# Senior Go Developer - Integration

> Cryptonext Security · Paris, France · Full-time · Posted 2026-11-02

**Workplace:** on_site

**Department:** Research & Development

## Description

## Who we are

CryptoNext Security is a deeptech startup specializing in post-quantum cryptography. Our solutions help businesses and institutions prepare for a future where quantum computers will challenge traditional data security. We work with leading clients in finance, defense, and telecommunications.

## On a daily basis, you will

•     Build and maintain, in Go, the connectors that link CryptoNext Platform to our clients' tools (CLM, CMDB…): extracting, normalizing and exposing data through REST APIs.

•     Consume heterogeneous third-party APIs: handle pagination, rate limits, retries, idempotency and provider outages.

•     Design and evolve the API contracts exposed to CryptoNext Platform: OpenAPI and versioning.

•     Model and query PostgreSQL, use Redis, and process work asynchronously through RabbitMQ.

•     Containerize your deliverables (Dockerfile, Docker Compose) and get your changes through GitLab CI.

•     Instrument your services (logs, metrics, traces), diagnose incidents in staging and production, and contribute to root cause analyses.

•     Write the unit and integration tests that back your features, including against test doubles of provider APIs, and give QA what they need to automate the rest.

•     Review code and help onboard new team members.

•     Work directly with Product and QA.

•     Use AI coding tools as leverage under your own judgement, staying accountable for what lands in the repo.

•     Propose architecture changes and refactorings, and explain the trade-offs you accepted.

## How we work

A team of six engineers, within our 15-person R&D department. Connectors live in a monorepo and follow a hexagonal architecture. Three days a week in our Paris office, the rest remote. Short feedback loops, high standards. We ship a working version early rather than polishing in isolation, and keep solutions as simple as the problem allows.

## Requirements

## The skills you'll need

•     Production Go: concurrency (goroutines, channels), context, explicit error handling, interfaces, modules and standard tooling (go test, go vet).

•     Hexagonal architecture (ports and adapters), or the ability to defend an equivalent split.

•     Third-party API integration: robust HTTP clients, timeouts, retries with backoff, pagination, rate limiting, idempotency.

•     Asynchronous processing: RabbitMQ consumers, acknowledgements, retries and failure handling, dead-lettering, backpressure.

•     PostgreSQL: schema design, migrations and rollbacks, indexing, reading a query plan. Hands-on use of Redis.

•     API contract design: REST, OpenAPI, versioning.

•     Unit and integration testing, with a defensible position on what belongs at which level and on what is worth testing at all.

•     Delivery: Docker and Docker Compose, GitLab CI.

•     Operations: observability and incident diagnosis.

•     Real use of AI-assisted development in a production codebase: agentic workflows, context management, reviewing generated output as critically as a colleague's merge request. You have a view on where these tools pay off and where they create debt.

•     Experience means you can say why you chose an approach, what you rejected, and what it will cost in six months.

## Bonus skills

•     Java.

•     Knowledge of the CLM/PKI (X.509 model) and CMDB domains.

•     Knowledge and hands-on handling of provider authentication schemes: OAuth2, mTLS, API keys.

•     Secure coding practices and application security.

•     Experience in a startup or deeptech environment.

## Benefits

## The team you'll be joining

You will join a team of six engineers who own their features across the whole stack, inside our 15-person R&D department, working closely with Product and QA. You will report to the Head of Engineering and collaborate with other departments to build the backend services and interfaces our clients depend on.

## Our recruitment process

1.   **Initial discussion** with our HR team to explore your background and motivations.

2.   **Technical interview** with a developer: a live coding session of 1 to 1.5 hours. AI coding tools are required, not merely allowed. We are interested in how you direct and review them. No take-home assignment.

3.   **Meeting with a manager** to ensure alignment with our company culture.

4.   If successful, you'll receive a final offer!

## Benefits

## What's in it for you at CryptoNext

•     A stimulating work environment with cutting-edge technological challenges.

•     A competitive salary, aligned with our compensation philosophy.

•     A deep dive into the exciting world of post-quantum cryptography and cybersecurity.

## Apply

[Apply at Cryptonext Security](https://apply.workable.com/cryptonext-security/j/6B28B604E1/apply)

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