Software Engineer II - Platform Anti-Abuse

Klaviyo•Boston, MA

4h•Onsite

About The Position

The Core Infrastructure – Identity & Organizations (Core IO) pillar owns the foundational substrate for identity, access, organizations, and platform integrity at Klaviyo. We manage the critical path of the user journey from login, to enforcing permissions, to operating within the correct organization and regional context so that the rest of the platform can move fast and stay secure. Within Core IO, the Platform Anti-Abuse (PAA) team defends Klaviyo's customers, their recipients, and Klaviyo's brand by preventing fraud, abuse, and violations of our Acceptable Use Policy and Terms of Service across all channels. We build the automated detection systems, rules-driven enforcement services, and shared platform tooling that keep Klaviyo's platform safe; and we partner closely with Compliance, Security, and product teams to make "doing the safe thing" the default for every new surface and API.

Requirements

2-5+ years of professional software engineering experience.
Proficiency in at least one of Python or Go, and comfort working on backend and/or service-oriented systems, including web services or APIs backed by relational databases and/or caches (e.g., MySQL, Postgres, Redis).
Comfort reasoning about detection, classification, or enforcement systems;whether rules engines, content evaluation, or risk signals and the trade-offs between precision, recall, and system performance.
Exposure to CI/CD pipelines and modern development workflows (code review, testing, deployments, on-call participation or support).

Nice To Haves

Experience building detection or classification systems; rules engines, content classifiers, anomaly detection, or fraud/risk scoring and reasoning about signal quality, false positive rates, and coverage.
Familiarity with ML model integration in production systems: calling model endpoints, processing outputs in rules pipelines, and monitoring model-driven decisions.
Working with cloud-native infrastructure (AWS, Kubernetes, Terraform, or similar) and building services designed to run at scale.
Exposure to compliance or policy enforcement domains (AUP/TOS enforcement, content moderation, fraud detection) and how platform decisions in these areas are made and measured.
Familiarity with observability stacks (Grafana, Datadog, Sentry, Splunk) and using them to drive reliability and detection-quality improvements.
Interest or experience in adjacent Core IO domains like Identity & Access Management or Organizations, especially where they intersect with account security, fraud signals, and org lifecycle.

Responsibilities

Own features end-to-end across design, implementation, rollout, and observability for abuse detection and enforcement capabilities; rules, classifiers, enforcement pipelines, and the platform services that other teams plug into.
Extend abuse enforcement to new product surfaces: Help bring anti-abuse rules and enforcement to product areas where coverage is currently limited, ensuring consistent policy application across channels.
Build content and link abuse detection systems: Help design and implement detection capabilities for malicious URLs, abusive image content, and other content-level signals;combining perceptual hashing, ML model integrations, and rule-based approaches.
Contribute to AUP automation and enforcement pipelines: Help build and scale the systems that automatically evaluate accounts against our Acceptable Use Policy, reducing reliance on manual compliance review.
Improve platform anti-abuse infrastructure: Evolve microservices, rules orchestration layer, and abuse observability pipelines; making them faster, more reliable, and easier for the team and compliance stakeholders to operate.
Help define and refine standards for how other teams integrate with PAA's detection and enforcement APIs; so product teams can add abuse coverage to new areas without reinventing detection logic per service.
Collaborate closely with partner teams: Work with Identity & Access Management (IAM) on authentication & authorization signals, with Organizations on account lifecycle and policy enforcement, and with Security and Compliance on AUP/TOS enforcement patterns.
Improve reliability and observability of anti-abuse services by instrumenting metrics and alerts, maintaining abuse impact dashboards, and contributing to on-call rotations and incident reviews.