Software Engineer II - Platform Anti-Abuse

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you’re a close but not exact match with the description, we hope you’ll still consider applying. Want to learn more about life at Klaviyo? Visit klaviyo.com/careers to see how we empower creators to own their own destiny.

Team overview

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.

Why this role is exciting

• Fight real adversaries at scale: Abuse patterns evolve constantly;bad actors adapt, and so must your systems. You will build detection and enforcement capabilities that respond to emerging fraud patterns across email, SMS, and other channels, combining rules, signals, and ML to stay one step ahead.
• Your work is the platform's safety net: The rules engine and enforcement services your team owns are consumed by messaging, campaigns, flows, and nearly every sending channel at Klaviyo. Improvements you make protect millions of email and SMS recipients and directly affect platform trust and deliverability.
• Work at the intersection of rules, ML, and systems engineering: This role is unusually broad technically. You will build high-throughput Go services, Python rules pipelines, and integrate ML-based classifiers for content and URL abuse. Few platform roles combine adversarial problem-solving with this range of systems work.
• Automate policy enforcement at scale: Manual compliance review doesn't scale. We are building systems that automatically evaluate accounts against our Acceptable Use Policy and trigger the right enforcement actions; reducing human bottlenecks and making enforcement consistent across account types.

What you'll do

As a Software Engineer II on the Platform Anti-Abuse team, you will:

• 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 a