About this role.
Cresta is seeking a Senior Backend Engineer to join its Platform Team, focusing on building robust backend systems for agent assist integrations (chat/email) and scalable authentication solutions. As part of a well-funded AI startup backed by top investors, you will architect distributed systems that manage real-time conversation state, ensure high availability, and support enterprise-grade customer integrations. This role involves collaboration with frontend platform, ML, infra, and auth teams, as well as direct customer engagement to address integration challenges. Ideal candidates are versatile backend engineers with expertise in distributed systems, real-time communication, and IAM systems, looking to apply their skills to real-world AI systems in complex enterprise environments.
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Cover letter sample
I am writing to express my strong interest in the Senior Software Engineer, Backend - Platform Team position at Cresta. With a deep background in designing scalable distributed systems and real-time communication frameworks, I am excited by the opportunity to contribute to Cresta's AI-driven customer experience platform.
Your focus on enterprise-grade integrations and specialized authentication systems aligns perfectly with my expertise in building robust backend services and implementing secure IAM solutions. I have successfully led similar integration efforts for large-scale platforms, ensuring high availability and low latency.
I am particularly drawn to the chance to work at the intersection of backend engineering and AI, collaborating with diverse teams to solve complex challenges. My experience with containerization, cloud-native architectures, and cross-team collaboration would enable me to hit the ground running.
I look forward to the possibility of bringing my passion for engineering excellence and customer-centric development to Cresta and helping shape the future of conversational AI.
Sample interview questions
At my previous company, I designed a chat service that needed to handle millions of concurrent connections. Key challenges included ensuring low latency and reliable message delivery. We used WebSockets for real-time communication, implemented a pub/sub model with Redis, and used a message queue for persistence. To handle failover, we deployed multiple instances behind a load balancer and used health checks. We also implemented circuit breakers to prevent cascading failures.
I would start by defining the authentication flows: OAuth 2.0 for user authentication and API keys or JWT tokens for service accounts. For users, we'd use OpenID Connect for single sign-on. For service accounts, we'd issue long-lived credentials with scoped permissions. We'd store secrets securely using a vault service and enforce least privilege. Additionally, we'd implement rate limiting and audit logging to track usage.
High availability can be achieved by deploying across multiple availability zones and using auto-scaling groups. Low latency requires minimizing network hops, so we'd use edge caching and keep data in memory (e.g., Redis). For real-time communication, we'd use persistent connections (WebSockets) and handle reconnection gracefully. Monitoring and alerting (e.g., Prometheus, Grafana) would help identify bottlenecks quickly.
I led a project to integrate a recommendation system with our frontend and ML teams. We had weekly sync meetings to align on API contracts and timelines. I created a shared document tracking dependencies and milestones. To avoid blockers, we used feature flags to deploy incrementally. Regular demos ensured everyone was on the same page. The key was proactive communication and setting clear expectations.
First, I'd identify the severity and impact, then triage based on customer SLA. I'd check dashboards and logs to pinpoint the issue (e.g., latency spike, error rate). If it's a known pattern, I'd apply a hotfix or rollback. For unknown issues, I'd replicate in a staging environment and use debugging tools. After resolution, I'd conduct a post-mortem to implement preventatives like better monitoring or automated tests.
Cresta unlocks the true potential of the customer experience, turning every conversation into a competitive advantage. Cresta’s unified AI platform combines conversational AI agents, real-time human agent augmentation, and comprehensive conversation intelligence to drive revenue and efficiency gains across every channel. The world’s leading companies, including United Airlines, Cox Communications, and Marriott, use Cresta to power world-class customer experiences every day.
Born from the Stanford AI Lab, Cresta has raised more than $270 million from the world’s leading investors, including a16z, Greylock, and Sequoia. Cresta’s leadership includes some of the leading minds in AI today. Our CEO, Ping Wu, founded and led Google’s Contact Center AI and Vertex AI platforms before joining Cresta to build the future of AI-driven customer experiences.
Over the next few years, AI is going to redefine how people all over the world interact with businesses every day. Come build that future at Cresta.
