Florent Espanet, Developer in Lyon, France
Florent is available for hire
Hire Florent

Florent Espanet

Verified Expert  in Engineering

Back-end Developer

Lyon, France
Toptal Member Since
September 22, 2022

Florent is a back-end engineer with ten years of experience designing and building highly scalable products. He worked for Datadog and two French startups that became unicorns, LumApps and Back Market, and led a team of 15 back-end engineers. Florent is a polyglot (Python, Go, Java) specializing in distributed services deployed on AWS or GCP using Kubernetes.


Java, Go, Python, Apache Kafka, RocksDB, SQL, Redis, Distributed Architecture...
Back Market
Python 3, Linux, Kubernetes, Docker, FastAPI, Django, Django ORM, SQLAlchemy...
Python, Google Cloud Platform (GCP), Interviewing, Message Queues...




Preferred Environment

Python, Go, Java

The most amazing...

...thing I've made is a Pub/Sub Python library used by tens of services to publish and consume millions of messages per day.

Work Experience

Senior Software Engineer

2023 - PRESENT
  • Developed a highly reliable service consuming millions of messages per hour from a Kafka topic. This service factorizes some logic that was duplicated on four services and, at the same time, improves performance, reliability, and observability.
  • Developed the API of the entry point to every security product at Datadog. The API aggregates data from several sources and allows the presentation of all security issues in a customer's environment.
  • Improved the development tooling by adding a staging environment to the team's main service and the automation, documentation, and tooling required for every teammate to use it.
Technologies: Java, Go, Python, Apache Kafka, RocksDB, SQL, Redis, Distributed Architecture, Terraform, Datadog, Infrastructure as Code (IaC), Amazon Web Services (AWS), Google Cloud Platform (GCP), Kubernetes, Docker, Back-end, Architecture

Senior Back-end Engineer

2019 - 2023
Back Market
  • Played a key role in Python and Django upgrades and overall performance and CI/CD improvements.
  • Designed and developed a library that enabled all back market back-end services to communicate asynchronously by publishing and consuming messages on RabbitMQ queues.
  • Extracted a domain from a Django monolith in a dedicated service. Designed and executed the migration plan and created and implemented the service itself.
  • Designed and developed an SDK generator for all services that defined a standard way to consume APIs through a tested and type-checked interface.
Technologies: Python 3, Linux, Kubernetes, Docker, FastAPI, Django, Django ORM, SQLAlchemy, Celery, Kombu, Pytest, Poetry, Terraform, Terragrunt, Amazon Web Services (AWS), Amazon SageMaker, OpenAPI, Swagger, REST APIs, Jira, GitHub, CircleCI, Travis CI, RabbitMQ, Emacs, Datadog, PostgreSQL, MySQL, Redis, Infrastructure as Code (IaC), APIs, Architecture, Web Architecture, Web Application Architecture, Back-end, SQL, Amazon S3 (AWS S3), Apache Kafka, Distributed Architecture

Lead Back-end Engineer and Engineering Manager

2015 - 2019
  • Developed an entire notification system in a very short time to sign a big client, Google.
  • Designed the migration of the monolith to microservices architecture.
  • Grew the back-end team from three to 15 people by creating job ads, collaborating with external tech recruiting companies, and organizing tech and fit interviews.
  • Designed and implemented an email-sending service that sent more than 100,000 emails a day.
Technologies: Python, Google Cloud Platform (GCP), Interviewing, Message Queues, Performance Analysis, Key Performance Indicators (KPIs), MongoDB, Docker, Kubernetes, Swagger, REST APIs, Linux, Emacs, Python 3, PostgreSQL, MySQL, Amazon Web Services (AWS), Amazon EC2, APIs, Architecture, Web Architecture, Web Application Architecture, SQL

Lead Back-end Engineer

2014 - 2015
Like a Bird
  • Developed a new Twitter contest mechanics end-to-end as the company's only developer, including performing server administration tasks, designing a database, and building back end and front end.
  • Reworked the whole infrastructure architecture to enable scaling, from a single EC2 server to load balancing with auto-scaling and messages queues consumed by background workers.
  • Collaborated hand-in-hand with the CEO and COO to design new Twitter contest mechanics.
  • Handled customer care by phone and email to understand the client's needs and issues.
  • Teamed with the CEO to raise a seed round with investors. Prepared and presented the financial numbers and forecasts to potential investors.
Technologies: Amazon Web Services (AWS), Symfony, PHP, Python, JavaScript, AngularJS, Linux, Git, Celery, Docker, MySQL, SQL, Amazon S3 (AWS S3)

Personal Financial Advisor As A Service

A personal financial advisor as a service. Customers are matched with a financial advisor and can talk with them through WhatsApp against a monthly fee. I was tasked with the whole back end of this small startup. I used mainly Go and PostgreSQL to write FastAPI, Whatsapp webhooks, and Stripe webhooks.

SDK Generator

An SDK generator based on an OpenAPI generator implements Back Market standards and a complete continuous deployment pipeline to simplify developers' lives. The SDKs are generated on API contract updates and published to a Python package repository. They are deeply integrated with Datadog (logs, metrics, and traces) and the Back Market pipeline.

Pub/Sub Python Library

A Pub/Sub Python library that handles asynchronous communication between microservices at Back Market. The library helps publish and consume messages with an easy-to-learn interface in a robust way. It implements industry standards such as CloudEvents.io to describe events and enforces standards specific to Back Market. It provides particular bindings for popular web frameworks such as Django, Flask, or FastAPI to ease the integration with existing services.


Django ORM, SQLAlchemy, Kombu, OpenAPI, REST APIs, WhatsApp API, Terragrunt, Stripe API


Emacs, Celery, Pytest, GitHub, CircleCI, RabbitMQ, Git, PyPI, Terraform, Travis CI, Amazon SageMaker, Jira


Django, Swagger, Flask, Symfony, AngularJS


Python 3, Python, SQL, Go, Java, PHP, JavaScript


Web Architecture, Web Application Architecture


Linux, Docker, Kubernetes, Google Cloud Platform (GCP), Amazon Web Services (AWS), Amazon EC2, Apache Kafka


Datadog, Amazon S3 (AWS S3), MySQL, PostgreSQL, Redis, RocksDB, Polyglot Persistence, MongoDB


FastAPI, Poetry, Interviewing, Message Queues, CI/CD Pipelines, APIs, Back-end, Distributed Architecture, Infrastructure as Code (IaC), Supabase, Performance Analysis, Key Performance Indicators (KPIs), Architecture, Minimum Viable Product (MVP), Security Product Development

Collaboration That Works

How to Work with Toptal

Toptal matches you directly with global industry experts from our network in hours—not weeks or months.


Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.

Start your risk-free talent trial

Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.

Top talent is in high demand.

Start hiring