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REST API Experts in Frankfurt

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Hire experts who design resource-based interfaces, secure data exchange and connect web or mobile products with business systems. Get precise access to vetted, available freelancers who match your REST API requirements quickly.

Meet FRATCH Experts in Frankfurt, who have recently used REST API

Verified expert

Boian V.

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Solution Architect

Frankfurt
Boian V.

Last position:

Solution Architect at DB InfraGO AG

The Base Services of DB InfraGO form a central data hub between the company’s IT systems. Common Data Services are developed that distribute data from source systems to a variety of downstream systems (via JMS) and make them available (via REST API). The existing service landscape based on TIBCO is being migrated to DB InfraGO’s cloud-native platform.

  • Architecture design and implementation for performance-optimized bulk data processing of several million datasets at specific times during the day
  • Technical specification and documentation of business requirements
  • Integration of various subsystems (including SAP and Salesforce) through the reimplementation of more than 40 microservices based on Spring Boot
  • Migration of TIBCO Based microservices from the Enterprise Integration Platform to the Cloud Native Platform using Spring-Boot
  • Establishment of a deployment pipeline using GitLab CI/CD, Artifactory, and automated deployment to a Kubernetes environment with the help of ArgoCD
  • Definition and implementation of automated unit, integration, and regression tests

Team Size: 9

Technologies/Tools: Java, Spring Boot, ActiveMQ(JMS), JUnit, Tibco Business Works, Gitlab (CI/CD), Kubernetes (Amazon AWS), ArgoCD, postgreSQL, Oracle, Postman, Hoppscotch, openAPI, Sonarqube

Verified expert

Ali A.

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Enterprise Software Architect | Payments, Cloud & AI Platforms

Frankfurt
Ali A.

Last position:

Founder & Architect at Independent AI R&D

  • Fully on-premises LLM document-examination platform for a compliance-critical banking domain: agentic LangGraph pipeline with deterministic verification, every AI judgment structured and source-anchored; ~960 automated tests, zero data egress
  • GPU throughput engineering (quantized serving, speculative decoding, prefix caching): 9.5x extraction speed-up, 500+ multi-document case files per day on a single A100
  • AI-native EDI/EDIFACT integration platform (~116k LOC Java 25 / Spring Boot 4, 1,900+ tests): LLM-drafted partner mappings machine-verified before go-live (DFDL conformance, field-coverage checks, dry runs), ~99.5% byte match on real customer files — replacing weeks of manual mapping per partner
Verified expert

Waseem S.

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Enterprise Solution Architect |5G / Mobile Communications|Mission Critical Services (MCx)|IMS and SIP

Frankfurt am Main
Waseem S.

Last position:

Solution Architect / Subject Matter Expert at FRMCS terminal device manufacturer

Participation in the EU-funded MORANE-2 project to validate the Future Railway Mobile Communication System (FRMCS) in real-life use cases: creation of the requirement specifications for TOBA as well as the associated test specifications.

Technologies: 5GS (Radio & Core), FRMCS, MCx (MCPTT, MCData, MCVideo), MC Gateway UE, MCx Priority/Security/QoS Management, ETCS, SIP, IMS

Verified expert

Michael H.

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Senior Frontend Engineer · Frontend Tech Lead · Lead UI Engineer

Kelsterbach
Michael H.

Last position:

Frontend Developer at RTL Tech

  • Development and optimization of the RTL+ frontend application for SmartTV and set-top box platforms with React and Next.js.
  • Key role in the technical coordination of developers within the team and in coordinating implementation.
  • Central interface to adjacent teams to simplify development processes and improve cross-team alignment.
  • Improved frontend performance, stability, and rendering behavior on low-powered devices in a restricted runtime environment.
  • Implemented a frontend testing strategy with Jest, React Testing Library, and Playwright.
  • Implemented accessibility improvements according to WCAG 2.2 and WAI-ARIA.
  • Integrated Didomi Consent Management as a contribution to increasing ad monetization on streaming platforms.
  • Used AI-supported engineering workflows with Cursor for structured implementation, refactoring, and faster problem solving.

