Software Development Engineer in Test (SDET)

Who Are Massive Rocket?

Massive Rocket is a rapidly scaling Braze and Snowflake agency on a mission to transform how digital marketing, product, and engineering teams connect. In just five years, we’ve grown at speed and are now gearing up for our next big milestone: hitting $100M in revenue. We build human experiences at scale, powered by cutting-edge web, mobile, cloud, data, and AI technologies. If you’re excited by innovation, love solving complex challenges, and want to help shape the future of digital experiences, you’ll feel right at home here.

Every role at Massive Rocket is entrepreneurial. The people who thrive here don’t just focus on their own remit - they understand the goals of the teams around them and actively contribute to the success of their colleagues, customers, and partners. We’re building a culture of ownership, collaboration, and growth, and we’re looking for people who want to make a real impact.

Who Are We Looking to Add to Our Team?

As an SDET (Martech & Data) at Massive Rocket, you’ll design, build and maintain the automated testing architecture that protects the integrity, reliability and velocity of a customer data ecosystem. This is a fixed-term contract role. Working within an embedded team, you’ll be the engineering gatekeeper of the “Golden Record” as the core stack is optimised, including Databricks, mParticle, Braze, OneTrust and ThoughtSpot.

Rather than checking files by hand, your focus is writing code that tests code. You’ll build automated validation frameworks for complex data pipelines, simulate user behaviour across web and app SDKs, mock cross-platform API integrations, and make sure automated personalisation and experimentation frameworks scale without regression. You’ll work closely with Data Engineers to triage anomalies, resolve pipeline failures quickly and stop issues coming back.

You’ll thrive here if you enjoy building test automation frameworks from scratch, owning defects end to end, and keeping data accurate, compliant and ready for activation.

What Will You Do?

• Design and implement automated validation frameworks that test data contracts, schema compliance and identity resolution/stitching logic in Databricks before data reaches downstream activation channels
• Build and maintain automated UI and behavioural test scripts that simulate real-world customer journeys across web and app
• Verify programmatically that behavioural events, mParticle tags and OneTrust consent tokens fire accurately at the application layer
• Validate high-criticality data flows across the Databricks > mParticle > Braze > OneTrust ecosystem
• Write automated integration scripts and mock API payloads to confirm actions propagate and correctly suppress or activate users across platforms
• Design and run end-to-end tests for data collection pipelines (POS, Web, App, CRM), making sure data is cleaned, standardised and transformed accurately for downstream use
• Validate data freshness and latency against near real-time SLAs
• Establish and maintain automated data validation and hygiene rules that detect corrupted records and schema drift in near real-time
• Audit data flows to make sure consent and preference management is strictly followed across every system, in line with global privacy regulations such as GDPR and UK GDPR

What Makes You a Great Fit

• Mastery of SQL for complex data validation, including writing scripts that identify anomalies across millions of records
• Proficiency in Python for building automated test suites and interacting with APIs
• Proven experience establishing data test automation frameworks from scratch
• Hands-on experience testing within Databricks (or an equivalent cloud lakehouse/warehouse), with a deep understanding of Delta Lake or similar architectures
• Proven experience validating complex data transformations across near real-time/streaming and batch pipelines, with familiarity with orchestration tools such as Airflow or dbt
• Experience validating data flows through a Customer Data Platform, particularly mParticle, including event ingestion, identity resolution and audience syncs into downstream engagement platforms
• Skill in triaging data anomalies, tracking pipeline failures in tools like Jira and working closely with Data Engineers to resolve issues quickly and prevent regression
• Experience testing REST APIs and validating data payloads between systems (for example, checking that a POS event correctly triggers a Braze data point)
• A Bachelor’s degree in Computer Science, Data Engineering or a related technical field

Bonus points if you have:

• Familiarity with how data is ingested into Braze via the Data Track API or Cloud Data Ingestion (CDI)
• Experience testing CDP-to-engagement data flows, such as mParticle audience syncs and event forwarding into Braze
• Experience testing privacy compliance and consent frameworks using tools like OneTrust
• Experience embedding data quality checks into CI/CD pipelines (GitHub Actions, GitLab CI)

Why You’ll Love Working Here

Rocket-Fuelled Growth - Big challenges, fast learning, and the chance to level up quicker than anywhere else

A Culture That Actually Gives a Damn - Supportive, positive, and built around people who want to see you win

A Global Crew - Collaborate with brilliant teammates across Europe, the US, and beyond

Remote-First for Life - Work from wherever you feel your best

Real Career Momentum - Clear progression, real ownership, and space to grow into your next chapter

Moments That Matter - Meetups, events, and team experiences that make the journey unforgettable

A Few Things to Know Before We Get Started

Bring Your Own Device - We operate a BYOD policy, so you’ll use your own kit for work

Right to Work - You’ll need a valid work visa; we’re not able to offer sponsorship at the moment

ID Checks - We may ask for proof of identity (passport, ID card, or a recent utility bill)

References - We may request two references, so have names, relationships, and contact details ready

A Quick Note on Applications

We receive a high volume of applications, and while we’d love to reply to everyone personally, it’s not always possible. If you haven’t heard from us within two weeks, it sadly means you haven’t been successful this time. But don’t let that stop you-we’re growing fast, and new opportunities open up all the time.