Item: ClickMasters Software Development Company
Rating: 5
Author: ClickMasters Case Study Team

Project Overview

Legacy COBOL to Cloud Migration — UK Insurance Company. A mid-size UK insurance company had a 25-year-old COBOL-based policy management system processing 40,000 policies daily....

Technology Stack

PythonFastAPIPostgreSQLAWS eu-west-2TerraformGitHub ActionsDjango Admin for operations team

The Challenge

A mid-size UK insurance company had a 25-year-old COBOL-based policy management system processing 40,000 policies daily. The system was unmaintainable — developers with COBOL knowledge were retiring, and the system could not support modern APIs required for FCA Consumer Duty compliance (transparent pricing display, automated renewal communications). The business needed to modernise without a "big bang" rebuild that could cause service disruption.

Our Approach

Strangler Fig Migration: Built a new Python/FastAPI backend incrementally. Installed a proxy layer (AWS API Gateway) in front of the legacy system routing new requests to the new services while legacy requests continued to pass through. Migrated one module at a time over 12 months. Business Logic Extraction: Reverse-engineered COBOL business logic (rate tables, underwriting rules) using the strangler fig approach. Documented all rules in Python with 100% test coverage. Legacy and new system ran in parallel for 6 months — results compared daily. FCA Consumer Duty Enablement: New system exposed REST APIs enabling the consumer-facing web portal to display transparent pricing (previously impossible from COBOL). Automated renewal communications with correct FCA-required price increase notifications. UK GDPR Migration: Migrated 40,000 policyholder records with full GDPR compliance. Data quality cleansing (removing duplicate records). Retention policy enforcement (policies over 7 years purged per regulatory requirements). All migration activities documented for ICO accountability.

The Results

Legacy COBOL system fully decommissioned after 14 months. 100% policy continuity — zero service disruption. New system processes 40,000 policies daily on AWS eu-west-2. Developer team of 4 now maintaining a modern Python codebase. FCA Consumer Duty compliance enabled. Solvency II Pillar 3 reporting now automated.

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Client Testimonial

“The strangler fig approach meant we had zero disruption to our policyholders throughout the migration. ClickMasters' understanding of insurance data and FCA requirements meant the new system was compliant from day one — not a retrofit." — CTO, UK Insurance Company (name withheld)”

ClickMasters Case Study Team

Reviewed by James Whitmore, CTO