Senior Backend Developer

Synergy Codes; Wrocław; Hybrid; PLN 180,000 - 260,000; Full time

Job summary

Synergy Codes is seeking a senior backend engineer to grow the Workflow Builder backend and its durable workflow engine. You will own modules end to end from design through deployment to production support.

You will deploy the product at customers, connect it to their systems, and work hands-on with the team to move from decision to production quickly. This is a senior role with a direct impact on customer environments.

Qualifications

• Strong TypeScript and Node.js with production backend experience.
• Production experience with Temporal or another durable execution engine.
• Clear grasp of determinism, replay, retries, durable timers, and resumptions in flight processes.
• Idempotency, deduplication, partial failure handling, and workflow dependencies.
• Systems design for horizontal scaling of workers in Temporal or similar engines.
• PostgreSQL at high data volumes: tuning, indexes, partitions, transactions.
• Hands-on with Redis or similar systems, including cache and TTL handling.
• Deploying and running apps on Azure or AWS and ability to work in the other.
• REST APIs, webhooks, authentication, data isolation, and secrets management.
• Docker, CI/CD, integration and load tests, monitoring, and failure diagnosis.
• Experience with AI agents in implementation, tests, or code analysis.
• English at C1 level.

Responsibilities

• Develop the product backend and API for workflow graphs.
• Build and grow integrations with external systems.
• Run customer deployments and connect Product to customer systems.
• Scale workers and improve performance and reliability.
• Design modules, write tests, diagnose production issues, and review code.

Skills

TypeScript

Node.js

Durable execution

English (C1)

Security and data isolation

Tools

Temporal

PostgreSQL

Redis

Docker

Kubernetes

Terraform

OpenTelemetry

AWS

Azure

Job description

We are looking for a senior engineer to grow the backend and the workflow engine behind Workflow Builder, and to take the product into customer environments. You own modules end to end, from design through deployment to production support.

About this job opening

We build Workflow Builder , our product for designing and running processes visually. It gives automation platforms a workflow editor on the front end and a durable execution engine underneath.

You will grow that backend and workflow engine, deploy the product at customers, and connect it to their systems.

This is a hands-on senior role with a short path from decision to production.

What you will do

• Develop the product backend, the API, and the mechanics that execute workflow graphs.
• Build and grow integrations with external systems.
• Run customer deployments and connect the product to customer systems.
• Scale workers and improve the performance and reliability of running processes.
• Design modules, write tests, diagnose production issues, and review code.

What we expect

Must have:

• Strong TypeScript and Node.js, with production experience building backends.
• Production experience with Temporal or another durable execution engine, and readiness to work with Temporal.
• A clear grasp of determinism and replay, retries, durable timers, and resumptions. You can safely change code that handles processes already in flight.
• Idempotency, deduplication, partial failure handling, and compensation. You understand dependencies between steps and parallel workflow branches.
• Designing and shipping systems that scale. Horizontal scaling of workers in Temporal or a similar engine, concurrency control, and removing bottlenecks.
• PostgreSQL at high data volumes: query tuning, indexes, partitioning, transactions, and migrations.
• Hands‑on work with Redis or similar systems, including cache, TTL, invalidation, and data consistency.
• Deploying and running applications on Azure or AWS. You know one of them and are ready to work in the other.
• REST APIs, webhooks, and SSE (server-sent events). Authentication, permissions, customer data isolation, and secrets management.
• Docker, CI/CD, integration and load tests, monitoring, and failure diagnosis.
• Experience working with AI agents on implementation, tests, or code analysis. You review their changes and want to keep working this way.
• English at C1 level.

Nice to have:

• React and React Flow.
• Temporal TypeScript SDK.
• Kubernetes, Terraform, and OpenTelemetry.

How you work with us

• You run tasks on your own, from design through deployment to maintenance.
• You agree on requirements with the customer and the team. You flag risks and blockers, and bring solutions with them.
• You share knowledge, take part in code reviews, and act on feedback.
• You discuss technical solutions with customers in English.

Work model: remote or hybrid. Our office is in Wroclaw if you like working on site.

Your next great workspace goes beyond just a job

The conversation lasts about 2 hours. It is a bit long, but we don’t have more interviews, follow‑ups, or homework assignments. We try to ensure a friendly, informal atmosphere to reduce stress. You don’t need to worry.