About the Position

Principal Software Engineer

Work Mode: Hybrid

Job Type: Full Time

Location: Barcelona, Spain

Base Salary: €75.000 - 85.000

The Company

We are partnering with an established and profitable travel-technology company that uses proprietary AI and APIs to automate complex operational processes for airlines and travel agencies.

Its large-scale, multi-tenant platform processes business-critical transactions where financial correctness, reliability, and traceability are essential. As the company continues to grow, it is strengthening its engineering practice and evolving the software and data architecture behind its core products.

The Opportunity

We are looking for a hands-on Principal Software Engineer to take ownership of the architectural direction of the core services and data layer behind a mission-critical transaction platform.

This is a senior individual-contributor role without direct reports, but with significant influence across multiple engineering teams. You will define clearer domain and module boundaries, make pragmatic decisions about monoliths and services, and translate business priorities into technical choices that teams can implement.

The company is not looking for someone to arrive with a predetermined transformation plan or propose an immediate rewrite. The priority is to understand the existing environment, identify where complexity is creating genuine business or operational problems, and improve the architecture incrementally while active product development continues.

You will work closely with the SVP of Engineering and Director of Platform. Infrastructure and operational delivery already have established ownership, allowing you to focus primarily on software, domain, and data architecture while remaining close to implementation and production.

Responsibilities

Define and evolve the architecture of core services, business domains, and data platforms.
Establish clear module, bounded-context, API, and ownership boundaries across the product.
Review previous migrations and determine when systems should be modularized, refactored, retained, consolidated, or replaced.
Reduce accumulated technical complexity without disrupting ongoing product delivery.
Design distributed and event-driven services with explicit consistency, recovery, and failure-handling models.
Embed financial-integrity patterns such as idempotency, reconciliation, validation controls, audit trails, and end-to-end traceability.
Shape operational and analytical data architecture, including data contracts, movement, quality, and downstream usability.
Lead architecture reviews and document important decisions through technical designs and Architecture Decision Records.
Work with product and engineering leaders to balance correctness, delivery speed, operational risk, cost, and commercial priorities.
Mentor experienced engineers through design reviews, pairing, and hands-on technical coaching.
Contribute directly to production code, testing, debugging, and delivery when your involvement adds value.

Requirements

Essential Experience

At least eight years of professional software engineering experience, including substantial responsibility as a Principal, Staff, or Lead-level individual contributor.
Strong experience designing backend services and application or domain architecture in complex production environments.
Evidence of architectural decisions that you personally owned across multiple teams, services, or business domains.
The ability to define domain, module, and service boundaries and make proportionate monolith-versus-microservices decisions.
Experience simplifying or incrementally modernizing existing systems rather than defaulting to large-scale rewrites.
Experience in payments, fintech, travel technology, or another transaction-sensitive environment where software errors can cause financial loss or customer harm.
A strong understanding of financial-integrity principles, including idempotency, reconciliation, auditability, validation, and transaction traceability.
Experience building distributed, event-driven, or high-volume transactional systems.
Experience shaping data architecture for operational and analytical use cases beyond database administration.
Strong knowledge of relational data modeling, consistency, schema evolution, and transaction boundaries.
A record of leading cross-team technical initiatives and influencing experienced engineers without relying on direct authority.
The ability to connect architecture with product priorities, operational risk, cost, and measurable business outcomes.
A hands-on mindset and willingness to contribute to production code, tests, and technical documentation.

Particularly Relevant Experience

Domain-Driven Design, bounded contexts, CQRS, event sourcing, or comparable domain-modelling approaches.
Travel-industry systems such as GDS integrations, BSP or ARC settlement, ticketing, refunds, or Agency Debit Memos.
Payment rails, ledgers, card networks, settlement, reconciliation, fraud controls, or regulated financial workflows.
Kafka or similar event-streaming technologies, including their consistency and delivery trade-offs.
Multi-tenant SaaS platforms where tenant isolation and data correctness are critical.
AWS or GCP, Kubernetes, observability, and modern software-delivery practices.
Direct involvement in major customer-impacting incidents and the systemic improvements that followed.
Contract testing, property-based testing, or invariant-driven testing for critical business logic.

Current Technical Environment

The current environment includes:

TypeScript
PostgreSQL
Cloudbase
Datadog
Serverless components
A combination of monolithic applications and independent services
AWS and GCP
GitHub
ArgoCD

Direct production experience with every technology is not required. The company is open to experienced engineers from other language ecosystems who can adapt while contributing at Principal level.

We Offer

Take meaningful ownership of the architecture behind a business-critical transaction platform.
Solve complex software, domain, data, and distributed-systems problems with direct commercial impact.
Influence technical direction across several engineering teams while remaining hands-on.
Work closely with experienced engineering and platform leaders.
Help simplify an established platform without being expected to pursue another disruptive transformation.
Join a profitable, growing technology company serving major organizations within the international travel industry.
Contribute to an engineering culture centered on reliability, clarity, and continuous improvement.

Interview Process

The selection process consists of five stages:

An exploratory conversation with the SVP of Engineering.
A business-focused conversation with the VP of Operations.
A technical deep dive with the SVP of Engineering and Senior Engineering Director.
A combined business and technical case, followed by a presentation and discussion.
A final business conversation with the relevant Business Unit Manager.

Why Join?

If you are a senior engineer who enjoys untangling complex systems, making practical architectural decisions, and helping multiple teams deliver more effectively, we would be happy to speak with you.

Apply directly or contact [email protected] for a confidential conversation.

Apply for this Position

Full Name *

Email *

Phone *

Upload CV/Resume *Allowed Type(s):.pdf,.doc,.docx

By using this form you agree with the storage and handling of your data by Tech StaQ *

TECH STAQ

C/Calabria 52

08015 Barcelona

Fred. Roeskestraat 115 1076 EE Amsterdam

+34 666 685 336

[email protected]

• ABOUT US

• CONTACT US

• JOBS

• HIRING DIAGNOSTIC

• RESOURCES

• EOR - Hire in Spain

Privacy PolicyTerms of Service

Principal Software Engineer

Job description