Technologies used: React, Next.js, TypeScript, JavaScript, GraphQL, Apollo Gateway, Zustand, Tailwind CSS, Styled Components, React Testing Library, Playwright, Jest, HTML5, CSS3, AWS Lambda, EC2, CloudFront, S3, GitLab CI/CD, NX, Cursor

Verified expert

Sören K.

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Senior Project Manager

Bad Vilbel
Sören K.

Last position:

Epic-Owner at Telefonica Deutschland

#Coordination of the introduction of the new CCT platform in the RAITT project in the Customer Service area for the inbound channels Call/Email/Letter and Web/App.

  • Design of the rights and roles concept in Phase 1 of the Salesforce product launch.
  • Coordination with Enterprise and Solution Architects regarding future system interfaces (APIs, REST APIs).
  • Close coordination with the affected business units and project teams across tribes. Support for the introduction of the new CCT platform in Sprinklr and its dependencies on RAITT for all inbound channels.
  • Preparation and coordination of works council-related topics with HR and Application Owners.
  • Creation and optimization of process flows for inbound feature-related business processes and their modeling. #Toolset: JIRA, Confluence, Camunda, Aris, Salesforce, SCRUM
Verified expert

Saqib J.

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Senior Solution & Software Architect · Interim IT Lead · AI/Agentic AI, Cloud, .NET

Erlensee
Saqib J.

Last position:

AI Developer / AI Engineer (Lead) at KOM4TEC GmbH

  • Conceptual design and implementation of modular AI assistants for sales and business processes in the Microsoft ecosystem (Agentic AI, Copilot extensions)
  • Frontend architecture and development with React + TypeScript for embedded chat and assistant surfaces (streaming UI, hooks, React Query, OpenAPI clients)
  • Enterprise-level agent development: reusable skill/agent library, MCP server, review and compliance gates
  • LLM integration into the user experience: Anthropic (Claude), OpenAI, tool use, RAG pipelines, prompt engineering, guardrails
  • Architecture and code review consulting as well as mentoring in the AI development team
  • Integration with Microsoft Graph, Power Platform, and Azure services
  • Technologies: React, TypeScript, Anthropic Claude, OpenAI, MCP, RAG, Microsoft Graph, Power Platform, Azure
Verified expert

Torsten F.

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Data Analyst, Requirements Manager

Dreieich
Torsten F.

Last position:

Data Analyst, Requirements Manager at Isabellenhütte Heusler GmbH

  • Analysis of the existing reporting platform including processes and governance topics with stakeholders from sales and marketing.

  • Detailed analysis and evaluation of client-defined requirements for existing reporting and new dashboards.

  • Supporting stakeholders in managing sales processes and early detection of KPI trends.

  • Use of Microsoft Power BI as central analysis and reporting platform.

  • Developing a proposal for the necessary evolution of processes and the Power BI platform.

  • Gathering current business processes and defining company-wide KPIs in coordination with stakeholders.

  • Analysis and inventory of the client's Power BI platform.

  • Analysis of processes and data governance.

  • Recording and documenting current business processes.

  • Developing recommendations for process and reporting platform improvements.

  • Designing and implementing dashboards in Power BI.

  • Defining company-wide KPIs and aligning them with stakeholders.

  • Microsoft Power BI.

  • Data analytics.

  • KPI definition and reporting.

  • Dashboard design and data visualization.

  • Stakeholder management and requirements management.

Verified expert

Anthony M.

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CodeValdCortex - Enterprise Multi-Agent AI Orchestration Platform

Frankfurt
Anthony M.

Last position:

Research and Development, AI for Enterprise at Mwanachama

  • Built an MCP (Model Context Protocol) layer for Mwanachama's agency service, turning domain manager methods into callable AI-agent tools. This included a composite tool that builds a full organization design (org chart, goals, workflows, RACI matrix) from one specification.
  • Built the chat-driven agency builder (Wakala Studio and API), where an organization describes its structure in natural language and an AI agent uses those tools to construct and modify the live design.
  • Added an insights service so an organization can review AI-agent interactions and completed work. Insights from that review feed back into solution design, gated by architect and user sign-off.
  • Alongside this, designed and built the platform itself: ~20 Go microservices on PostgreSQL, Flutter and React clients, deployed on Kubernetes.
  • AI agents scan the platform autonomously for security gaps and run scripted tests, covering API (Postman-style) and UI testing. The rest of the work stays supervised. No rogue agents, promise.
Verified expert

Matthias V.

