Data Scientist II

Signifyd; Belfast City District; Hybrid; GBP 50,000 - 80,000; Full time

Benefits offered by this job

Stock Options

Annual Bonus

Pension match up to 8%

Health, dental, optical insurance

Generous annual leave

Cycle to Work

Parental leave

Learning budget

Job summary

Signifyd's Applied Decision Science team builds production ML models to assess transaction risk and automate fraud detection. This role partners with the merchant portfolio to optimize decisioning and reduce false positives.

You will write production and analytical Python code, work with Spark/Databricks on distributed pipelines, and contribute to experiments and model improvements in a remote-friendly environment.

Qualifications

• Degree in computer science or an analytical field.
• 3+ years of post-undergrad work experience.
• Strong verbal and written communication skills.
• Strong machine learning and statistical background.
• Proficient in Python coding and collaboration in a shared codebase.
• Practical SQL knowledge.
• Design experiments and collect data.
• Experience with distributed analytics and data tooling such as Spark and Databricks.
• On-call shifts as part of weekend rotation (Fri/Sat/Sun). Currently ~6 weekends per year.

Responsibilities

• Partner with the Business Unit Lead and their merchant portfolio to identify gaps in decisioning performance and implement solutions, with guidance from senior team members.
• Develop production ML models that identify fraud in collaboration with data scientists and ML engineers.
• Create automation to reduce repetitive manual work.
• Run experiments to identify optimal decisioning strategies balancing complexity and performance.
• Communicate complex ideas to a variety of audiences including Customer Success and Sales.
• Write production and offline analytical code in Python.
• Work with distributed data pipelines in Spark/Databricks/GCP.

Skills

Python programming

Machine learning

Statistical analysis

SQL

Experiment design

Distributed analytics

Spark

Databricks

Communication skills

Code review

Education

Bachelor's degree in CS or analytics

Tools

Spark

Databricks

Job description

At Signifyd, we help merchants confidently grow their businesses by building trusted relationships with their customers. Our advanced technology, combined with a team genuinely invested in our clients’ success, creates frictionless shopping experiences, approving more good orders, protecting revenue, and keeping customers happy.

Trusted by thousands of leading merchants across more than 100 countries, we securely process billions of transactions each year. Our people are the heart of everything we do, driving our mission forward with commitment, empathy, and creativity. Join us on our mission to empower confident, fraud‑free commerce by helping online retailers provide superior customer experiences and eliminate fraud. Learn about our company values here !

The Applied Decision Science (ADS) team builds production ML models and risk management tools that are the core of Signifyd's product. We help businesses of all sizes minimize their fraud exposure and grow their sales. We improve the e‑commerce shopping experience for everyone by reducing the friction experienced by good buyers and blocking fraudulent purchase attempts.

ADS builds and manages the entire decision stack - from designing and deploying the ML models that assess the riskiness of a transaction, to building the tools the Risk team uses to manage and fight fraud. We seek to standardize and automate repetitive work so we can spend more time on experiments and high‑leverage projects.

We value collaboration and team ownership. Data scientists in Signifyd are true “full stack” operators, requiring knowledge of how transaction information received via our API traverses its way through our system and into the models we are responsible for building. When you test a hypothesis at Signifyd, you’re responsible for the end‑to‑end development, deployment, and evaluation process. This is a massive responsibility, and no one should feel like they're solving a hard problem alone. Together we help each other develop our skillsets through peer review of experiments and code, group paper study to deepen our machine learning and statistical understanding, and frequent knowledge‑sharing through live demos, write‑ups, and cross‑team projects. All team members are expected and encouraged to weigh in as an external reviewer on a peer's idea or approach, regardless of level.

A couple quick notes on the Signifyd culture

• We’re no stranger to remote work. Most of our workforce (ICs and leaders) are primarily remote. We tend to gather individual teams together once a year. There is no travel requirement for this role.
• We are heavy Slack users.
• We are heavy users of generative AI tools. We dislike token‑maxxing, but enjoy the expansion of capabilities that have come with genAI. We ask that during the interview you don’t use genAI, as we want to know what you know.

Responsibilities

• Partner with the Business Unit Lead and their merchant portfolio to identify gaps in decisioning performance and implement solutions, with guidance from senior team members.
• Utilize existing, or build net new production machine learning models that identify fraud, in collaboration with other data scientists and machine learning engineers.
• Identify and build automation that reduces repetitive manual work.
• Run experiments to identify optimal decisioning strategies, balancing complexity and performance.
• Communicate complex ideas to a variety of audiences, from Customer Success and Sales, to limited interactions with external customers.
• Write production and offline analytical code in Python.
• Work with distributed data pipelines in Spark/Databricks/GCP.

Requirements

• A degree in computer science or a comparable analytical field.
• 3+ years of post-undergrad work experience required.
• Strong verbal and written communication skills.
• Strong machine learning and statistical background.
• Write code and review others' in a shared codebase in Python.
• Practical SQL knowledge.
• Design experiments and collect data.
• Experience with distributed analytics and data tooling such as Spark and Databricks.
• This role has on‑call shifts, as part of our weekend rotation, Fri/Sat/Sun. While the number of shifts is subject to change, currently it works out to about six weekends a year.

Nice to Have

• Previous work in fraud, payments, or e‑commerce.
• Data analysis in a distributed environment.
• A passion for writing well‑tested production‑grade code.
• Experience with AI coding agents and automation.
• Experience of running A/B tests in production environments.
• An advanced degree.
• Stock Options
• Annual Performance Bonus or Commissions
• Pension matched up to 8%
• ‘Day one’ access to great health, dental and optical insurance scheme
• Generous annual leave plus public holidays
• Cycle to Work Scheme
• Enhanced maternity and paternity leave (12 weeks full-pay for mums & dads, plus 12 weeks half-pay for mums)
• Regular paid social events organized by our social committee
• On‑Demand Therapy for all employees & their dependents
• Dedicated learning budget through Learnerbly

We are committed to equality of opportunity for all staff and applications from individuals are encouraged regardless of age, disability, sex, gender reassignment, sexual orientation, pregnancy and maternity, race, religion or belief and marriage and civil partnerships.

We also want to provide an inclusive interview experience for all, including people with disabilities. We are happy to provide reasonable accommodations to candidates in need of individualized support during the hiring process.