Martech Full Stack Developer

About USAt Leadtech, we've been redefining digital businesses since ****, creating innovative online solutions that reach millions of users every month. With a diverse team of over 700 members from 23+ nationalities, we're united by a passion for creativity and collaboration. We specialize in delivering user?centric experiences across web and mobile platforms, where people can connect with our products like never before. We're proud of our global reach and committed to fostering an inclusive workplace where every individual contributes to our shared vision of bringing cutting?edge projects to life. Learn more about our journey and mission on our page!About The RoleWe're looking for a MarTech Full?Stack Developer to join our Marketing Technology & AdTech team. This is not the kind of "full?stack" role where you'll spend your life centering buttons or debating border?radius values for three sprints. You'll be working at the intersection of engineering, attribution, internal tooling, and growth - building the systems that make campaign measurement reliable, data flows usable, and marketing teams less dependent on guesswork. You'll help us maintain and evolve the technical backbone behind tracking, postbacks, schemas, integrations, and internal tools. That includes working on our internal CRM/tooling, improving how marketing teams operate, and making sure data moves where it should, when it should, and in the format it should. You'll collaborate closely with performance marketers, product owners, developers, and data stakeholders, acting as a bridge between business needs and technical implementation. And just so we're clear: we don't really care what you studied or where. Computer Science, Physics, Philosophy, self?taught, bootcamp, or "learned by breaking production and fixing it later" - all valid. We care about what you can do, how you think, and how you take ownership. Also: if you use AI to move faster, think better, document clearer, or automate boring work - great. That's a plus.What You'll Be DoingAttribution & Tracking InfrastructureBuild and maintain attribution and tracking systems across web and app environments.Work with tools like GA4, Appsflyer, Adjust, and server?side/custom setups.Handle event deduplication, postback routing, conversion events, and parameter consistency.Define, maintain, and enforce tracking schemas across projects.Ensure tracking is not just implemented, but actually reliable and usable.Internal Tooling & CRMDevelop and extend features within our internal CRM and marketing tooling.Build internal UIs and workflows that help marketing teams operate more autonomously.Improve existing tools instead of rebuilding everything from scratch.Work on real, messy operational problems - not just clean abstractions.Data Flow & WarehousingPipeline campaign and attribution data into warehouses such as BigQuery.Ensure data quality, consistency, and availability for analysis.Align platform data, internal systems, and warehouse outputs (ideally without creating multiple conflicting truths).Collaborate with Data and Product on schema design and governance.Network Signaling & IntegrationsBuild and manage server?to?server integrations with ad networks.Develop APIs and middleware for event ingestion and delivery.Work with platforms like Meta, Google Ads, TikTok, Snapchat, etc.Support integrations related to monetization and subscriptions (e.g. RevenueCat).Monitoring, QA & DebuggingAutomate testing and monitoring of attribution and tracking flows.Investigate discrepancies between internal data, warehouses, and ad platforms.Catch issues before they become "performance dropped... or maybe tracking broke."Bring visibility and structure to systems that are usually invisible until they fail.Cross?functional CollaborationAct as a bridge between Marketing, Product, and Engineering.Work with POs, developers, and marketers to define tracking and data structures.Translate business needs into technical implementations (and push back when needed).Maintain and evolve schemas across teams and projects.RequirementsMust?haveStrong backend experience with Node.js, Typescript and Python.Experience with APIs, REST, webhooks, and server?to?server integrations.Solid understanding of tracking, attribution, or event?based systems.Experience building or maintaining data pipelines.Ability to work with SQL / NoSQL databases.Experience with cloud environments and serverless architectures.Strong ownership mindset - you improve systems, not just complete tasks.Strong communication skills in English (written and spoken). Spanish is nice to have.GCP Stack (Important)Experience With The Google Cloud Platform Ecosystem, EspeciallyBigQuery (data warehousing & analysis)Cloud Functions / serverless workloadsPub/Sub (event?driven systems)Cloud Scheduler (orchestration / jobs)Datastore / Firestore (operational data & lightweight storage)Highly Relevant for This RoleExperience defining and maintaining tracking schemas / event governance.Experience building or maintaining internal tools, CRMs, or operational dashboards.Comfort working across technical and non?technical stakeholders.Nice?to?haveFrontend experience with React, Next.js, Vue, or Astro.Strong fundamentals in HTML, CSS, and web performance.Experience with MMPs (Appsflyer, Adjust, Branch).Familiarity with ad platform APIs and tracking flows.Experience with subscription businesses and tools like RevenueCat.Exposure to CDPs, marketing automation, or product analytics tools.How We Think About BackgroundWe don't require a specific degree or a perfectly linear career.We Care Aboutwhat you've builtwhat you've ownedhow you solve problemshow you communicatehow you learnAI, Tools & Ways of Workingdebug fasterdocument betterautomate repetitive workexplore solutionsOur Values in PracticeSee it, fix itOwn the invisible workCommunicate clearlyBuild systems, not chaosStay curiousWhy Join UsWork on systems that directly impact growth and decision?makingReal ownership across Marketing, Product, and DataMix of backend, data, tooling, and MarTech infrastructureA role that's not boxed into one disciplineA team that values execution over buzzwordsThis Role Is a Great Fit Ifyou like solving messy, real?world problemsyou enjoy making systems reliable and understandableyou're comfortable between engineering, data, and businessBenefitsGrowth and career developmentAt Leadtech, we prioritize your growth. Enjoy a flexible career path with personalized internal training and an annual budget for external learning opportunities.Work?Life balanceBenefit from a flexible schedule with flextime. Enjoy free Friday afternoons with a 7?hour workday, plus a 35?hour workweek in July and August so you can savor summer!Comprehensive benefitsCompetitive salary, full?time permanent contract, and top?tier private health insurance (including dental and psychological services).25 days of vacation plus your birthday off, with flexible vacation options-no blackout days!Unique PerksIn our office in Barcelona you'll find it complete with free coffee, fresh fruit, snacks, a game room, and a rooftop terrace with stunning Mediterranean views.Additional benefits include ticket restaurant and nursery vouchers, paid directly from your gross salary.Join us in an environment where you're free to innovate, learn, and grow alongside passionate professionals. At Leadtech, you'll tackle exciting challenges and be part of a vibrant team dedicated to delivering exceptional user experiences.Equal Employment Opportunity EmployerLeadtech is an Equal Employment Opportunity (EEO) Employer, which means we encourage applications from people with different backgrounds, interests, and personal circumstances. Our team welcomes applicants regardless of their race, gender, age, religion, nationality, sexual orientation, and/or disabilities. All we need is your high energy, skills, and willingness to be a part of a great project!#J-*****-Ljbffr