About the role:
Cresta’s Core Platform underpins the company’s entire product portfolio. Our long term vision is to build a robust, reliable, secure, and extensible foundation that supports continued innovation, satisfies enterprise customer requirements, and keeps operational costs in check. Two critical components for that are agent assist backend services and scalable authentication systems, tools, processes and frameworks based on industry standards and security best practices.
This role is focused on building various backend systems needed to enable successful customer integrations:
- Enable agent assist integration for chat and email. This involves working with the frontend platform team, ML teams, infra team and other backend services.
- Expand our backend agent assist services to meet customer requirements and feature requests.
- Address any customer issues that block integrations, affect user experience or system performance.
- Work with the auth and security team to meet Cresta’s diverse authentication and security needs for internal workflows and external customer facing integrations.
We are looking for strong versatile backend engineers who want to work at the intersection of distributed systems, real-time communication, enterprise integrations, and IAM systems.
Why This Role Is Unique:
- Enterprise-Grade Integrations: Design robust integrations with major CCaaS platforms and customer systems.
- Specialized Auth Experience: Join the Cresta auth team and help build specialized authentication systems to authenticate users, service accounts, virtual agents, server workloads, cloud based authentication for external integrations, etc.
- Agent Assist Integrations: Work directly with the frontend platform team to build solutions for agent assist integrations for various channels such as chat and email and help rollout these integrations in customer environments.
If you’re a strong backend engineer who wants to apply your expertise to real-world AI systems operating inside complex enterprise ecosystems, and expand your expertise in auth, this role offers that opportunity.
Responsibilities:
- Contribute to building the best-in-class company in addition to building the best-in-class product.
- Architect systems that manage real-time conversation state, context propagation, and session lifecycle.
- Play a substantial role in the agent assist integration process (chat and email) and authentication engineering team.
- Work with Cresta product and engineering teams, build and continuously improve the Cresta platform and new product requirements.
- Stay closely with customers and their requirements, analyze the technical tradeoffs, own the customer facing deliverables.
- Demonstrate the engineering best practices in deliverables and daily work. Uphold others to the same high standards.
- Technical ownership in a substantial part of the Cresta authentication stack.
- Ensure high availability, low latency, and strong observability for real-time conversation systems.
- Implement authentication, authorization, compliance, and enterprise security best practices across integrations.
- Drive improvements in reliability, performance, and scalability in production environments handling high interaction volumes
Qualifications We Value:
- Bachelor’s degree in Computer Science or related field.
- 5+ years of experience building scalable backend systems in production environments.
- Strong experience designing and maintaining robust APIs (REST, gRPC).
- Solid understanding of distributed systems and real-time communication architectures.
- Experience integrating with third-party enterprise platforms and APIs.
- Experience working with CCaaS platforms or contact center systems is a strong plus.
- Familiarity with AI Agents, Virtual Agents, or LLM-based systems is a plus.
- Experience with containerized environments (Kubernetes, Docker).
- Experience with cloud platforms such as AWS, GCP, or Azure.
- Strong understanding of system reliability, observability, and security in enterprise environments.
- Experience in building authentication systems is a plus.
Perks & Benefits:
- We offer Cresta employees a variety of medical, dental, and vision plans, designed to fit you and your family’s needs
- Paid parental leave to support you and your family
- Monthly Health & Wellness allowance
- Work from home office stipend to help you succeed in a remote environment
- Lunch reimbursement for in-office employees
- PTO: 3 weeks in Canada
Compensation for this position includes a base salary, equity, and a variety of benefits. Actual base salaries will be based on candidate-specific factors, including experience, skillset, and location, and local minimum pay requirements as applicable. We are actively hiring for this role in the US and Canada. Your recruiter can provide further details.
This posting will be used to fill a newly-created role.
We have noticed a rise in recruiting impersonations across the industry, where scammers attempt to access candidates’ personal and financial information through fake interviews and offers. All Cresta recruiting email communications will always come from the @cresta.ai domain. Any outreach claiming to be from Cresta via other sources should be ignored. If you are uncertain whether you have been contacted by an official Cresta employee, reach out to recruiting@cresta.ai
Annual salary information is not provided for this position. Explore salary ranges for similar roles in our Salary Directory ›
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