Job VC
Senior / Lead Full Stack Engineer - Backend Edge Detection
Company:
QAIL AI (qail.ai)
Team:
Founding Engineering
Location:
Remote (US time zones preferred)
Type:
Full-time · Senior/Lead
About QAIL
QAIL is building the intelligence layer for the agentic web. We detect and verify the AI agents and bots hitting our customers' websites in real time, qualify legitimate buying intent, and expose MCP endpoints that let autonomous agents discover and transact with businesses. Our detection runs at the AWS edge on CloudFront and Lambda@Edge, processes high-volume traffic with sub-second latency, and closes the loop back to ad platforms through Click ID attribution.
We're a small founding team moving fast on a category that's forming right now. You'll have real ownership over the systems at the core of the product.
The Role
We're looking for a senior/lead full stack engineer with deep backend strength to own — and set technical direction for — our edge detection and signal pipeline: the part of QAIL that sees every request, fingerprints it, and decides in milliseconds whether it's a human, a known AI agent, or something trying to look like one.
This is a high-throughput, low-latency problem. You'll be comfortable thinking about request volume, p99 latency, and the difference between what you can compute at the edge versus what belongs in the aggregation layer. As one of our most senior engineers, you'll make the architectural calls, set the standards the team builds against, and mentor as we grow. You'll touch frontend too — the customer dashboard and our embeddable detection script — but the center of gravity is backend and edge infrastructure.
What You'll Do
Build and own detection at the
AWS edge
(CloudFront + Lambda@Edge): User-Agent and ASN matching against published AI provider ranges, TLS fingerprinting (JA3/JA4), and request-shape signals — all before the page is served.
Design the
signal aggregation pipeline
that fuses edge signals, server-side behavioral data (timing, path depth, headers), honeypot/pixel hits, and fingerprint consistency into an identity and intent decision.
Engineer the system to handle
large traffic volumes
reliably and cheaply — latency budgets, backpressure, caching, and graceful degradation under load.
Build and maintain our
MCP endpoints
and attribution API that close the loop between agent activity and the customer's ad platforms.
Develop the
embeddable client script
(fingerprint capture, form integration) and contribute to the
real-time analytics dashboard
customers use to see bot traffic and lead quality.
Set technical direction
— own architecture decisions, establish engineering standards, review code, and mentor engineers as the team scales.
Make pragmatic architecture calls appropriate to our stage — ship, measure, iterate; no premature microservices.
Our Stack
Backend:
Java (primary) for core services and the signal pipeline; Python a plus. Edge functions (Lambda@Edge / CloudFront Functions) run in JavaScript/Node and Python.
Edge:
AWS CloudFront, Lambda@Edge
Detection signals:
TLS/JA3/JA4 fingerprinting, ASN/IP reputation, behavioral & timing analysis, browser fingerprinting
Protocols/APIs:
MCP (Model Context Protocol) endpoints, REST, Click ID attribution feedback
Frontend:
Modern JS/TS, React-based dashboard, vanilla JS/TS embeddable scripts
Infra:
AWS-native; managed services over self-hosted where the cost delta is modest
What We're Looking For
7+ years of backend engineering, with a track record building
high-traffic, latency-sensitive systems
(APIs, pipelines, or real-time services at scale).
Strong proficiency in
Java
(our primary backend language);
Python a plus
, plus comfort writing
edge functions in JavaScript/Node or Python
(Lambda@Edge / CloudFront Functions) and working across the full stack.
Hands-on experience with
AWS edge / serverless
(CloudFront, Lambda@Edge, Lambda) — or deep CDN/edge-compute experience you can transfer quickly.
Strong grasp of
HTTP, TLS, networking, and request lifecycle
fundamentals.
Demonstrated
technical leadership
: owning architecture, setting standards, and raising the bar for engineers around you.
A pragmatic, ownership-driven mindset suited to an early-stage team: you scope, build, and ship end to end.
Bonus Points
Background in
bot detection, anti-fraud, ad tech / mar tech, or web security
.
Familiarity with
fingerprinting techniques
(TLS, canvas/WebGL, behavioral) from either the detection or evasion side.
Experience with
MCP, agentic systems, or LLM application infrastructure
.
Startup experience strongly preferred
— you've thrived in an early-stage, high-ambiguity environment before.
Big plus if you've been a startup founder yourself
— you know what it takes to build from zero and own outcomes end to end.
What We Offer
A
founding-team seat
in an emerging category, with influence over product and technical direction.
High autonomy and direct ownership of core product systems.
Remote-first, fast-moving, low-bureaucracy environment.