Executive summary
After big organizational changes, Gumtree needed to regain their independence and that meant re-establishing their ecommerce service platform without disruptions to its millions of users.
Helmes joined as a strategic advisor and engineering partner. Together with Gumtree engineers and business owners, we executed a seamless migration to Google Cloud Platform (GCP); re-architected core marketplace services; delivered new native mobile applications and introduced reliability practices that keeps incident counts low. All of this resulted in cutting down the annual cloud infrastructure spend by more than € 1.1 million.
“Helmes turned our business carve-out into a growth opportunity – acting as our trusted advisor and delivery partner,” comments Mal Minhas, The Chief Product and Technology Officer.
Meet the customer
Gumtree is the leading of two-sided classifieds platform in United Kingdom. Driven by its “Good Finds” ethos, the marketplace lets people browse everything from cars to vintage sofas via its web and mobile apps, making local buying and selling simple, enjoyable and affordable.
Championing recommerce, Gumtree aims for “a world where we share more and waste less” and offers a carbon-savings calculator that shows the CO₂ avoided when shoppers choose second-hand.
The challenges
It’s a project that came with its fair share of challenges:
# Carve-out deadline: Gumtree had to leave its former owner’s infrastructure quickly, without any room for prolonged downtimes.
# Legacy stack: monolithic architecture and on-prem data services, limited performance and inflated costs needed tackling
# User-driven mobile innovation: users demanded faster, better and more stable iOS/Android apps.
# Operational resilience: the rebuild offered a perfect opportunity to adopt a uniform approach to monitoring, incident response and continuous optimisation.
Our approach
We chose a tested and proven approach to turn challenges into opportunities:
- High-performing, dedicated team
Cloud architects, back-end and mobile engineers, SRE specialists, UX, and delivery leads worked side-by-side with Gumtree staff on a single backlog and shared KPIs. - Advisor-plus-builder model
Helmes provided advisory (migration run-books, cost models) and hands-on execution (coding, DevOps, release management). - Reliability & optimisation loop
Every service shipped with dashboards, alerts, and cost-visibility to keep incidents low and spending under control.
The solution
The project started with cloud migration:
- Landing zone: secure GCP foundation with network, IAM, and compliance guard-rails.
- Service move: marketplace workloads containerised and deployed on Google Kubernetes Engine (GKE); on-premises Kafka cluster to Confluent Cloud migration.
- Data layer: on-prem databases → Cloud SQL; DataBricks→ BigQuery.
- CI/CD: Terraform / Atlantis, GitHub Actions, Jenkins, Spinnaker for automated, repeatable releases.
The cut-over – with all of its complexity – was completed on schedule with no critical user impact.
Platform optimisation & mobile delivery phases included:
- Gradual move from monolith to micro-services improved scalability and simplified maintenance.
- Code clean-up and GKE right-sizing delivered; ElasticSearch cluster usage optimization (reduction of number of requests to ES, ES cluster setup optimization).
- Storage optimization: a purge of ~ 250 million obsolete images from Cloudflare; source data format unification; lifecycle policies implementation; SQL optimization and impact analysis implementation.
- Launched new iOS/Android apps with an enhanced user experience.
“Helmes has been more than just a development partner.”
Agathe Merat, Head of Delivery
The results
Achieved technological independence: a cloud native platform with all workloads running on Gumtree’s own GCP environment.
Saving 1.1+ million euros each year through improved performance, reduction of incidents and lower data storage and automation (with automated PII scanning and masking via Google Cloud DLP).
Stable operations: production incidents minimised compared to the pre-migration state; improved monitoring and alerting and up to 5x performance increase for incremental batch runs and partial backfills.
Improved user experience through native apps that complement the upgraded online marketplace (ecommerce 3P).
“They successfully migrated our services to GCP, relentlessly optimised the cloud bill to provide significant gains, kept maintenance windows invisible to users, and co-developed new platform capabilities that keep us ahead,” confirms Mal Minhas, Chief Product and Technology Officer from Gumtree.
Helmes remains Gumtree’s trusted advisor and delivery partner, providing dedicated engineering capacity for new marketplace features; ongoing reliability & cost-optimisation reviews; and collaborative roadmap workshops to keep Gumtree’s platform ahead of user expectations.
“Helmes has been more than just a development partner. From the very beginning, they took the time to understand our needs and quickly became a trusted part of our day-to-day operations. Their support during some of our most challenging periods has been invaluable. Whether it was tight deadlines or shifting priorities, they remained flexible, committed, and dependable. Working in a close time zone made things easier, but it’s their dedication and integrity that made the real difference,” adds Agathe Merat, Head of Delivery
Technologies
Application development: Java • Python
Infrastructure, Cloud & DevOps: GCP • GKE • BigQuery • Bigtable • Cloud Run • Cloud SQL • Confluent Kafka Cloud • Elastic Cloud • Terraform/Atlantis • GitHub Actions • Jenkins • Spinnaker •
Data tools: Airbyte • Dataflow • Datastream • Airflow
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