Apache Cassandra Experts in Berlin
matched in minutes by AIHire experts who design distributed data models, tune Cassandra clusters and connect applications through Java, Python or Kubernetes. FRATCH matches you quickly and precisely with vetted, available freelancers who fit your project.
Meet FRATCH Experts in Berlin, who have recently used Apache Cassandra
Domenic V.
Last position:
Founder at VOS Ventures Tech UG
Working as independent / interim / fractional CTO / engineering director, technical leader, builder, coach. Select achievements:
- Fractional CTO for a music-tech startup. Helped unlock further funding by providing the technical strategy and plan behind their vision and pitch deck, then executed it: vision to a working beta, 0 to 1, on time and on budget against that plan.
- AI automation for a compliance business. An annual research process — days of a person working through spreadsheets and checking websites by hand, so costly it had been abandoned for years — now runs automatically every month and takes about an hour to review. Stale or missing data became current data, twelve times a year.
- An AI development autopilot. Agents take an approved ticket, implement test-first, verify against a running system and open a pull request. An AI committee reviews on various categories and provides risk assessments based on my specs. Nothing merges without a human.
- Coaching and sparring for engineering leaders. Developing engineering managers was most of my job as a director; I now do it one to one.
Wolfram K.
Last position:
AI / Machine Learning Engineer (Projects & Applied AI) at UNIVERSITÉ PARIS 1 PANTHEON-SORBONNE & LIORA
- Designed and implemented a hybrid recommendation system (content-based + collaborative filtering)
- Built end-to-end ML pipelines including data processing, feature engineering, model training, and evaluation
- Developed RAG-based LLM systems using LangChain and vector databases for semantic search and knowledge retrieval
- Established MLOps workflows with MLflow for experiment tracking, versioning, and deployment readiness
- Implemented deep learning models (computer vision & classification) using PyTorch and TensorFlow
Ola V.
Last position:
IT Lecturer
- IT training in theory and practice for IT specialists in application development and system integration
Nune I.
Last position:
Fractional CTO at OpsWorker
OpsWorker turns Kubernetes alerts into root-cause analyses, on top of the monitoring a team already runs. I lead the technical side: the agent architecture, the AWS infrastructure it runs on (fully inside EU regions), and the engineering decisions behind it, read-only in the cluster by default, human in the loop for judgment. The stack underneath: Amazon Bedrock and Bedrock AgentCore, agents built with the Strands Agents SDK, the Claude and OpenAI APIs, and the Kubernetes API.
Qaiser A.
Last position:
Freelance Lead DevOps Engineer at Schwarz Gruppe Produktion
Bootstrapping a CloudOps team and building a multi-cloud provider backend for a low-code Internal Developer Platform (IDP) with env zero
Introducing user story mapping, ADRs, milestones, and backlog management
Designing and developing core APIs, setting up CI/CD pipelines, OpenTofu/Terraform scripts
Representing and communicating the team with third-party stakeholders (e.g. env zero)
(Cross-)team coaching on DevOps, software design, Terraform, Golang, and agile practices
Fady K.
Last position:
Senior Software Developer / Tech Lead at Specific Objects Technologies GmbH
- Project 1: Multi-Tenant SaaS Platform: Data Integration & Pricing Management
- Objective: New development of ELT pipeline (replacement for Java 6 legacy), integration of heterogeneous source systems (CSV, Excel, Email, external DBs), event-sourcing for complete auditability, multi-tenant architecture for tenant-capable data processing
- Challenge: Processing millions of records daily, audit compliance, data isolation between different tenants
- Solution: Stakeholder workshops for requirements analysis, event-driven architecture with Axon Framework and Apache Kafka, AWS services (EC2, S3, Lambda, SQS, API Gateway) for cloud integration, PostgreSQL with tenant-specific schemas for multi-tenant data isolation, REST API design with Spring Boot for external system integrations, comprehensive testing strategy (JUnit, Spring Test, Postman, PACT, ArchUnit)
- Results: ELT performance improved from 30+ min to 1-5 min; 2-3 hours daily saved through workflow automation; 10-20 hours/week saved through event-sourcing auditability; 100% audit compliance; secure multi-tenant data isolation for 10+ tenants
- Project 2: Multi-tenant CRM System Modernization
- Objective: Migration of CRM system (20+ years PHP/MySQL) to Java microservices, Domain-Driven Design implementation, establishment of Test-Driven Development, multi-tenant-capable SaaS architecture for multiple customer tenants
- Challenge: Remodeling complex business logic, no existing test culture, scalable tenant management with data isolation
- Solution: Comprehensive testing strategy (JUnit, Spring Test, Postman, PACT, ArchUnit), multi-tenant architecture with tenant-specific databases, REST API design with Spring Boot for cross-tenant integration, Kubernetes and Docker for container orchestration
- Results: 2Ă— performance improvement; deployment time reduced from 40+ min to 5-7 min; migration without production outages; scalable multi-tenant solution for 15+ customer tenants
- Technologies: Java, Spring Boot 3.x, Angular, Apache Kafka, AWS (EC2, S3, Lambda, SQS, API Gateway), PostgreSQL, Axon Framework, Kubernetes, Docker, GitLab CI, REST API
Khaled M.
