Backend API Developer for Claims Engine

Automated Claims Processing Engine (Backend API) Category: Backend Development / API Engineering Budget: £1,350 GBP Hourly rate range (if hourly bids considered): $30/hr – $250/hr Project deadline: Saturday, 10 October 2026 Description: We're building a backend engine that ingests structured claim files, validates them against business rules, and outputs adjudication results via API. This is a pure data-processing/backend service — no UI work involved. Looking for someone who can design the validation pipeline, build the API layer, and ensure the engine handles edge cases and malformed input gracefully. Key requirements: Strong backend/API development skills (Python, Java, or C#) Experience with rules-engine or workflow-validation logic Comfortable working with structured file formats (CSV, XML, or EDI-style files) Solid testing discipline for data-processing pipelines Deliverables: Working API endpoint(s) for claim submission and status retrieval Validation/rules engine with documented rule set Test suite covering standard and edge-case inputs Money-Back Guarantee & Acceptance Terms: Freelancer's acceptance of these terms. By commencing any work under this project — including, without limitation, accepting the award, confirming a start date, or performing any preparatory or substantive task — the Freelancer is deemed to have read, understood, and irrevocably accepted all terms of this posting in full, including this Money-Back Guarantee & Acceptance Terms clause. Commencement of work by the Freelancer constitutes their binding acceptance of the contract; it is not conditional on any further signature or confirmation. Milestone release ≠ Client's acceptance of the work. Release of any milestone payment by the Client authorises the Freelancer to commence or continue work only. It does not constitute the Client's acceptance of that work or of the final deliverable. The Client's acceptance of the deliverable occurs solely upon the Client's written confirmation that it conforms to the specification set out in this posting. Time is of the essence. The Project Deadline stated above (10 October 2026) is a material term of this engagement. Money-back guarantee. If the completed deliverable(s) are not delivered in full working order by the Project Deadline, and the Client has not granted an express written extension prior to that deadline, this contract shall automatically and immediately terminate (become void) without further notice, and the Freelancer shall refund the Client all sums paid under this contract in full within 5 business days of the deadline lapsing. Extensions. Any extension to the Project Deadline is valid only if agreed in writing (including via the platform's messaging system) by the Client before the original deadline expires. No extension is implied by silence, delay in response, or continued work after the deadline has passed. No waiver. The Client's acceptance of late or partial work, at its sole discretion, does not waive the Client's rights under this clause in respect of any other milestone or deliverable. Survival. This clause survives termination of the contract.