Must?have Strong backend experience with Node.js, Typescript and Python. Experience with APIs, REST, webhooks, and server?to?server integrations. Solid understanding of tracking, attribution, or event?based systems. Experience building or maintaining data pipelines. Ability to work with SQL / NoSQL databases. Experience with cloud environments and serverless architectures. Strong ownership mindset - you improve systems, not just complete tasks. Strong communication skills in English (written and spoken). Spanish is nice to have. GCP Stack (Important) Experience With The Google Cloud Platform Ecosystem, Especially BigQuery (data warehousing & analysis) Cloud Functions / serverless workloads Pub/Sub (event?driven systems) Cloud Scheduler (orchestration / jobs) Datastore / Firestore (operational data & lightweight storage) Highly Relevant for This Role Experience defining and maintaining tracking schemas / event governance. Experience building or maintaining internal tools, CRMs, or operational dashboards. Comfort working across technical and non?technical stakeholders. Nice?to?have Frontend experience with React, Next.js, Vue, or Astro. Strong fundamentals in HTML, CSS, and web performance. Experience with MMPs (Appsflyer, Adjust, Branch). Familiarity with ad platform APIs and tracking flows. Experience with subscription businesses and tools like RevenueCat.

Exposure to CDPs, marketing automation, or product analytics tools. How We Think About Background We don't require a specific degree or a perfectly linear career. We Care About what you've built what you've owned how you solve problems how you communicate how you learn AI, Tools & Ways of Working debug faster document better automate repetitive work explore solutions Our Values in Practice See it, fix it Own the invisible work Communicate clearly Build systems, not chaos Stay curious Why Join Us Work on systems that directly impact growth and decision?making Real ownership across Marketing, Product, and Data Mix of backend, data, tooling, and MarTech infrastructure A role that's not boxed into one discipline A team that values execution over buzzwords This Role Is a Great Fit If you like solving messy, real?world problems you enjoy making systems reliable and understandable you're comfortable between engineering, data, and business Benefits Growth and career development At Leadtech, we prioritize your growth. Enjoy a flexible career path with personalized internal training and an annual budget for external learning opportunities. Work?Life balance Benefit from a flexible schedule with flextime. Enjoy free Friday afternoons with a 7?hour workday, plus a 35?hour workweek in July and August so you can savor summer! Comprehensive benefits Competitive salary, full?time permanent contract, and top?tier private health insurance (including dental and psychological services). 25 days of vacation plus your birthday off, with flexible vacation options-no blackout days! Unique Perks In our office in Barcelona you'll find it complete with free coffee, fresh fruit, snacks, a game room, and a rooftop terrace with stunning Mediterranean views. Additional benefits include ticket restaurant and nursery vouchers, paid directly from your gross salary. Join us in an environment where you're free to innovate, learn, and grow alongside passionate professionals. At Leadtech, you'll tackle exciting challenges and be part of a vibrant team dedicated to delivering exceptional user experiences. Equal Employment Opportunity Employer Leadtech is an Equal Employment Opportunity (EEO) Employer, which means we encourage applications from people with different backgrounds, interests, and personal circumstances. Our team welcomes applicants regardless of their race, gender, age, religion, nationality, sexual orientation, and/or disabilities. All we need is your high energy, skills, and willingness to be a part of a great project! #J-*****-Ljbffr

At Leadtech, we've been redefining digital businesses since ****, creating innovative online solutions that reach millions of users every month. With a diverse team of over 700 members from 23+ nationalities, we're united by a passion for creativity and collaboration. We specialize in delivering user?centric experiences across web and mobile platforms, where people can connect with our products like never before. We're proud of our global reach and committed to fostering an inclusive workplace where every individual contributes to our shared vision of bringing cutting?edge projects to life. Learn more about our journey and mission on our page!