Tech Lead: Experimentation Platform & Edge Delivery

Testifize; United Kingdom; Hybrid; GBP 90,000 - 130,000; Full time

Job summary

Testifize is a measurement and experimentation consultancy seeking a senior engineer to lead the technical side of a long-running client platform engagement. You will work embedded with the client teams, owning how experimentation and personalisation are delivered across a high-traffic retail web estate.

This tech-lead role requires clear communication, design discussions, and hands-on coding across the stack—feature-flagging, edge and caching layers, content platforms, and customer-data

Qualifications

• Excellent written and spoken communication to explain constraints to non-technical stakeholders.
• Hands-on production experience with flag-based experimentation platforms at scale: design, dataflow and caching.
• Experience with JS/TS, Node.js, SSR, CDN caching and edge compute (Akamai/Cloudflare/Fastly).

Responsibilities

• Own the feature-experimentation platform across web and edge delivery, including user-ID and audience plumbing.
• Lead edge-side experimentation and caching strategy for server-rendered pages.
• Maintain integrations for editors/PMs to run tests without deployments.
• Investigate misbehaving experiments and document fixes for analysts.
• Review experimentation code in pre/post-launch stages.
• Represent experimentation in architecture reviews and security sign-offs.
• Build onboarding material for engineers new to experimentation.
• Collaborate with product managers, engineers and analytics teams daily.

Skills

Communication

JavaScript/TypeScript

Node.js

SSR

Edge compute

Caching

Flag-based experimentation

Tools

Optimizely

LaunchDarkly

Statsig

Split

Job description

Testifize is a measurement and experimentation consultancy seeking a senior engineer to lead the technical side of a long-running client platform engagement. You will work embedded with the client teams, owning how experimentation and personalisation are delivered across a high-traffic retail web estate.

This tech-lead role requires clear communication, design discussions, and hands-on coding across the stack—feature-flagging, edge and caching layers, content platforms, and customer-data