Marcelo Sousa Ribeiro.

London, UK

Building an agentic AI platform that connects LLMs to the business tools people already use (HubSpot, Salesforce, Gmail) and to third-party MCP servers, so an agent can carry out real multi-step work.

• Built the agentic core connecting LLMs to business tools and connectors via LangChain and Composio, including third-party MCP servers.
• Designed credit-based agent workflows for multi-step tasks: analyzing analytics and graphical data, preparing events, and drafting OKRs.
• Wired multi-model LLM access through OpenRouter with vector-database retrieval and agentic orchestration.
• Shipped the full stack end to end — backend, frontend, and mobile.

One of the lead developers on the hotel guest journey, building the in-hotel digital compendium (amenities, room service, upgrades) across frontend and backend, deployed to tens of thousands of hotels.

• Built a significant part of the compendium across frontend and backend (Stripe, Python, TypeScript).
• Built and launched Apple Wallet / Google Wallet mobile keys, integrating Apple PassKit, Vostio, and Dormakaba SDKs.
• Built the tipping and feedback service, integrated with Google and TripAdvisor.

Led full-stack development of tools for UK local governments to manage council homes, tenants, and tenant–council communication, built to GOV.UK standards and accessibility requirements (Ruby on Rails, JavaScript, AWS).

• Led a team of 3 building and optimizing council-management tools.
• Built systems for benefits and payment collection from council homes.
• Brought UX and UI to GOV.UK accessibility standards, driving meaningful gains in tool adoption.
• Planned and executed deployment strategies that streamlined production releases and cut downtime.

Worked across the platform for the UK's leading food-delivery service, focused on database performance and a large-scale, multi-market sharding effort (Ruby on Rails, PostgreSQL, AWS).

• Drove the data-sharding effort — migrated a large monolithic database to UUID keys and split it across market areas (UK, EU, Emirates).
• Designed a migration strategy that broke a monolithic database into 20+ shards to handle major growth in user traffic.
• Optimized heavy queries through denormalization and index improvements, substantially improving load times.

Owned payments end to end and was a key developer in warehouse management and fulfillment, supporting a subscription business that grew past 2 million subscribers (Ruby on Rails, JavaScript, TypeScript, Vue.js, AWS).

• Owned the payments system end to end — recurring and gift subscriptions, gift cards, and multiple recurrence models, integrated with Recurly.
• Built the assignment logic determining which products shipped for each subscription chosen.
• Developed backend payment endpoints and optimized checkout flows.
• Contributed to warehouse management and fulfillment, integrating Pitney Bowes.

Led a team of 6 on a high-traffic marketplace for the game and hobby industry — 1,200+ online stores, ~2M orders/month, 5M monthly active users.

• Built an Elasticsearch cluster with geocode search over hundreds of millions of records, cutting unified search from 20+ seconds to ~1 second.
• Added frontend caching and a JSON layer to keep the high-traffic platform fast.
• Led a datacenter migration of 40+ servers/instances — DNS, PostgreSQL, MySQL, EC2, and S3.