Apache Cassandra Experts in Berlin
matched in minutes from over 15,000 CVsHire experts who design distributed data models, tune high-volume clusters and connect Cassandra with Kafka, Spark or Kubernetes. FRATCH matches you quickly and precisely with vetted, available freelancers for remote or on-site work in Berlin.
Meet FRATCH Experts in Berlin, who have recently used Apache Cassandra
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
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.
Ola V.
Last position:
IT Lecturer
- IT training in theory and practice for IT specialists in application development and system integration
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: 2× 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
18 years
Position duration
3 years
Positions per freelancer
12
Top business areas
Information Technology, Product Development, Business Intelligence
Top industries
Information Technology, Education, Professional Services
Certification focus areas
Information Technology, Product Development, Quality Assurance
Bachelor's degree or higher
88%
Master's degree or higher
38%
Certifications per freelancer
2
Most common languages
German, English, French
Speak two or more languages
100%
Based on our profile pool as of 19 Sep 2026.
Daily rate distribution
The chart shows how the daily rates of freelancers in this technology in Berlin are distributed, based on recent contracts on our platform. Each bar covers a rate range — its height shows how many freelancers charge 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 19 Sep 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 (45%)
- Professional Services (45%)
- Banking and Finance (36%)
- Media and Entertainment (36%)
- Utilities (36%)
- Automotive (27%)
- Healthcare (27%)
Please note that freelancers can work across multiple industries, so percentages overlap.
About the technology
Distributed data at scale
Apache Cassandra is an open-source wide-column NoSQL database built for workloads that need high availability, horizontal scaling and predictable performance. It spreads data across nodes without relying on a single point of failure. Companies use it for event data, customer activity, time-series records, messaging, product catalogs and other systems that must keep serving during infrastructure or network problems.
Data modeling
Cassandra requires a query-first approach rather than the relational pattern of normalizing data and joining tables at request time. Strong specialists design partition keys, clustering columns, replication settings and denormalized tables around known access paths. They also account for data growth, hot partitions, consistency requirements, tombstones and the cost of compaction.
Ecosystem and tooling
The technology fits into a broad distributed-data stack. Professionals commonly work with:
- CQL, the Cassandra Query Language, and native drivers for Java, Python, Go or Node.js
- Apache Kafka for event streams and change-driven ingestion
- Spark, Flink or analytical stores for larger processing workloads
- Kubernetes operators, cloud services and infrastructure automation
- Prometheus, Grafana and native tools for health and performance monitoring
When expertise matters
Companies bring in freelance expertise when a cluster is slow, unstable or difficult to operate safely. They may need a new data model, a migration from a relational database, multi-region replication or a review of consistency and recovery plans. Berlin teams can combine local workshops with remote delivery when architecture decisions involve several product and infrastructure groups.
Typical deliverables
A specialist can turn requirements into a tested Cassandra design and an operating plan. Common deliverables include:
- Partition and table models mapped to application queries
- Cluster deployment, scaling and rolling upgrade procedures
- Backup, restore, repair and disaster-recovery runbooks
- Load tests, query tuning and observability dashboards
- Migration pipelines with validation and rollback steps
What strong experts bring
Good Cassandra professionals understand distributed systems, not only CQL syntax. They can explain trade-offs between consistency, latency, availability and storage, then prove decisions with realistic workload tests. Look for experience with failure scenarios, repair operations, capacity planning, security controls and application-level retries. Clear documentation and collaboration in English, German or both can help Berlin-based teams keep ownership after the engagement.
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 continuous availability, high write throughput and data distributed across several locations. Common examples include telemetry, user activity feeds, messaging, recommendation inputs and time-series workloads.
Apache Cassandra favors denormalized, query-specific tables and distributed availability, while a relational database typically emphasizes joins, transactions and normalization. Cassandra is a strong fit when access patterns are known and the system must scale across nodes, but it is not a general replacement for relational reporting or complex transactional workflows.
A strong Apache Cassandra expert usually understands distributed systems, Linux, networking, cloud infrastructure and observability. Useful adjacent skills include Kafka, Kubernetes, Spark, infrastructure as code, application drivers and data migration design.
The right level depends on the risk and scope of the work. A simple application integration may need focused database expertise, while multi-region operations, migrations or recovery design require someone who has handled repair, failure testing, capacity planning and production incidents with Apache Cassandra.
Yes. Apache Cassandra work can be delivered remotely when access, documentation and operational ownership are clear. Berlin teams may still prefer on-site workshops for data-model reviews, incident simulations or coordination across product and infrastructure groups.
Ask the specialist to explain partition-key choices, consistency levels, replication, compaction and repair in terms of your actual queries and failure scenarios. A capable Apache Cassandra professional will show how they validate assumptions with load tests and monitoring instead of relying on generic tuning advice.
Apache Cassandra may be unsuitable when the workload depends on frequent ad hoc joins, strict multi-record transactions or flexible analytical queries. It can also add unnecessary operational complexity when the data volume, availability needs and access patterns are modest.
Freelancers should clarify the existing topology, cloud or data-center setup, replication strategy, consistency expectations, workload shape and on-call responsibilities. For Apache Cassandra, understanding the application queries and operational history is essential before changing schemas, compaction settings or cluster capacity.
The average hourly rate of freelancers in Berlin, Germany who have used Apache Cassandra in their recent projects is 93 €, which corresponds to a daily rate of about 747 € based on an 8-hour working day.
Of the freelancers in Berlin, Germany who have used Apache Cassandra in their recent projects, 88% hold at least a Bachelor's degree and 38% hold at least a Master's degree.
On average, freelancers in Berlin, Germany who have used Apache Cassandra in their recent projects have 18 years of professional experience, with a single engagement typically lasting around 3 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 (27%).
The most common industries among freelancers in Berlin, Germany who have used Apache Cassandra in their recent projects are Information Technology (100%), Education (45%), and Professional Services (45%).
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 (64%).
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.
Countries:
Berlin 
Hamburg Munich Cologne Frankfurt Stuttgart Dusseldorf Leipzig Dortmund Essen Bremen Dresden Hanover Nuremberg Request a free demo
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