Senior Full Stack Engineer

Senior Full Stack Engineer role in the Acquisition squad at Bark, an online services marketplace. The role works equally on frontend and backend, focusing on the marketing stack and AI-powered internal tooling, and building customer-facing products that power growth. Fully remote; candidates must be based in Spain. Interview process: screening call with Talent Partner (30 mins), hiring manager stage (30/45 mins), technical task (60 mins), and values interview (45 mins).

Responsibilities

Work across the stack to build elegant, performant APIs, services and front-end experiences using Python and React/TypeScript; Build and integrate with the marketing technology stack, connecting third-party platforms and internal services; Work with Marketing to spot automation opportunities, then design and ship AI-powered internal tooling that removes manual work; Measure the impact of the tools built, using metrics such as adoption, efficiency gains, reduction in manual effort and overall business value; Build responsibly: bake in cost tracking, secret and PII hygiene, and a human review step before any AI-generated output goes live to customers; Collaborate with product managers, designers and marketing to move ideas quickly from prototype to production; Proactively propose and implement improvements to the codebase and architecture; Mentor and support other engineers, sharing knowledge and encouraging best practices across the team; Proactively evaluate emerging AI tools and frameworks, make recommendations, and drive adoption across the business; Help improve ways of working internally and with stakeholders

Requirements

4+ years of experience working with Python in a production environment; 4+ years of recent experience working with React; Ideally a 50/50 front-end and back-end split (open to a 30/70 split either way if the fit is right); Experience building scalable, high-performing web applications; Production MySQL experience and strong SQL skills; familiarity with NoSQL datastores; Experience building, maintaining, testing and documenting APIs to be used by other developers both internally and externally; Strong organisational skills; Ability to achieve goals in a highly innovative and fast-paced environment; Great communication skills; Comfortable working with AI-assisted development tools (e.g. Claude Code, Cursor) as part of your day-to-day workflow; Genuine interest in marketing and automation problems, and the aptitude to learn the domain quickly

Nice to have

Experience building or integrating marketing technology (MarTech) stacks (e.g. CRM such as HubSpot or Salesforce, CDP such as Segment, email/marketing automation such as Iterable, analytics such as GA4 or Amplitude, ad platforms such as Google Ads or Meta); Has built AI-powered tooling in production (LLM APIs such as OpenAI or Anthropic, agents or workflow automation) for non-technical teams; Familiarity with the AWS ecosystem; knowledge of SQS (or similar such as RabbitMQ), SNS (or Kafka) and how they are used; Experience with data stores like ElasticSearch, DynamoDB or similar; Experience with cloud monitoring systems, such as Datadog