Senior Fullstack Developer (PHP + React)

About the role

SINGU is a fast-growing PropTech company building a CAFM platform for warehouse, logistics, retail and multi-site commercial real estate, with over 250 million m² of property managed worldwide. The Technical Account Management (TAM) team delivers customizations, dedicated functionality and system integrations for its largest enterprise clients, including Prologis, P3, CTP and AmRest. The role is based in Cracow and involves data imports/exports and integrations with external systems (ERP, HR, finance, SSO), where security, data correctness and database performance are critical.

Key responsibilities

• Design and implement integrations and custom functionality for enterprise clients
• Build secure, high-performance backend services in PHP and extend React frontends when needed
• Design and optimize data import/export processes with a focus on security, data integrity and performance
• Find and remove performance bottlenecks in application and database layers
• Take part in technical breakdown and estimation, and co-own API contracts
• Review code and mentor mid-level developers; act as the go-to person for backend and database topics
• Collaborate with the Tech Lead, QA and other SINGU teams (Platform, Core)

Required profile

• 5+ years of commercial PHP backend development (7.4+/8)
• Proven experience designing and maintaining REST APIs
• Hands-on experience with data import pipelines and external system integrations (files, APIs, queues), including idempotency, validation, error handling and reprocessing
• Strong focus on security, performance of high-volume operations and full ownership of delivered solutions
• Experience mentoring developers and doing meaningful code reviews
• Active use of AI tools (Claude, Cursor, Copilot, ChatGPT) in daily work
• Communicative English (B2+); fluent Polish, as the team works in Polish internally

Required skills

• Expert PostgreSQL: query optimization, indexing, execution plans, migrations on large datasets
• Working React knowledge, able to deliver a feature end-to-end when needed
• Nice to have: Phalcon, PostgreSQL tuning (partitioning, vacuum, planner), ERP integrations (SAP, Dynamics, PeopleSoft), SSO (SAML/OIDC), Docker, AWS, CI/CD, multi-tenant B2B SaaS background, test automation improvements