Calin Gabriel Senior Backend Engineer · Node.js / TypeScript

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Endava — Enterprise Clients

Full-stack JavaScript delivery across Deutsche Telekom, NETS Scandinavia, and eLife Sciences.

Agency
§ 01

The context

Endava is a global technology consultancy that places engineers with major enterprise clients. Over nearly three years there, I rotated across projects for Deutsche Telekom, NETS (Scandinavian payments infrastructure), and eLife Sciences (UK academic publishing) — all full-stack JavaScript.

This period built my delivery baseline. Working across telecoms, payments, and academic publishing forced me to adapt quickly, understand unfamiliar domains, and contribute without needing a long ramp-up.

§ 02

What I built

eLife Sciences · UK

Scientific paper processing

Built a document-conversion system with Node.js, AWS S3, and Lambda that processed 2,000+ scientific papers daily. The React frontend handled submission, tracking, and collaborative workflows — optimized to render large document collections without choking the browser.

NETS · Scandinavia

E-commerce checkout system

Created a checkout with React and TypeScript supporting multiple payment methods including Klarna and cards. In payments, reliability is the requirement — every edge case affects money, reconciliation, or trust. This is where my attention to payment-critical code started.

For a contract buyer, this is the adaptability proof: I've already been the engineer dropped into unfamiliar enterprise domains and expected to become useful quickly without a long runway.

§ 03

Impact across clients

2,000+
Papers processed daily
3
Domains — telecom, payments, academic
2
Junior devs mentored
§ 04

What I took away

Agency work forces you to get productive in unfamiliar codebases and domains. After rotating through telecoms, payments, and academic publishing, I learned to start with the domain constraints, then narrow the technical work to what the client actually needed shipped.

This is also where I started mentoring — guiding two junior developers through React best practices and Node.js architecture. Teaching forced me to articulate what I knew and find the gaps in my own understanding. It made me a better engineer, not just a more senior one.

§ 05

Stack

ReactTypeScriptNode.jsAWS LambdaAWS S3Klarna