Senior ServiceNow Developer

About the role

The Senior ServiceNow Developer is the technical authority for the ServiceNow platform supporting our cybersecurity managed services. The role designs, builds and maintains highly customised applications, integrates with security tooling and works directly with customers to deliver reliable, contract‑bound services.

Key responsibilities

• Act as technical authority: own architectural direction, set standards and provide final sign‑off before code promotion.
• Design and build scoped applications, custom data models and business logic beyond out‑of‑the‑box capability.
• Write, review and refactor advanced server‑side and client‑side JavaScript across Script Includes, Business Rules, GlideAjax, Scripted REST APIs, UI Scripts, UI Actions and Service Portal widgets.
• Work directly with customers to translate requirements into technical designs, explain trade‑offs and ensure operability within service contracts.
• Design robust integrations with external systems using REST, SOAP, OAuth and SSO, handling authentication, error handling and monitoring.
• Own platform health: performance tuning, technical debt reduction, upgrade impact analysis and remediation.
• Set and enforce coding standards, conduct peer reviews and drive measurable improvements in code quality.
• Serve as final escalation point for complex defects and production issues, performing root‑cause analysis.
• Mentor developers and administrators, growing team capability and reducing single points of knowledge.
• Produce and maintain technical documentation, integration specifications and runbooks.

Required profile

• Minimum 3 years of hands‑on ServiceNow development in heavily customised, multi‑application enterprise instances.
• Expert‑level JavaScript proficiency for both server‑side and modern client‑side scripting.
• Proven experience as the senior technical developer leading standards, code review and architectural decisions.
• Experience delivering ServiceNow in a managed‑service or MSP environment with direct customer interaction.
• ServiceNow Certified Application Developer (CAD) and Certified System Administrator (CSA) certifications.
• Ability to work autonomously, own end‑to‑end delivery and communicate technical trade‑offs in clear English.

Required skills

• ServiceNow platform development (scoped applications, data model design, Business Rules, Script Includes).
• Advanced JavaScript (server‑side, client‑side, debugging, performance‑conscious code).
• REST and SOAP integration, OAuth and SSO patterns.
• Flow Designer, Scripted REST APIs, GlideAjax.
• CI/CD practices with update sets, application repositories, ATF.
• Performance tuning, upgrade impact analysis and remediation.

What we offer

• Flexible working options.
• 25 days holiday plus bank holidays and the ability to purchase up to 5 additional days.
• Medicash & Critical Illness Scheme.
• Pension, Life Assurance and Share Save Scheme.
• Community volunteering programmes.
• Green Car Scheme and Cycle‑to‑work scheme.
• Special time off for major life events.
• Generous maternity and paternity leave and support for fertility treatments.