

Two clinic services are sold online (£745 and £1,995), with Klarna offered for both. The £1,995 service must support a possible £600 partial refund after a completed purchase.

You own the entire payment layer, including: payment-provider integration, checkout and payment-session creation, server-side credential handling, webhooks and verification, transaction-state management, idempotency and duplicate-request protection, refund and partial-refund functionality, backend validation, error handling, and testing.

The Lead Frontend Developer owns the visible checkout journey and interface. Klarna has regulatory requirements; mandatory consumer-credit wording must appear adjacent to the Klarna mark, implemented so the mark and wording cannot be separated by content edits.

DNS and Clinic Email Protection

You are responsible for the technical protection of the existing live domain during deployment. The clinic's email, operating on the same domain, must not be disrupted.

You must document the existing DNS configuration in full (including A, AAAA, CNAME, MX, SPF, DKIM, DMARC, and verification records) before any changes. Preserve email-related records through migration and produce a documented rollback plan before production cutover. DNS configuration must be documented in Week 1, not at cutover. Applicants with personal experience in live-domain migrations are strongly preferred.

Security and Healthcare Environment

This is a healthcare website. API credentials must remain server-side and never appear in client code or the repository. Implementation must follow appropriate data-minimisation, secure-transmission, access-control, logging, and error-handling principles. You should be comfortable working in a UK GDPR-sensitive environment and documenting the system for future maintenance. Clinical wording and workflows are supplied by CPMC and must not be independently altered.

Employment Status and Availability

Unlike the Lead Frontend role, you do not need to be free for six weeks. We will consider candidates who hold another professional role, provided you can guarantee the necessary project time, attend required Dubai sessions, respond promptly during integration periods, and are legally permitted to undertake the engagement. We prefer honest part-time delivery over claims of full-time availability that the workload does not require. You must be substantially available during Week 1, integration testing, pre-launch QA, and production deployment. Unpredictable late-night or occasional weekend availability is not suitable.

Milestones

• Kickoff (late August): Face-to-face technical session in Dubai with the Lead Frontend Developer. Existing DNS configuration documented.
• End of Week 1: Semble authenticated connection and feasibility demonstrated; available operations and limitations documented.
• End of Week 2: Documented API contract and runnable mock supplied to the Frontend Developer.
• End of Week 4: Semble booking and payment flows operating end-to-end on staging, including failure paths.
• End of Week 5: Production configuration, security, DNS and email migration plan, payment and refund testing, documentation complete.
• Week 6: Production launch support and final handover.

Project Controls

• Work in the same CPMC-owned Git repository and staging environment as the Lead Frontend Developer, following agreed branch and pull-request processes.
• No development may live exclusively on your own private hosting.
• Credentials must never be committed to Git.
• No subcontracting without prior written CPMC approval.
• Document the integration, environment requirements, external dependencies, configuration, and known limitations.
• 10-working-day post-launch defect warranty on delivered functionality.

Fee

AED 4,500 fixed project fee, paid against the technical milestones above.

Pay: AED 4,000.00 per month

Application Question(s)

• Are you currently based in Dubai and able to attend mandatory face-to-face technical sessions? PLEASE DO NOT APPLY IF YOU ARE NOT!
• Do you have at least five years of professional software or web-development experience?
• Have you personally implemented a genuine third-party REST or GraphQL integration in a production system?
• Have you personally implemented payments, webhooks, or another transactional integration where retries, duplicates, and failure states had to be handled correctly?
• Can you guarantee sufficient availability between late August and October 10 to meet the stated milestones?
• Will you personally perform the work, without subcontracting or outsourcing?

Work Location: Hybrid remote in Dubai (Dubai)