Freelance API Designer / Business Analyst

Blu; Barcelona; Hybrid; EUR 60,000 - 90,000; Full time

Job summary

Blu in Barcelona is seeking an API Designer & Business Analyst to standardize API architecture and ensure secure, scalable endpoints across global teams.

You will draft OpenAPI specs, review PRs in Azure DevOps, participate in the API Design Authority, and help evolve tooling and CI/CD for smooth integrations.

This on-site/hybrid role offers collaboration with cross-functional groups, English-focused teamwork, and a path to influencing architectural standards across international projects.

Qualifications

• Minimum 5 years of API design and business analysis experience.
• Strong backend tech stack experience with .NET 8.0 and ASP.NET Core.
• Experience with OpenAPI/Swagger and RESTful design patterns.
• Proficient Git version control and Azure DevOps workflows.
• Knowledge of secure coding principles and cloud deployments.
• Fluent English and experience in Agile teams.

Responsibilities

• Review business requirements and translate into robust API models.
• Draft OpenAPI 3.x specifications and Swagger documentation.
• Create and review Pull Requests in Azure DevOps to validate implementations.
• Contribute to API Design Authority and promote best practices.
• Improve internal tooling, CI/CD, and integration processes.
• Support internal and partner integrations to resolve blockers.

Skills

API design

Business analysis

.NET 8.0 / ASP.NET Core

xUnit testing

Git / VCS

Azure Cloud

PowerShell

DevOps pipelines

RESTful services

Agile teamwork

English proficiency

Tools

Swagger Hub

OpenAPI 3.x

Postman

Job description

• Location & Work Model: Barcelona (On-site / Hybrid context depending on project setup)
• The Highlight: Modernizing Global Insurance Tech

What's the Project?

Imagine working behind the scenes for one of the largest global leaders in insurance and assistance services. This sector thrives on protecting people, businesses, and assets around the globe-which means handling millions of secure transactions daily.

To keep up with that scale, the business is continuous upgrading its digital ecosystem, transitioning legacy platforms toward cloud-native architectures, and streamlining integration across international entities. You will step into a high-impact environment where clean architecture and smooth system-to-system communication keep millions of users connected without a hitch.

And Your Role in This?

As an API Designer & Business Analyst, you bridge the gap between complex business requirements and high-performance technical design. Your core objective is to define, standardize, and elevate API architecture across cross-functional teams, ensuring every end-point built is secure, scalable, and fully aligned with organizational standards.

More specifically, you will:

• Review and challenge incoming business requirements to ensure they translate into efficient, well-structured API models.
• Draft specifications using OpenAPI 3.x and Swagger standards to guide developers accurately.
• Create and review Pull Requests in Azure DevOps while making sure real code implementations match original API designs.
• Serve as an active member of the internal API Design Authority, sharing best practices and evangelizing modern standards across developer groups.
• Help refine internal tooling, workflows, and continuous integration practices to keep tech operations smooth.
• Support internal teams and external business partners during integration phases to resolve roadblocks swiftly.

Ok, What Should You Bring?

We are looking for someone with a strong blend of API governance experience and sharp software engineering roots. Here is what makes a great match:

The Non-Negotiables (Must-Haves)

• A minimum of 5 years of hands-on experience focused on API design and business analysis.
• Deep technical familiarity with .NET 8.0 and ASP.NET Core, alongside robust unit testing practices using xUnit.
• Proven command of version control using Git, including advanced capabilities like history rewriting.
• Practical knowledge of Azure cloud services, PowerShell automation, and DevOps delivery pipelines.
• Demonstrated application of secure coding principles and RESTful standards (Richardson Maturity Levels 2 and 3).
• Professional fluency in English, paired with experience working in Agile team environments.

The Nice-to-Haves (Bonus Points)

• Proficiency in API specification tools such as Swagger Hub, OpenAPI 3.x, and Postman.
• Comfort with visual modeling techniques like UML sequence diagrams or MindMaps (XMind).
• Hands-on familiarity with production monitoring, incident response, or multi-cloud concepts across AWS and OpenShift.

Is That It?

Not quite! This role gives you direct influence over the foundational design patterns used by international development teams, making it an ideal step for someone who loves both technical craftsmanship and high-level strategy.

• Target: Establish reliable, secure, and clear API specifications that reduce development cycles and prevent integration friction.
• Salary & Package: Starting at €[Insert Specific Amount] gross annually, tailored to experience, alongside standard local benefits.
• The Vibe: Collaborative, structured, and innovation-minded, with zero business travel required so you can focus on building great systems.