Tiago Miguel de Seixas

Senior Full-Stack Developer&Senior ESG Consultant

Lisboa, Portugal|Remote EU

Years Dev

12+

Years ESG

20+

Projects

15+

Clients

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About Me

A unique profile combining advanced technical skills with deep regulatory and sustainability expertise.

Development

Senior Full-Stack Developer with proven experience building high-performance web and mobile applications (React, React Native, Node.js, TypeScript) for international B2B clients in fintech, insurance, IoT, and energy. Frontend team leadership and junior developer mentoring.

ESG & Sustainability

Senior ESG Consultant with 12+ years in sustainability strategy, corporate responsibility, and regulatory compliance. Proven track record in double materiality assessments, CSRD/ESRS frameworks, and sustainability strategies for enterprise clients in banking, payments, hospitality, and industry.

Skills & Technologies

Languages

JavaScript (ES6+)TypeScriptPythonHTML5CSS3

Frontend

React.jsReact NativeNext.jsReduxTailwind CSSChart.jsD3.js

Backend & Data

Node.jsExpress.jsWebSockets (Socket.io)REST APIsMongoDBPostgreSQLRedis

Infrastructure

AWS (S3, EC2, Lambda)Firebase/FirestoreVercelGitCI/CDDocker

Methodologies

Agile/ScrumCode ReviewTechnical MentoringAPI Architecture Design

ESG & Sustainability

CSRD/ESRSGRI StandardsEU TaxonomyVSMESFDRSDGsDouble Materiality AssessmentStakeholder EngagementGap AnalysisSustainability ReportingESG Strategy & Action PlansClimate Transition Planning

Professional Experience

Development

Senior Frontend / Mobile Developer

Studio Graphene

Sep 2021 — Present

Development agency for international B2B clients. Frontend development leadership and junior developer mentoring.

Led frontend teams of 2-4 developersCross-platform web & mobile (React, React Native)Sectors: Automotive, Insurance, Banking, IoT, Energy

Full-Stack Developer & Founder

CORE Tech

2019 — Present

Independent technical practice focused on web platforms and SaaS tools with ESG/sustainability specialization.

Proprietary ESG SaaS platform (CSRD/GRI/ESRS)Full stack: React.js, Node.js, MongoDBData pipelines for sustainability reporting

ESG Consulting

Senior ESG Consultant

Sustentare | ESG for Companies

Apr 2021 — Present

Sustainability consulting for large organizations and SMEs. CSRD compliance projects, materiality processes, and strategic ESG advisory.

Clients: SIBS, Banco BPI, Real Hotels Group, KLX GroupDouble materiality assessments (CSRD/ESRS)C-suite stakeholder engagement

Founder & ESG Consultant

CORE | Sustainability & CSR

Nov 2013 — Present

Boutique consultancy at the intersection of sustainability strategy and technology.

Clients: Galp, SIBS, BPI, AKI (Adeo Group)CSR strategy, shared value, sustainability programsBanking, energy, payments & retail sectors

Selected Projects

A selection of work across development and ESG consulting

Insurance · UK

Confidential client

Cross-Platform Insurance App

Led frontend development of a cross-platform mobile application for a major UK insurance provider. Real-time claims processing, policy management, and customer communication.

React NativeTypeScriptReduxREST APIs

Automotive · UK

Confidential client

Automotive Fleet Dashboard

Built real-time data visualization dashboard for automotive fleet management. Interactive charts, live tracking, and performance analytics.

React.jsTypeScriptChart.jsD3.jsWebSockets

Industrial IoT

Confidential client

Industrial IoT Platform

Developed monitoring and analytics platform for industrial IoT sensors. Real-time data ingestion, alerting systems, and historical analysis.

React.jsNode.jsWebSocketsMongoDBAWS

Sustainability · Tech

ESG Reporting SaaS Platform

Proprietary platform for ESG data collection and regulatory reporting. Algorithmic mapping of sustainability standards (CSRD, GRI, ESRS).

React.jsNode.jsMongoDBExpress.js

Industrial · KLX Group

ESG Strategy & Double Materiality

Led ESG strategy development and complete double materiality assessment aligned with CSRD/ESRS. Stakeholder engagement methodology and C-suite workshops.

CSRD/ESRSDouble MaterialityStakeholder Engagement

Payments/Fintech · SIBS

Sustainability Report & ESG Strategy

Supported sustainability report development, ESG strategy, and materiality assessment for Portugal's largest payment infrastructure company.

CSRDMateriality AssessmentSustainability Reporting

Currently available for new projects

Let's Work Together

Available for freelance, contract, or consultancy engagements across the EU.

Remote EU · Lisboa, Portugal

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CV Consultant ESG (EN)CV Programmer (EN)

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