Barcelona, Spain · Full-time · Fully office-based€65,000–€85,000 gross per yearCandidates must already be based in Barcelona.
Visa sponsorship is not available.
Migma is building an AI platform that creates and sends on-brand email campaigns end to end.
We are a two-person founding team in Barcelona, hiring a backend engineer with strong Node.Js and MongoDB experience who has shipped AI features in production.
What you will do Build and maintain Node.Js services and APIs.
Improve MongoDB queries, indexes, and data models.
Develop AI generation workflows and improve the quality and consistency of their outputs.
Add useful monitoring and tests around critical workflows.
Build product integrations and improve backend performance and reliability.




What we need Strong experience running Node.Js backends in production.
Practical MongoDB knowledge, including query performance, indexing, and data architecture.
Ability to explain how you measure AI output quality, latency, reliability, and cost.
Our stack Node.Js, Express, MongoDB, Redis, BullMQ, and Python tooling; The product frontend uses Next.Js, React, and TypeScript.
Useful extras Python services, structured LLM outputs, evaluations, agent workflows, or design-to-code generation.
Stripe webhooks and idempotency, AWS SES and email delivery, or real-time systems.
Shopify or Figma integrations, HTML email, React Email, or MJML.

📌 Senior Backend (España)
🏢 Migma
📍 España