Last position:
Senior/Staff Backend Engineer at Heycar (Mobility Trader GmbH)
- Heycar is a leading automotive platform redefining the used car market through intelligent data pipelines, multi-tenant services, and dealer-focused tooling. I led initiatives across backend architecture, data ingestion, and identity management to enhance scalability, reliability, and developer productivity.
- Ingestion Platform: Designed a unified ingestion platform with YAML-based configuration, enabling new dealer data pipelines to be onboarded without code changes, cutting setup time from ~2 months to 2-3 days and improving scalability by 40%.
- Keycloak Leadership: Acted as the company's Keycloak expert, scaling it for multi-tenant identity management and extending functionality with custom plugins and delegated admin APIs.
- Back-Office Tooling: Developed a back-office application integrated with Salesforce, enabling dealers to manage inventory, convert leads, and handle support requests in real time.
- Multi-Tenant Migration: Collaborated across backend teams to migrate Heycar's core services into a unified multi-tenant cluster, ensuring high availability.
- Frontend CI Optimization: Optimized monorepo delivery by implementing CircleCI dynamic config with NX, deploying only affected UI projects and drastically cutting build times.
- Observability & Mentorship: Enhanced monitoring and release reliability while mentoring backend engineers and improving code review standards.
Amit G.
Last position:
Authorized Officer - Software Engineer at UBS
- Built a fee proposal tool automating financial advisor fee calculations, reducing manual processing from hours to seconds.
- Developed Spring Boot microservices with REST APIs on Azure SQL, replacing mainframe procedures, improving latency by 60%.
- Migrated Tomcat applications from on-premises RHEL servers to Azure Kubernetes Service (AKS).
- Automated testing and deployment processes using CI/CD pipelines in GitLab, reducing deployment time by 90%.
- Streamlined recurring reporting workflows by automating report generation using Spring Batch.
Christian R.
Last position:
Freelance Data Engineer at Ingenieurbüro Christian Richter – Data, Cloud & Container
- Contributed to over 20 successful projects
Dirk U.
Last position:
Developer at Future Training & Consulting GmbH
Training course with exam for Spring Certified Professional.
- Environment: Spring Boot 3, Spring Framework 6, IntelliJ
Henning P.
Last position:
Backend Systems Development at Deutsche Bank/DWS/Morgenfund
- Developed backend systems for the DWS Investment App, a white-label investment solution (robo-advisor), and an investment solution for institutional clients.
- Java 8-17, Kotlin, Spring Boot, Spring MVC, OpenAPI 3.0, JPA, JDBI, Oracle, Hazelcast, JXLS, Apache POI, Apache PDFBox, Apache Kafka & Avro, Active MQ, Elasticsearch, React Native, Spock Test, IntelliJ IDEA, Kubernetes, Helm, Microservices/Netflix-Stack, TeamCity, Splunk.
- Kanban team, continuous integration.
- Migrated existing applications from Deutsche Bank's private cloud environment to Azure as part of a carve-out.
Mario E.
Last position:
Developer and Consultant at Freelancer
Discover over 15,000 top freelancers
Statistics of experts using Apache Cassandra
Aggregated from the professional profiles of matched freelancers.
Experience
19 years (Germany: 20 years)
Position duration
2.9 years (Germany: 2.3 years)
Positions per freelancer
12 (Germany: 14)
Top business areas
Information Technology, Product Development, Business Intelligence
Top industries
Information Technology, Education, Media and Entertainment
Certification focus areas
Information Technology, Product Development, Quality Assurance
Bachelor's degree or higher
89% (Germany: 94%)
Master's degree or higher
44% (Germany: 54%)
Certifications per freelancer
1 (Germany: 2)
Most common languages
German, English, French
Speak two or more languages
100% (Germany: 98%)
Based on our profile pool as of 29 Oct 2026.
Daily rate distribution
The chart shows how the daily rates of experts in this technology in Berlin are distributed, based on recent contracts on our platform. Each bar covers a rate range — its height shows the share of experts charging within that range.
Average rates of experts in Berlin using Apache Cassandra
Rates are based on recent contracts and do not include FRATCH margin.
The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.
The median daily rate is the middle value of all daily rates — half of comparable freelancers charge less, half charge more. Unlike the average, it is barely affected by outliers.
Calculated based on our freelancers’ daily rates as of 29 Oct 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
Apache Cassandra experts industry focus
See which industries our matched freelancers work in most often — every figure is calculated live from the freelancers on FRATCH.
- Information Technology (100%)
- Education (50%)
- Media and Entertainment (42%)
- Professional Services (42%)
- Banking and Finance (33%)
- Healthcare (33%)
- Retail (33%)
- Utilities (33%)
Please note that freelancers can work across multiple industries, so percentages overlap.
About the technology
Distributed data store
Apache Cassandra is an open-source, wide-column NoSQL database built for high availability, horizontal scaling and continuous operation. It distributes data across many nodes without relying on a central server. Teams use it for time-series data, event streams, user activity, messaging and other workloads that must keep accepting requests during infrastructure failures.
