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Photon

Builds custom software and AI for big companies

QA Engineer - Performance

Performance TestingConfirmed live in the last 24 hours
Full-timeUnited StatesIn-person

About the Job

Requirements

  • At least 8 years of experience in Performance Engineering, focused on AI/ML applications or high-concurrency distributed systems.
  • Expert-level experience with performance testing tools such as Locust, JMeter, or k6, customized for Python-based AI backends.
  • Strong ability to write Python scripts to simulate complex, multi-step user or agent interactions.
  • Understanding of LLM performance factors, including quantization, KV caching, and how model architectures affect latency.
  • Experience with observability tools such as Prometheus, Grafana, LangSmith, or Weights & Biases to monitor system health and AI-specific metrics.
  • Experience testing vector database query latency under heavy load.

Responsibilities

  • Measure and optimize time to first token and total request latency for complex agentic workflows involving multiple reasoning steps.
  • Simulate high-concurrency environments with hundreds of autonomous agents, focusing on API rate limits and GPU or compute bottlenecks.
  • Test vector database retrieval speed and efficiency, and identify how context-window size affects system performance.
  • Analyze tokens-per-second metrics and determine when switching from a large model to a smaller model is needed to maintain performance.
  • Create reports balancing performance gains against token costs to help identify an appropriate production performance and cost balance.
  • Use profiling tools to identify delays in handoffs between agents and between agents and external tools such as APIs and databases.
  • Integrate performance testing into the CI/CD pipeline to ensure prompt versions and architecture changes do not degrade agent speed.

About the Company

Photon

Builds custom software and AI for big companies

Photon designs, builds, and runs custom software for large companies, combining an in-house creative agency with its own engineering teams. Its flagship client work includes rebuilding Samsung's US online store as a set of smaller linked services and creating Olive Garden's mobile app, which lets diners join the waitlist from their phones instead of waiting at the door. Clients hire Photon's teams to plan and code their apps, websites, and AI tools and to keep them running afterward, paying for the engineers and designers assigned to each project. Photon is privately held and based in London, with its US arm in Dallas and engineering centers in Chennai and Bengaluru.

Company size
5,001-10,000
Company stage
Not listed
Total funding
Not listed
Headquarters
London, United Kingdom
Founded
Not listed

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