RPG Developer - IBM i / AS400 Core Systems

We are recruiting an RPG Developer to join an organisation in the retail distribution and fulfilment sector. This is a high-volume operation where the IBM i (AS400) platform runs the engines behind order management, warehouse execution, inventory accuracy, pricing, and customer billing.

The environment is mature, stable, and heavily relied upon - but it's not standing still. The business is investing in pragmatic modernisation: increasing automation, improving integration capability, tightening testing and release discipline, and upgrading codebases toward RPG ILE and free-format RPG.

If you enjoy working on mission-critical systems where your code directly impacts real-world operations (and you want to modernise without breaking what works), this is a strong long-term role.

What you'll be doing

You'll be hands-on across development, support and continuous improvement, working closely with business stakeholders and technical peers., * Develop, enhance and maintain applications on IBM i using RPG (ILE / free-format), ensuring clean structure, reusability and robust error handling.

• Work with DB2 for i to design and optimise data access (SQL tuning, indexing, query plans, commitment control).
• Support and improve IBM i batch and online processes underpinning operational workflows (orders, inventory, picking, dispatch, invoicing).
• Troubleshoot production issues: job logs, message queues, spool files, locking/contention, data integrity defects-driving root cause fixes.
• Build and maintain integrations: APIs and services where applicable, plus file-based and partner interfaces (EDI/XML/flat-files/SFTP).
• Support formal testing cycles: integration testing, UAT, regression, and performance checks with clear release evidence.
• Contribute to release discipline: code reviews, documentation, change impact analysis, and controlled deployments.
• Maintain technical documentation and runbooks to improve operational resilience and reduce incident resolution time.
• Participate in an out-of-hours support rota when required (paid / controlled / not constant firefighting)., * Modern IBM i patterns/tools: SQLRPGLE, RDi, ACS, source control integration
• Integration tooling and formats: REST APIs, JSON/XML, EDI, message/file processing pipelines
• Knowledge of Web services on IBM i (HTTP APIs, service programs, API gateways/wrappers)
• Batch scheduling and workload control (job descriptions, job logs, performance analysis)
• Exposure to modern delivery practices: CI/CD, automated build/deploy scripting, regression automation
• Any experience modernising legacy RPG III toward ILE/free-format

What the systems support (business domain)

You'll work on applications that directly impact trading performance and customer outcomes, including:

• Order Management (capture, allocation, pricing, returns)
• Inventory (stock movements, adjustments, replenishment, accuracy controls)
• Warehouse processes (pick/pack/ship, dispatch confirmation, scanning feeds)
• Billing & Finance interfaces (invoicing, postings, reconciliation outputs)
• Carrier/shipping artefacts (labels, manifests, tracking data feeds)

What success looks like in the first 3-6 months

• You'll take ownership of one or more IBM i workflows and become a trusted point of contact for enhancements and incident resolution.
• You'll deliver changes with low defect rates-supported by better regression discipline and clearer documentation.
• You'll improve performance and reliability in at least one high-usage process through DB2 for i tuning and cleaner RPG structure.
• You'll contribute to modernisation: reducing brittle code, introducing reusable service programs, and improving integration boundaries.

• RPG development on IBM i / AS400

• Ideally RPG ILE and/or free-format RPG
• Modular programming, service programs, binding directories (where applicable)

• DB2 for i (SQL, performance thinking, indexing, commitment control)
• CL (job control, automation, wrappers, operational scripting)
• IBM i operational understanding: libraries, objects, job queues, subsystems, authority concepts, basic troubleshooting
• Experience working in structured environments (change control, testing discipline, production stability), * Commercial experience as an RPG Developer in IBM i / AS400 environments
• Strong troubleshooting skills across code + data layers, with a root-cause mindset
• Comfortable working with business stakeholders to clarify requirements and deliver stable solutions
• A quality-first approach: clean code, testing discipline, documentation, and controlled releases