About the role
What we are looking for?
We are seeking a Staff Frontend Software Engineer, Infra with 7+ years of experience building frontend applications at scale. This individual will be crucial in transforming Harmonic's frontend from "it works" to "it works flawlessly," ensuring reliability, performance, and developer enablement. We need someone who can drive technical decisions and mentor the team through complex migrations, especially those with experience from companies like LinkedIn due to the similar technical challenges in managing large databases of people.
What will you be doing?
- Fix core reliability issues: error boundaries, state management, data consistency.
- Optimize performance: virtualization for large datasets, bundle optimization, render performance.
- Build monitoring and observability to catch issues before users do.
- Establish testing strategies that prevent regressions.
- Create abstractions and patterns that help engineers ship faster without breaking things.
- Drive technical decisions and mentor the team through complex migrations.
About X5 Labs
X5 Labs is a stealth-mode AI startup building a work model for regulated enterprises. The company develops an ambient discovery platform that observes everything an employee does on their computer — watching screen activity, mouse movements, and keyboard inputs — then augments and enhances their workflows using custom AI models deployed end-to-end within the customer's environment.
Founded by repeat entrepreneurs with deep roots in Israeli Defense Force intelligence and AI research, X5 Labs is on its second venture together. The company focuses on large regulated enterprises, primarily in finance — serving top-tier banks and financial institutions with production-grade, self-hosted AI solutions.
X5 Labs operates as an applied research lab with an execution-first mindset. The team has academic AI backgrounds but prioritizes shipping production systems, deploying custom models, and delivering real customer value over publishing papers. The company buys its own GPUs rather than renting, self-hosts models, and maintains full control of its AI infrastructure stack.
Backed by Insight Partners and other top-tier investors with tens of millions in funding, X5 Labs is rapidly scaling — currently around 25 people with plans to grow to approximately 70 by end of year. The company has already closed seven-figure deals with top-5 US banks and is deploying its platform across multiple enterprise customers.
Required skills
Other roles at X5 Labs
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Job details
Salary
$200,000 - $280,000
Location
New York, United States
Experience
7+ years
Company
Funding
Total raised
$23M
Last stage
Series A
Investors
Founders
Bryan Casey
Co-founder
Max Ruderman
Co-founder
What happens next.
No applications, no recruiter spam. Just the intro.
Confirm the fit
A few questions to make sure this role is the right shape for you. Two minutes.
I pitch you to the company
I write the intro, send it to the founder, and handle the back-and-forth.
A meeting lands on your calendar
If they’re a yes, I book the chat. You show up — that’s the whole job-hunt.