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Freelance IT Project Manager

Hattersheim am Main
Matthias V.

Last position:

Freelance IT Consultant at Freelance IT Consultant

Verified expert

Noel L.

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Founder & Lead Engineer

Frankfurt
Noel L.

Last position:

Founder & Lead Engineer at ausbildung-in-der-it.de

  • Platform established and running stably; deliberately reducing my involvement to refocus on an engineering mandate in the financial sector.
  • Built an own SaaS learning platform from the ground up and scaled it to over 20,000 users (over 6,000 courses sold, B2C and B2B); end-to-end ownership from development through infrastructure to operations.
  • Built a lab environment that provisions an isolated Linux container per user (Docker, Traefik, Go), including automatic provisioning and a dedicated subdomain per user.
  • Integrated LLM features into the product and accelerated development end-to-end with AI-assisted workflows (Claude Code, Codex); CI/CD with automated tests.
Verified expert

Uday V.

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Full Stack Java Developer and DevOps Engineer

Frankfurt am Main
Uday V.

Last position:

Senior Full Stack Java Developer & DevOps Engineer at Deutsche Börse (DBAG)

Project: SCS (Settlement / Clearing Services)

Settlement platform serving multiple trading and clearing venues — counterparty risk safeguarding, settlement volume reduction, central risk management, and post-trade anonymity.

Technologies: Java 17, Spring Boot 3, Microservices, Spring Data JPA, SonarQube, Fortify (SCST), Mockito, Jenkins, OpenShift, Maven, Podman, GitHub, JIRA, Liquibase, Swagger, AMQP, Apache Camel, Terraform, PostgreSQL, Instana, Graylog.

  • Identified and remediated CVEs in third-party libraries using SCA tooling, strengthening the security posture of production components.
  • Maintained 90% code coverage with SonarQube, improving code quality and reducing production defects.
  • Enabled mTLS for database authentication and message broker connections, enforcing encrypted, certificate-validated communication.
  • Designed and deployed microservices with asynchronous, REST-based communication between components.
  • Optimized a high-volume REST API (~200K requests) by reducing response time from 3s to 2s (33% improvement), boosting throughput and reliability under production load.
  • Automated build and continuous integration pipelines using Maven and Jenkins.
  • Orchestrated containerized workloads on Podman/OpenShift and governed schema evolution with Liquibase, ensuring reliable, repeatable deployments across all environments.
  • Optimized Java code and implemented EHCache-based caching, improving application performance.
  • Streamlined release management by governing application images, JAR versions, and dependencies through DBAG Artifactory, ensuring version consistency and audit traceability across environments
Verified expert

Muhammad U.

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Software Engineer | React js | Node js | Next js | Express js | Next js | PHP | Laravel | MySql | Driven by Delivering

Frankfurt am Main
Muhammad U.

Last position:

Software Engineer at Absolutely Digital

Verified expert

Umut G.

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Freelancer

Frankfurt
Umut G.

Last position:

Data Architect at BA Technology

I am an experienced data engineer specializing in end‑to‑end data integration, cloud DWH architectures, and high‑quality, governed data products.

I delivered following projects and engagements as a freelancer.

  • Data Migration of CRM System for AL-FA Objekt Service Gmbh
  • Microsoft Software Resales Partnership

I am looking for freelance roles like: Freelance Data Engineer Cloud Data Warehouse Architect Data Modeling & Architecture Consultant MDM & Data Governance Specialist BI & Analytics Developer

Technical Focus Areas

  • Data Engineering & Integration: SQL Server/SSIS, Informatica PowerCenter/IDQ, Talend, Kafka, Azure Data Factory – Delta/CDC/ELT patterns, robust pipelines, monitoring/recovery, data lineage & impact analysis, medallion architecture Bronze/Silver/Gold layers
  • DWH & Cloud: Azure SQL / Data Lake / Synapse, AWS Redshift/S3, on‑prem SQL/Oracle – scalable data marts with a strong cost/benefit focus.
  • Data Modeling: Atomic (Inmon) and Dimensional (Kimball), Data Vault (Linstedt), Domain‑Driven Design, clear lineage & contracts.
  • MDM & Governance: Informatica MDM, IBM MDM, stewardship processes, data quality rules, survivorship/XREF, catalog/glossary, SIF/BES/REST publication.
  • Analytics/BI: Power BI, SSAS, Cognos – business‑ready, maintainable data products.
Verified expert

Mobin R.