Data modelling
Cassandra data models start with the queries an application must answer. Experts define partition keys, clustering columns, replication strategies and consistency levels around those access patterns. They also plan table shapes, compaction, tombstones and repair processes so read and write performance remains predictable as data volume grows.
Ecosystem and tooling
The technology fits into a broad operational and application ecosystem:
- Configure clusters, keyspaces, replication and multi-region deployments
- Connect services through the Java, Python, Go or Node.js drivers
- Operate Cassandra with Kubernetes, cloud infrastructure and infrastructure-as-code
- Monitor latency, compaction, disk use and node health with suitable observability tools
Apache Cassandra also works with streaming and analytics systems such as Apache Kafka and Apache Spark. CQL gives teams a familiar way to define schemas and query data, while tools such as nodetool support diagnosis and maintenance.
When expertise matters
Companies bring in freelance specialists when a new workload needs distributed persistence, an existing cluster shows unstable latency, or a migration from a relational database has stalled. They also help with cloud moves, multi-region resilience, capacity planning and upgrades. In Berlin, this expertise can support local product, media, mobility and industrial teams while remaining practical for remote collaboration across Europe.
- Design a schema for new query patterns
- Investigate slow reads, failed repairs or uneven partitions
- Prepare migration, backup and disaster-recovery plans
- Review operational readiness before launch
Strong professionals
Strong Apache Cassandra professionals understand distributed systems rather than treating the database like a conventional SQL store. They can explain consistency trade-offs, detect hot partitions, manage repair and compaction, and test failure scenarios. They document decisions clearly and work comfortably with application teams, operations specialists and stakeholders in English or German when Berlin-based collaboration requires it.
Choosing the right fit
Assess specialists through real design discussions, incident examples and evidence of production ownership. Ask how they would model your main queries, handle a region outage and measure cluster health. The right person connects schema decisions to application behaviour, automation and business risk, instead of promising that Cassandra alone will solve every scaling problem.
Frequently asked questions
The facts hiring teams ask for most often when it comes to Apache Cassandra.
Apache Cassandra is used for applications that need high write availability, predictable access patterns and data distributed across several machines or regions. Common workloads include event histories, telemetry, messaging, product activity and time-series records.
Apache Cassandra is designed for distributed scale and resilient writes, while PostgreSQL offers rich relational queries, joins and transactional features. The better choice depends on access patterns, consistency needs and whether the data has strong relationships that must be queried flexibly.
Apache Cassandra can suit teams that want an open-source distributed database with deployment flexibility across cloud or on-premises environments. DynamoDB offers a managed AWS experience, while ScyllaDB targets compatible workloads with a different implementation and operational model.
A strong Apache Cassandra specialist should understand distributed systems, data modelling, Java or another application language, Linux, networking and observability. Experience with Kubernetes, cloud infrastructure, Apache Kafka and infrastructure automation is also useful for production work.
Apache Cassandra work benefits from production experience with partition design, replication, repairs, compaction and failure recovery. A small proof of concept may need focused database knowledge, but a multi-region service should involve someone who has operated clusters under real load and incidents.
Apache Cassandra projects are well suited to remote collaboration when requirements, schemas, runbooks and access procedures are documented. Berlin teams should agree on working hours, incident coverage and language expectations early, especially when production support crosses time zones.
Ask an Apache Cassandra freelancer to model a representative query set and explain the partition-key choices. Strong answers cover consistency, hot partitions, repair, compaction, backup, monitoring and what happens when nodes or regions fail.
Apache Cassandra is often misused when teams copy a relational schema, depend on joins or create partitions that grow without control. Other risks include ignoring tombstones, delaying repair, choosing consistency levels without a clear reason and measuring only average latency instead of tail behaviour.
The average hourly rate of freelancers in Berlin, Germany who have used Apache Cassandra in their recent projects is 96 €, which corresponds to a daily rate of about 765 € based on an 8-hour working day.
Of the freelancers in Berlin, Germany who have used Apache Cassandra in their recent projects, 89% hold at least a Bachelor's degree and 44% hold at least a Master's degree.
On average, freelancers in Berlin, Germany who have used Apache Cassandra in their recent projects have 19 years of professional experience, with a single engagement typically lasting around 2.9 years.
The most common languages among freelancers in Berlin, Germany who have used Apache Cassandra in their recent projects are German (100%), English (100%), and French (25%).
The most common industries among freelancers in Berlin, Germany who have used Apache Cassandra in their recent projects are Information Technology (100%), Education (50%), and Media and Entertainment (42%).
The most common business areas among freelancers in Berlin, Germany who have used Apache Cassandra in their recent projects are Information Technology (100%), Product Development (100%), and Business Intelligence (58%).
Main locations of FRATCH Experts, who have recently used Apache Cassandra
Our freelancers and interim experts are at home across the DACH region — available on-site in the major business hubs or fully remote. Choose a location to discover matched specialists, local market insights and up-to-date availability.
Berlin 
Hamburg Munich Cologne Frankfurt Stuttgart Dusseldorf Leipzig Dortmund Essen Bremen Dresden Hanover Nuremberg 
Munich Request a free demo
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