Principal NetSuite Developer

William Smith Group 1832; Barnard Castle; Hybrid; GBP 90,000 - 130,000; Full time

Benefits offered by this job

Pension Scheme

Life Assurance 6x Salary

Free Parking

Employee Assistance Programmes

Training and career development

Holiday Purchase Scheme

Holiday Loyalty Reward Days

Cycle to Work Scheme

Tech scheme and Employee Discounts

Job summary

William Smith Group 1832 Limited is implementing Oracle NetSuite as its core ERP platform with Celigo as the integration layer. The senior integration architect role focuses on architecture, design authority, and mentoring the team.

You will own end-to-end integration architecture, lead complex SuiteScript work, and collaborate with the IT Manager on the platform roadmap and Phase 2 manufacturing design.

Qualifications

• Substantial hands-on NetSuite SuiteScript development experience (4+ years, all major script types, production track record).
• Deep working experience of Celigo integrator.io - flow architecture, error handling at scale, complex transformations.
• Demonstrable design and architectural responsibility on a NetSuite implementation or estate - not solely build-to-spec experience.
• Strong NetSuite data model fluency: saved searches, custom records, scripted vs. workflow trade-offs, governance and performance considerations.
• Experience operating as a senior individual contributor - code review, mentoring, technical decision-making.

Responsibilities

• Act as design authority for NetSuite customisation and integration: architectural decisions, technical standards, code review, design sign-off on non-trivial work.
• Lead the design and build of the most complex SuiteScript work (Map/Reduce at scale, performance-critical Suitelets and RESTlets, advanced workflow logic) and act as escalation point for the team on technical problems.
• Own the integration architecture end-to-end: flow design patterns, error handling and recovery, monitoring strategy, onboarding of new endpoints, retirement of legacy integrations when required.
• Establish and maintain platform engineering disciplines: SuiteCloud Development Framework, source control, sandbox and release management, deployment pipelines, governance limit monitoring.
• Mentor and upskill the existing development team through pairing, structured knowledge transfer, code review and technical coaching.
• Partner with the IT Manager on platform roadmap, technical debt management and Phase 2 (manufacturing) technical design.
• Engage directly with business stakeholders on the most complex requirements; translate to technical design and supporting documentation.
• Contribute to third-line support as escalation specialist for the most complex incidents.

Skills

SuiteScript 4+ yrs

NetSuite integration

Celigo integrator.io

Architecture design

Code review

Technical leadership

Mentoring

CI/CD

Tools

Salto

Git

CI/CD tooling

Job description

William Smith Group 1832 Limited is implementing Oracle NetSuite as its core ERP platform (go-live 1 November 2026), with Celigo as the integration layer, with Phase 1 covering core back-office functions, warehousing and distribution, and Phase 2 covering manufacturing functionality. The in-house development team - two Senior Developers and a further developer with growing NetSuite skills - delivers day-to-day platform development.

This role exists to add senior technical depth and specialist breadth to that team: owning the architecture of complex and cross-cutting work, leading on integrations, acting as design authority and technical reviewer, and accelerating the wider team’s capability through mentoring and code review. It is positioned as a senior individual contributor role, parallel to the IT Manager on the technical track, complementing rather than competing with the existing developers.

Key Responsibilities:

• Act as design authority for NetSuite customisation and integration: architectural decisions, technical standards, code review, design sign-off on non-trivial work.
• Lead the design and build of the most complex SuiteScript work (Map/Reduce at scale, performance-critical Suitelets and RESTlets, advanced workflow logic) and act as escalation point for the team on technical problems.
• Own the integration architecture end-to-end: flow design patterns, error handling and recovery, monitoring strategy, onboarding of new endpoints, retirement of legacy integrations when required.
• Establish and maintain platform engineering disciplines: SuiteCloud Development Framework, source control, sandbox and release management, deployment pipelines, governance limit monitoring.
• Mentor and upskill the existing development team through pairing, structured knowledge transfer, code review and technical coaching.
• Partner with the IT Manager on platform roadmap, technical debt management and Phase 2 (manufacturing) technical design.
• Engage directly with business stakeholders on the most complex requirements; translate to technical design and supporting documentation.
• Contribute to third-line support as escalation specialist for the most complex incidents.

Strongly preferred (tier 1)

• Substantial hands-on NetSuite SuiteScript development experience (4+ years, all major script types, demonstrable production track record).
• Deep working experience of Celigo integrator.io - flow architecture, error handling at scale, complex transformations.
• Demonstrable design and architectural responsibility on a NetSuite implementation or estate - not solely build-to-spec experience.
• Strong NetSuite data model fluency: saved searches, custom records, scripted vs. workflow trade-offs, governance and performance considerations.
• Experience operating as a senior individual contributor - code review, mentoring, technical decision-making.

Acceptable with development plan (tier 2 – alternative entry routes)

• Senior integration architect background on comparable platforms (Boomi, MuleSoft, Workato) with NetSuite exposure and willingness to specialise in Celigo.
• NetSuite SuiteCloud Developer II or Administrator certification.
• CPQ tooling experience.
• Manufacturing ERP functionality exposure (inventory, work orders, BOMs) - relevant to Phase 2.
• Git-based source control and CI/CD for NetSuite (Salto, Blue Yonder or equivalent tooling).
• SQL, Python or other scripting languages for tooling and data work.
• Manufacturing, distribution or food and beverage sector background.
• Experience with BI tooling (principally Phocas).

Personal Attributes

• Comfortable as senior technical voice without being the line manager - collaborative with both the IT Manager and the existing development team.
• Mentoring mindset; gets satisfaction from levelling up a team rather than hoarding the complex work.
• Pragmatic on engineering rigour - applies standards proportionately to the business context.
• Strong written and verbal communication with non-technical stakeholders.
• Committed to the agreed on-site working pattern

What the Role Offers

• Senior technical role on a newly implemented enterprise platform with a clear Phase 2 roadmap ahead.
• Genuine design authority and influence over the long-term technical direction.
• Strong existing team to work with and develop, not a green-field rebuild.

What we offer:

• Pension Scheme
• Life Assurance 6x Salary
• Free Parking
• Employee Assistance Programmes
• Training and career development
• Holiday Purchase Scheme
• Holiday Loyalty Reward Days
• Cycle to Work Scheme
• Tech scheme and Employee Discounts

Location: Barnard Castle, County Durham (hybrid – minimum 2 days on-site per week)

Job Type: Full-time, Permanent