Senior Go Developer - Integration

Cryptonext Security; Paris; Híbrido; EUR 70.000 - 110.000; Jornada completa

Ventajas ofrecidas por este puesto de trabajo

Hybrid work

Competitive salary

Deeptech startup environment

Descripción de la vacante

CryptoNext Security SAS is hiring a Go backend engineer to build and maintain connectors that link CryptoNext Platform to client tools via REST APIs. You will consume heterogeneous third‑party APIs, design API contracts, model data in PostgreSQL, and use Redis and RabbitMQ for asynchronous processing.

Dockerize your services and maintain CI pipelines, with a strong focus on observability and code quality. You will collaborate with Product and QA, review code, and leverage AI-assisted development

Formación

• Proven Go backend development experience in production systems.
• Strong understanding of hexagonal architecture and ports/adapters.
• Experience integrating with diverse third‑party APIs and handling retries, pagination and idempotency.
• Solid knowledge of PostgreSQL schema, migrations, indexing and query optimization.
• Familiarity with Redis, message queues, and asynchronous processing with RabbitMQ.
• Experience containerizing services with Docker and deploying via GitLab CI.

Responsabilidades

• Build and maintain Go connectors linking CryptoNext Platform to client tools (CLM, CMDB) via REST APIs.
• Consume heterogeneous third‑party APIs with pagination, rate limits, retries, and outages.
• Design and evolve API contracts (OpenAPI and versioning).
• Model and query PostgreSQL; use Redis; process tasks asynchronously with RabbitMQ.
• Containerize deliverables with Docker/Docker Compose and integrate with GitLab CI.
• Instrument services with logs, metrics, traces; diagnose incidents in staging/production; perform RCAs.

Conocimientos

Go

Hexagonal architecture

API integration

PostgreSQL

Redis

RabbitMQ

Docker

OpenAPI

REST

GitLab CI

Testing (unit/integration)

Code reviews

Herramientas

PostgreSQL

Redis

RabbitMQ

Docker

GitLab CI

OpenAPI

Descripción del empleo

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.

• 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.

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

• 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.

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.