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Senior Consultant and Chief Product Owner

Frankfurt am Main
Mobin R.

Last position:

Senior Consultant and Chief Product Owner at Luxota Travel Tech

  • Coached teams in Agile methodologies and Scrum framework implementation.
  • Aligned the product roadmap with business goals such as increasing bookings, improving user experience, and expanding supplier integrations.
  • Collaborated with developers and third-party providers to ensure smooth API integration and end-to-end functionality.
  • Created and continuously refined the product backlog with user stories, bugs, and technical improvements.
  • Prioritized backlog items based on business value, revenue impact, and regulatory deadlines.
  • Worked closely with backend and frontend teams to clarify dependencies and prioritize technical debt.

Discover over 15,000 top freelancers

Statistics of experts using REST API

Aggregated from the professional profiles of matched freelancers.

Experience

18 years (Germany: 17 years)

REST API experts in Frankfurt have 18 years of professional experience on average. It is 1 year more than in Germany, where the average stands at 17 years.

Position duration

2.3 years (Germany: 2.9 years)

REST API experts in Frankfurt stay in a single position for 2.3 years on average. It is 0.6 years less than in Germany, where the average stands at 2.9 years.

Positions per freelancer

13 (Germany: 12)

REST API experts in Frankfurt have completed 13 positions on average over the course of their careers. It is 1 more than in Germany, where the average stands at 12.

Top business areas

Information Technology, Product Development, Quality Assurance

REST API experts in Frankfurt have gathered most of their hands-on project experience in Information Technology, Product Development, and Quality Assurance.

Top industries

Information Technology, Banking and Finance, Transportation

REST API experts in Frankfurt are most in demand in Information Technology, Banking and Finance, and Transportation.

Certification focus areas

Information Technology, Project Management, Product Development

REST API experts in Frankfurt earn their certifications most often in Information Technology, Project Management, and Product Development.

Bachelor's degree or higher

97% (Germany: 92%)

97% of REST API experts in Frankfurt hold at least a Bachelor's degree. It is 5% higher than in Germany, where the rate stands at 92%.

Master's degree or higher

52% (Germany: 55%)

52% of REST API experts in Frankfurt hold at least a Master's degree. It is 3% lower than in Germany, where the rate stands at 55%.

Doctorate

8% (Germany: 7%)

8% of REST API experts in Frankfurt have a doctorate (PhD). It is 1% higher than in Germany, where the rate stands at 7%.

Certifications per freelancer

3

REST API experts in Frankfurt hold 3 professional certifications on average.

Most common languages

German, English, Russian

REST API experts in Frankfurt most often speak German, English, and Russian.

Speak two or more languages

97%

97% of REST API experts in Frankfurt speak two or more languages.

Based on our profile pool as of 19 Sep 2026.

Daily rate distribution

0 10 20 30 40
3 of the REST API experts in Frankfurt charge less than €400 per day.
34 of the REST API experts in Frankfurt charge between €400 and €800 per day.
33 of the REST API experts in Frankfurt charge between €800 and €1200 per day.
3 of the REST API experts in Frankfurt charge €1200 or more per day.
<€400 €400-​800 €800-​1200 €1200+

The chart shows how the daily rates of freelancers in this technology in Frankfurt 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 Frankfurt using REST API

Rates are based on recent contracts and do not include FRATCH margin.

800
600
400
200
Rate comparison chart
Daily rate avg. 754 €
Germany avg. 739 €

The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.

800
600
400
200
Rate comparison chart
Median rate 760 €
Germany median 760 €

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.

REST API 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 (95%)
  • Banking and Finance (63%)
  • Transportation (42%)
  • Healthcare (35%)
  • Telecommunication (35%)
  • Automotive (33%)
  • Education (33%)
  • Retail (31%)

Please note that freelancers can work across multiple industries, so percentages overlap.

