This job is posted on behalf of Top Echelon Software by Top Echelon.
Senior PHP Engineer – CATS Platform AI Features
Top Echelon Software is seeking a Senior PHP Engineer to help own and evolve CATS, our established SaaS applicant tracking system running in AWS.
This is a hands-on role combining production ownership, thoughtful modernization, and practical AI development. You’ll maintain a product customers depend on, improve how we build and deliver software, and develop AI-enabled features that help recruiters work more effectively.
This is a full-time role based in Canton, OH. U.S. work authorization required.
About the role
CATS is a mature, revenue-generating product with an established customer base and a substantial codebase. We’re looking for an engineer who enjoys understanding complex systems, making sound technical decisions, and delivering improvements incrementally.
You’ll take primary engineering responsibility for application health and contribute directly to its evolution. That includes resolving production issues, improving performance and maintainability, using AI coding assistants effectively, and turning promising AI capabilities into reliable product features.
Our stack includes PHP, MySQL, Vue, JavaScript/TypeScript, REST and GraphQL APIs, Redis-compatible caching and queues, OpenSearch, Docker, and AWS infrastructure. The application combines established legacy code with newer components, including integrations for embeddings and vector search.
What you’ll do
- Own application reliability, maintenance, and targeted enhancements.
- Diagnose production issues across application code, database queries, background jobs, integrations, and deployment infrastructure.
- Modernize selected areas of the codebase while preserving customer workflows and backward compatibility.
- Improve automated tests, static analysis, observability, CI/CD, and operational documentation.
- Use AI coding assistants for code exploration, implementation, debugging, and testing, while remaining accountable for correctness and security.
- Develop repeatable AI-assisted engineering workflows that produce small, tested, reviewable changes.
- Build and extend AI-enabled capabilities such as semantic search, summarization, information extraction, and recruiter workflow assistance.
- Evaluate AI features for usefulness, accuracy, latency, cost, and reliable behavior when dependencies fail.
- Protect customer and candidate data through appropriate access controls, tenant isolation, and careful handling of data sent to AI services.
- Help prioritize technical debt and provide clear input on roadmap feasibility, tradeoffs, and risk.
Required experience
- Substantial professional software development experience, typically 7+ years, with deep PHP expertise.
- Experience maintaining and improving a complex, long-lived application.
- Strong MySQL/SQL skills, including query optimization, indexing, and safe data changes.
- Experience operating production SaaS systems and diagnosing issues across multiple layers.
- Experience with APIs, third-party integrations, and asynchronous or background processing.
- Working proficiency in JavaScript/TypeScript and an ability to contribute to an existing frontend.
- Experience with Docker, automated testing, and CI/CD.
- Hands-on experience using AI coding assistants on real development work, including reviewing generated code and validating changes.
- Practical experience integrating LLMs or other AI services into an application, with an understanding of evaluation, failure handling, and data privacy.
- Ability to work independently, communicate tradeoffs clearly, and carry changes through deployment and follow-up.
Preferred experience
- Vue, particularly maintaining or modernizing Vue 2 applications.
- AWS services such as EKS, RDS, EC2, and S3; Kubernetes deployment and troubleshooting.
- OpenSearch/Elasticsearch, Redis/Valkey, and search relevance tuning.
- Embeddings, vector search, retrieval-augmented generation, and structured model outputs.
- Shipping and operating customer-facing AI features.
- Building agent-assisted development pipelines or “software factories”: repeatable workflows connecting specifications, implementation, tests, review, and release controls.
- Technical ownership of a mature SaaS product or experience working on a small engineering team.
- Recruiting, applicant tracking, or other workflow-intensive business software.
What success looks like
- Customers can depend on CATS, and recurring production problems become less frequent.
- Improvements ship in manageable increments with appropriate testing and clear rollback options.
- AI-assisted development improves delivery speed without sacrificing quality.
- AI features solve measurable customer problems and behave reliably in production.
- Documentation and tooling make the platform easier for others to understand and support.
Benefits
Competitive salary, PTO and flexible floating holidays, 401(k) match, health benefits, and an education stipend.