Back-end Developer Golang (H/F/NB)

Permanent contract
Paris
Salary: Not specified
Starting date: August 31, 2025
A few days at home

Ipsos
Ipsos

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Questions and answers about the job

The position

Job description

Company Description

At Synthesio, we transform 80 million daily social posts into actionable insights for global brands like Michelin, Renault, Sanofi, and many others, thanks to our real-time AI stack.

We, Ipsos Synthesio, are a leading marketing SAAS company. Our technology allows global brands to make business decisions based on online consumer feedback. We centralize public data from many providers, such as posts on social networks, press articles, forums, search data and more. After the collection phase, we enrich it through AI models and provide intelligence in many visualizations and APIs.

You want to join a deep tech and growing company with at-scale generative artificial intelligence applications, we are hiring candidates!

Lastly, at Synthesio, we have a strong tech culture. This means the teams have an important role. Each squad is empowered, owns together the success of the projects, and chooses their deliverables and their timelines.

Our department

The Synthesio product engineering department is focused on data provisioning, enrichment, and exploitation.

Synthesio crawls numerous public consumer data footprints including social, reviews and ratings, survey, search, and press data, representing more than 80M new documents per day. Each document is then analyzed and enriched using custom NLP and image recognition models developed by our data scientists. All this data is stored in databases and can be accessed by our customers via our dashboarding solution or our APIs.

Job Description

As a member of the back-end team, you will:

  • Be a full-time member of a squad

  • Maintain processing pipelines of 80 M documents ingested per day and 100 billion in storage

  • Design solutions for squad projects, in collaboration with the product owner and the other back-end/front-end/machine-learning developers of the squad

  • Develop and implement these projects

  • Define milestones for project implementation and deployment

  • Evolve and maintain the tools and libraries shared by the back-end team

Our back-end stack: Go, Python, JS, React, MySQL, Elasticsearch, Cassandra, Kafka, Gitlab, Docker, Ansible.

Our platform uses a microservice architecture containing 200+ microservices, most of them written in Go and using Kafka or HTTP to communicate.

The hardware infrastructure is composed of hundreds of rented bare metal servers running Debian. A big part of it is dedicated to storage, including:

1 PB+ Elasticsearch, 750TB+ MySQL clusters, 150 TB+ Scylla DB, and 250TB+ of Kafka.

Example projects we’ve worked on:

  • Add vector search capabilities.

  • Data usage tracking to enable cost monitoring and tailored billing.

  • Implement new crawlers to retrieve documents from more diverse sources.

  • Revamp of the alerting system for increased stability and additional functionalities.

  • Custom AI enrichments for clients to further personalize their experience and usage.


Preferred experience

Preferred Experience :

  • Experience with complex microservice architecture is preferred

  • Knowledge of Golang is beneficial but not required

  • Interest in system performance and robustness

  • Prior experience with very large amounts of data, message queues and high-throughput processing

Soft Skills :

  • Rigor and strong appetite for software quality

  • Interest in manipulating dozens of microservices in data processing pipelines handling billions of documents

  • Curiosity and passion to discuss the consequences of a design choice

  • Good communicator, self-starter, and collaborative enthusiast

  • Interested in understanding user needs

  • Independent, self-organizing, and able to prioritize multiple complex assignments

  • Represent the organization and advocate its technological efforts and capabilities using external presentations and publications

  • Interested in multicultural companies

  • Fluent in French and English in writing, speaking, and reading


Recruitment process

  • A 30-minute screening phone call with a Back-end Manager 

  • A 60–90-minute interview with some engineers of the team (video call possible) 

  • A 2-hour live coding interview, where you will be asked to create a program that solves a (mostly realistic) problem (so no need to cram algorithms!), in the language of your choice (Video call possible) 

  • Optional meet & greet (30 minute each) with various members of the team (Product Managers, Site Reliability Engineers, and Front-end engineers…) (video call possible) 

  • Proposal

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