Mario Vallejo

US Based early stage fintech startup, focused on providing childcare benefits from government programs to workers of our different clients. As one of the Tech Leads for the team my responsibilities include:

• Integrations with HRIS systems to make data transfer and benefit application more streamlined for our users
• Planning and designing new features and systems in a microservice heavy application distributed between many of AWS’ products, stacks, and networks
• After system design, dividing the work between sprints, making sure none of the engineers in the team are overworked and everyone’s clear on goals and what has to be done
• Full Stack development. This being a small startup, one has to wear many hats, from system design to infrastructure provisioning via AWS
• Keeping track of work for every feature stream I own, as to deliver on budget and on time

Worked via Terminal.io with a US based client focused on the trucking industry, handling freight all over the US, Canada, and parts of México. As the most senior engineer in the Carrier Experience team, my responsibilities included:

• Leading a project to make new Shipper onboarding “self-serve”, as it required an engineer to add the relevant data to the system, saving about 100 engineering hours a month.
• Maintaining our SMS and email platform integrations, creating features to distribute magic links to the different people involved, so they could check shipment status even if they didn’t have an account. This reduced the amount of “abandoned” shipments, shipments without proof of delivery,
• Making sure that the real time tracking data we received was forwarded correctly, either by API call or FTP file upload, to the different 3rd party data aggregators our customers required, adding monitoring to the different adapters, now being able to pinpoint the reason why synchronizing failed, rather than process the whole sync queue over and over on failure
• Helping in the migration of REST calls to GraphQL and worked closed with the Frontend team re-designing the user facing homepage, increasing user engagement and reducing canceled shipments, due to increased visibility and improved dashboards

Hired by a client to develop the backend and game engine libraries for an online mobile multiplayer video game. Requirements have included:

• Designing the GraphQL API to be distributed, resilient, and cheap to run while doing tens of thousands of connections a minute. Increased performance 10x on the same machine from their PHP prototype by porting to Phoenix / Elixir
• Creating client libraries for the game engine used by the game devs to connect efficiently to backend services
• Designing of metrics and monitoring, taking advantage of BEAM VM features, increasing availability and resiliency
• Dockerizing and configuring CI pipelines to deploy on pull request merge, eliminating mistakes that happened with their old FTP based deployment