Senior Partner IAM Engineer for CIAM & Auth0

Booking.com; Amsterdam; On-site; EUR 90,000 - 130,000; Full time

Benefits offered by this job

Health insurance

Free Headspace access

Pension plan

Annual time off

Job summary

Booking.com is seeking a hands-on Senior Backend/Identity Engineer to own authentication services across partner systems. You’ll design, build, run, and evolve services that broker authentication between Booking.com’s partner systems and the identity provider, Auth0, including data models, APIs, caching, and failure modes.

You will lead migration workstreams from legacy Perl to Auth0 on live traffic, implement coexistence strategies, dual-write, rollout and rollback plans, while maintaining the

Qualifications

• Strong grasp of OAuth 2.0, OpenID Connect, JWT, and session management.
• Experience running services in a cloud environment with production ownership: deployment, observability, alerting, and incident response.
• Clear written and spoken English with stakeholder communication habits.
• Reading and safely changing large legacy codebases; Perl knowledge is required.
• Experience migrating authentication from legacy systems to a new identity provider on live traffic.
• Independent, evidence-led investigation of production problems spanning multiple systems.

Responsibilities

• Build and operate backend services across partner authentication.
• Lead migration workstreams from legacy Perl to Auth0 with phased cutovers.
• Maintain and modify long-lived Perl services carrying production traffic.
• Configure and extend the identity platform in Auth0 and related components.
• Lead technical investigations for login-path incidents and anomalies.
• Measure login health and run controlled experiments on migration steps.
• Support engineers and reviewers; unblock integrations and share domain knowledge.
• Participate in on-call rotations with partner-visible blast radius.

Skills

OAuth 2.0

OpenID Connect

JWT

Session management

Perl

Java

CIAM

Education

Bachelor’s degree or equivalent

Tools

Auth0

Job description

Booking.com is seeking a hands-on Senior Backend/Identity Engineer to own authentication services across partner systems. You’ll design, build, run, and evolve services that broker authentication between Booking.com’s partner systems and the identity provider, Auth0, including data models, APIs, caching, and failure modes.

You will lead migration workstreams from legacy Perl to Auth0 on live traffic, implement coexistence strategies, dual-write, rollout and rollback plans, while maintaining the