Senior ServiceNow Developer

NCC GroupRijswijkHybridFull-time6 Oct 2026

Senior ServiceNow Developer needed to act as the most senior hands-on technical authority for the ServiceNow platform underpinning cybersecurity managed services in Rijswijk, Netherlands. Requires expert-level JavaScript, complex custom application development, integrations, and technical leadership, with a minimum of 3 years in heavily customised enterprise instances.

What you'll do

Act as the technical authority for the platform: own architectural direction and technical standards, make and document the significant design decisions, and provide the final technical sign-off before code is promoted.
Design and build scoped applications, custom data models and business logic that go well beyond out-of-the-box capability, while keeping the instance supportable and upgradeable.
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, applying sound engineering practice within the constraints of the platform.
Work directly with customers and service stakeholders to shape requirements into technical designs, explain trade-offs and constraints in plain language, and ensure what is delivered is operable within the managed service and its contractual commitments.
Design and build robust integrations with external systems, security tooling and customer platforms using REST and SOAP, including authentication, error handling, retry behaviour and monitoring.
Own the technical quality of a heavily customized, multi-customer set of instances: performance tuning, reduction of technical debt, upgrade impact analysis and remediation of skipped or broken customisations.
Set and enforce coding standards, secure development practice and peer review across the team, and drive consistent, measurable improvement in code quality.
Act as the final escalation point for the most complex defects and customer-impacting production issues, including root cause analysis across integrations, ACLs, asynchronous processing and performance, and communicate findings to service and customer stakeholders.
Coach developers and administrators through pairing, design reviews and technical walkthroughs; grow the technical depth of the team and reduce single points of knowledge.
Produce and maintain technical documentation, integration specifications and runbooks to a standard that allows others to support and extend the work.
Work closely with ServiceNow administrators, frontend developers, UX and service delivery colleagues to ensure solutions are implemented and operated seamlessly end to end.

What you need

Must-have

ServiceNowJavaScriptScoped ApplicationsBusiness RulesScript IncludesGlideRecordGlideAggregateACLs

Nice-to-have

ReactJiraAzure DevOpsSIEMSOCVulnerability ResponseSecurity Operations

Soft skills

Technical LeadershipCommunicationMentoringAutonomyCollaborationProblem Solving

ServiceNowSenior DeveloperCybersecurityIT ServicesManaged ServicesJavaScriptHybridNetherlandsFull-timeTechnical Lead

/What you'll do

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Must-have

Nice-to-have

Soft skills

What you'll do

What you need