Sebastian Sastre

5.0

(26 reviews)

US$25.00

For every 15 mins

Sessions/Jobs

First 15 mins free for your first session

ABOUT ME

I'll help with Software Engineering challenges in the full stack.

Senior software engineer with 23 years of production experience and 10+ years fully remote with US, Canadian, and European teams.

Deep in Rust, event-driven backend architectures, and distributed services.

Recent work: backend engineer at Kraken (Payward Inc.) contributing with several Rust high standards and high load microservices.

Prior: petabyte-scale roaming infrastructure at Telna; high-volume ad tech at Sulvo.

Active open-source author.

Maintainer of Shakedown, a Rust system-testing crate (pre-release mode at this time).

Earlier work includes Mapless and Flow for Pharo Smalltalk.

Founder of Airflowing (2009–2015), a bootstrapped B2B SaaS for service-company operations.

Currently exploring full-time remote engineering roles at US companies. Brazil-based, fully overlapping with US Eastern hours. Ready to move fast.

Portuguese, Spanish, English

Brasilia (-03:00)

Joined November 2014

EXPERTISE

Rust

3 years experience

REVIEWS FROM CLIENTS

5.0

(26 reviews)

Ilyass Nanaa

October 2016

The meeting was great , very helpful guy , and patient with someone that doesn't have a good basic knowldge with Node.s or terminal and so on. Once again thank you :) i will get back to you as soon as possible .

Dag vB Bunkholt

July 2016

I have used more than a few mentors here, and Sebastian is truly standing out as the mentor that is sincerely interested in helping you, and goes that extra mile. I often come here when I'm in a hurry, and if I can get a hold on to Sebastian I know I can lower my shoulders. It once took all night all weekend, but Sebastian never gave up!

Nobuyuki Fujioka

May 2016

Sebastian is very helpful.

Sebastian Weiss

May 2016

Thanks a lot. He was very helpful. My issue was solved. Sebastian did it! He knows a lot about Meteor and how to debug the code. He also gives me some security hints on how to improve my code. Thanks a lot

John Reynolds

September 2015

He was great. Took the time to understand what needed to be done, then helped me resolve a couple issues along the way to the answer I was looking for. Will look for him again.

Nuvi

September 2015

Sebastian is a really knowledgeable guy with a great personality and learns quickly. He spent some time before our session showing me useful resources to help me get started with my project and showed me best practices with using Meteor, which I thought was really awesome of him. Then he started the session when we were ready to dive into my project request. He has been a great help with pointing me in the right direction and how to go about solving issues as a developer. Definitely recommend 5/5. Thanks again! :)

Chris McNabb

May 2015

Excellent! Great Debugging session!

Anton Loss

March 2015

Excellent mentor, understands what I need very well, and gives fast helpful advice! Expert in Meteor

Andrew Mello

March 2015

One of the best Meteor developers around

Leigh Boone

March 2015

Sebastian was very helpful and gave me best practices as wel as help tacking down my issue

SOCIAL PRESENCE

GitHub

Mapless

Schema-less persistence for Smalltalk with support for multiple backends.

Smalltalk

ride

The Smalltalk web application framework with productivity as a feature.

Smalltalk

Stack Overflow

1764 Reputation

Quick Tips

Run brew cleanup and claim some disk space

I was doing a bit of housekeeping in my MacBook Pro so I can use some additional diskspace. The starting point was to do a scan...

How to evaluate an expression after an AngularJS controller has rendered?

This is a really common need that AngularJS is not providing out of the box. I needed it myself for some projects and you might too? Ok, even if many...

Shutdown a Pharo image using an OS signal

Sometimes you need to control how a worker image starts and stops right from the operative system. You my do it from the terminal but the really important...

EMPLOYMENTS

Senior Software Engineer

Telna

2019-09-01-2023-08-01

Successfully led a team of four in a six-month effort to refactor the main backend code, effectively resolving tech debt issues t...

Successfully led a team of four in a six-month effort to refactor the main backend code, effectively resolving tech debt issues that were impeding containerization.
Developed and successfully implemented a Proof of Concept within 2 days to showcase the migration of the persistence framework from Voyage to Mapless.Achievements
Demonstrated a Rust caching system to extend the main backend capacity, currently above 25Kops and leveraged parts ofthe PoC to continuously expand production capacity beyond 1 Peta Byte in May 2023.
Added a stress testing layer with a custom Golang multithreaded client to produce synthetic traffic that guarantees SLAs.

Python

MongoDB

Bash

Python

MongoDB

Bash

Jira

Test driven development

Docker

Smalltalk

Rust

Docker swarm

Full-stack Software Engineer

Sulvo

2016-05-01-2018-12-01

Lead a team of 6 engineers at Sulvo and designed and implemented the next generation ad server in a JavaScript-based custom stack...

Lead a team of 6 engineers at Sulvo and designed and implemented the next generation ad server in a JavaScript-based custom stack.
Implemented the pipeline to automatically deploy globally acrosss regions using GCloud. Achievements
Implemented an automated deployment pipeline using GCloud, enabling global deployment across regions in a backward compatible way.

Meteor

Cloud

Docker

Meteor

Cloud

Docker

React

Cloudflare

JavaScript

CI/CD

Vue.js

DevOps

AWS

Full-stack Software Engineer

StarterSquad

2015-04-01-2016-08-01

Mentored 2 junior developers from Vandebron.nl in using AngularJS to develop new features for their platform in the energy sector...

Mentored 2 junior developers from Vandebron.nl in using AngularJS to develop new features for their platform in the energy sector. Additionally, I worked with CX teams to complete frontend tasks using both AngularJS and ReactJS, ultimately improving the user experience and completing tasks weekly in a timely and efficient manner.
Developed and published in the AppStore a Swift native app for a client from The Netherlands. Additionally, developed the app's NodeJS backend and Vue dashboard frontend, creating a complete solution.
Developed an MVP for two founders of a dairy industry startup in the Netherlands in one week. The founders were able to secure a Series A funding of €4M in the following 2 months.

Angular

Meteor

JavaScript

Angular

Meteor

JavaScript

Swift

iOS

PROJECTS

MaplessView Project

2014

Schema-less persistence for Smalltalk with support for multiple backends. Ambition Mapless gives you performant state plasticity and hig...

Schema-less persistence for Smalltalk with support for multiple backends. Ambition Mapless gives you performant state plasticity and high availability in a scale that goes beyond one Smalltalk image and without backend vendor locking nor object-mapping impedance mismatch. Supported backends 1. MongoDB 2. Redis 3. Memory 4. PostgreSQL 5. UnQLite 6. SQLite

Smalltalk

MatterView Project

2022

Algorithmically sharded repository for Pharo. Ambition Matter gives you a performant cache of objects with a basic Dictionary API and sc...

Algorithmically sharded repository for Pharo. Ambition Matter gives you a performant cache of objects with a basic Dictionary API and scalable by the number of Pharo images configured in the clients. Features 1. Basic Dictionary API. 2. Simplicity. No transactions, no persistence, just a big cache of Pharo objects. 3. Horizontally scalable by adding nodes to the shard. 4. No need to create and maintain schemas. 5. Homogeneously distributed data load. 6. Fast as a Dictionary can be.

WebSocket

Smalltalk

WebSocket

Smalltalk