Senior Integrations Engineer

About the Role

At Klaviyo, our mission is to help businesses grow by delivering personalized experiences powered by unique data insights. The ARIA team plays a crucial role in facilitating this mission by ensuring seamless integration of various SaaS systems, databases, and cloud infrastructures, enabling our clients to derive actionable insights and drive their business objectives.

The Senior Integrations Engineer will own how those systems talk to each other. Our landscape spans many systems, including Salesforce, NetSuite, Zendesk, Gainsight, Stripe, Workday, Greenhouse, Coupa, Zip, and Okta, unified through Snowflake, Workato, and a growing set of internal Python, JavaScript services running on AWS. You will design and build the integrations that move data across that estate reliably, securely, and at scale.

This is an architecture-minded build role. You will be trusted to choose the right pattern for each use case — synchronous API call, bulk load, event stream, or scheduled batch — and to explain the tradeoffs behind that choice. You will design API-first, contract-first interfaces that survive change, and instrument everything you ship so failures are visible, explainable, and quickly resolved.

You will partner closely with the Sales Systems, Finance Systems, People Systems, and IT teams, as well as with Product Engineering, translating business processes into resilient technical designs. You will work alongside ARIA's Integration Architect to shape those designs and to define the patterns and standards other engineers build on.

How You’ll Make a Difference

• Design and build integrations across Klaviyo’s GTS landscape — Salesforce, NetSuite, Zendesk, Gainsight, Stripe, Workday, Greenhouse, Coupa, Zip, Okta, Jira, Linear, and Snowflake — using Workato alongside custom Python and JavaScript services on AWS.
• Select the right integration pattern for each use case — request-response API, bulk or batch data movement, event-driven streaming, or publish-subscribe — and document the reasoning and tradeoffs so the decision holds up as requirements evolve.
• Architect scalable, fault-tolerant solutions that absorb growth in volume and complexity without a redesign, with idempotency, retries, backpressure, throttling, and rate-limit handling built in from the start.
• Build and consume REST, Bulk, and GraphQL APIs, taking an API-first, contract-first approach so interfaces are versioned, documented, and safe to change.
• Implement event streaming and event-driven architectures using services such as Amazon EventBridge, SQS, SNS, Kinesis, or Kafka to enable near-real-time data flow between systems.
• Own authentication and security for integrations — OAuth 2.0 flows, JWT, SAML, and disciplined management of keys and secrets — and ensure data handling meets Klaviyo’s security, privacy, and audit requirements.
• Instrument integrations for end-to-end error observability: structured logging, monitoring, alerting, dead-letter handling, and reconciliation, so problems surface before stakeholders report them.
• Participate in incident handling for GTS integrations — triage and mitigate, communicate status to affected teams, and run blameless post-incident reviews that convert root causes into permanent fixes.
• Automate manual work out of quote-to-cash, procure-to-pay, hire-to-retire, and support workflows, using Workato where low-code fits and custom code where it does not.
• Establish and champion integration standards, reusable patterns, and clear technical documentation, and mentor engineers and system administrators across GTS in applying them.

Who You Are

• You have 5+ years building and supporting enterprise system integrations, including hands-on ownership of production integrations across SaaS platforms, cloud services, and internal applications.
• You have deep experience with at least one major iPaaS platform — Workato, MuleSoft, Boomi, or Informatica — and move comfortably between low-code automation and writing custom code when the use case demands it.
• You know integration design patterns well and can explain when to choose synchronous versus asynchronous, event-driven versus batch, or point-to-point versus hub-and-spoke, along with what each choice costs.
• You have strong hands-on experience with REST, Bulk, and GraphQL APIs — designing, building, consuming, paginating, and debugging them at volume.
• You have worked with event streaming and asynchronous messaging, and you understand ordering, delivery guarantees, replay, and idempotency in practice rather than in theory.
• You are fluent in OAuth 2.0 and related authentication flows, and you treat security — least privilege, secret management, data classification, encryption in transit and at rest — as part of the design rather than a review step.
• You write production-quality Python and JavaScript, and you are comfortable building on AWS with services such as Lambda, EventBridge, SQS, S3, and Secrets Manager.
• You have hands-on experience with several of our core systems — Salesforce, NetSuite, Zendesk, Gainsight, Snowflake, Workday, Stripe, Coupa, Zip, Greenhouse, Okta, Jira, or Linear — and you get productive on unfamiliar platforms quickly.
• You build for observability and you have handled real incidents: you have been on call, debugged failures under time pressure, communicated clearly while doing it, and followed through on the root cause.
• You translate complex technical tradeoffs into terms non-technical stakeholders can act on, and you bring them to a decision.
• You take ownership end to end — requirements, design, build, testing, deployment, and long-term support — and you raise risks early.

Nice to Haves

• Certifications or deep platform expertise in Workato Developer, Mulesoft Developer.
• Familiarity with quote-to-cash, revenue recognition, or procure-to-pay processes and the financial controls that surround them.
• Working knowledge of data engineering practices such as Snowflake, dbt, change data capture, or ELT tooling for analytics-facing integration work.
• Experience applying infrastructure as code and CI/CD — Terraform, GitHub Actions — to integration deployments.
• Exposure to compliance-relevant environments such as SOX, SOC 2, or GDPR, including audit trails and segregation of duties.
• Experience in a high-growth SaaS environment where systems, processes, and priorities were changing quickly.

Why This Role Matters

The Senior Integrations Engineer role is pivotal to Klaviyo's strategic growth as it addresses the increasing demand for seamless integration of diverse technology platforms. Successfully integrating various SaaS applications and automating key processes will enable Klaviyo to offer unparalleled data-driven insights and efficiencies to our clients, fostering greater customer loyalty and engagement.

By driving innovation in integrations and automation, this role directly impacts our ability to scale and adapt to the fast-evolving market needs. It empowers us to offer robust, agile, and secure solutions that our customers can trust, ultimately contributing to Klaviyo’s reputation as a leader in personalized marketing solutions. The right candidate will have the opportunity to be at the forefront of transformative technology initiatives, shaping the future direction of our platform, and adding significant value to both the company and our clientele.