About the technology

What REST API means

REST API is a way for software systems to exchange data through standard HTTP requests. It models business objects as resources and uses predictable endpoints, methods and status codes. Companies use it to connect web applications, mobile products, partner services and internal systems.

Where it is used

REST interfaces support customer portals, ecommerce services, payment flows, logistics tools and data platforms. They expose focused capabilities while keeping frontend and backend systems separate.

  • Connect web and mobile applications to backend services
  • Publish partner and customer-facing integrations
  • Move data between business systems and cloud services
  • Support resource creation, updates, searches and deletion

Ecosystem and tooling

Strong REST API specialists work across HTTP, JSON, authentication and relational or document databases. They may use OpenAPI or Swagger for contracts and documentation, Postman for request testing, and tools such as Java with Spring Boot, .NET, Node.js or Python frameworks. Version control, automated tests and observability complete the delivery process.

When companies need specialists

Freelance expertise helps when an existing interface is unreliable, undocumented or difficult to extend. It is also valuable during a system replacement, a partner integration, a security review or a move from tightly coupled applications to well-defined services.

  • Define endpoint structure and resource models
  • Establish authentication, authorization and validation
  • Improve response times, error handling and reliability
  • Create OpenAPI documentation and integration tests

What quality looks like

Experienced professionals design interfaces that are consistent, secure and understandable for the teams consuming them. They choose suitable status codes, protect sensitive data, handle backward compatibility and document edge cases. They also consider pagination, filtering, idempotency and rate controls rather than treating an endpoint as an isolated task.

Working with Frankfurt teams

Companies in Frankfurt can involve REST API specialists in financial services, logistics, commerce and enterprise software work. Remote collaboration is often effective when requirements, API contracts and review routines are explicit; on-site sessions can help with complex stakeholder alignment. German or English communication should match the project team and its documentation needs.

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Frequently asked questions

The facts hiring teams ask for most often when it comes to REST API.

A REST API lets separate software systems exchange resources and actions through HTTP. Companies use it to connect interfaces with backend services, expose partner integrations and link applications to business platforms.

REST API uses resource-oriented endpoints and standard HTTP behavior, which makes it widely understood and easy to integrate. GraphQL gives clients more control over returned data, while SOAP offers a stricter contract and enterprise messaging model; the right choice depends on compatibility, governance and data needs.

A capable REST API specialist should understand HTTP, JSON, authentication, databases and automated testing. Useful adjacent skills include OpenAPI, cloud deployment, CI/CD, observability, secure coding and at least one backend ecosystem such as Spring Boot, .NET, Node.js or Python.

The required depth depends on risk and scope. A simple internal interface may need focused implementation skills, while public integrations require strong judgment around security, versioning, resilience, documentation and backward compatibility. Ask for examples close to the systems your company operates.

Yes. REST API work is often well suited to remote collaboration because contracts, test collections, code reviews and documentation can be shared online. Frankfurt teams should agree on meeting routines, ownership of interface decisions and whether German, English or both are needed.

Bring in a REST API freelancer when an integration is blocking delivery, an interface needs to be redesigned or internal teams lack capacity for secure service work. Specialists can also assess an existing API, create missing documentation or prepare a migration plan.

Review whether the REST API specialist explains resource design, errors, security and compatibility in concrete terms. Look for clear documentation, meaningful automated tests and examples of handling failure cases, not only successful requests. A short technical review can reveal how they reason about trade-offs.

Usually not by itself. REST API knowledge must be combined with an understanding of the connected business systems, data mapping, authentication rules and deployment environment. For a successful delivery, clarify whether the specialist also owns backend changes, frontend integration, infrastructure or stakeholder coordination.

The average hourly rate of freelancers in Frankfurt, Germany who have used REST API in their recent projects is 94 €, which corresponds to a daily rate of about 754 € based on an 8-hour working day.

Of the freelancers in Frankfurt, Germany who have used REST API in their recent projects, 97% hold at least a Bachelor's degree, 52% hold at least a Master's degree, and 8% hold a doctorate.

On average, freelancers in Frankfurt, Germany who have used REST API in their recent projects have 18 years of professional experience, with a single engagement typically lasting around 2.3 years.

The most common languages among freelancers in Frankfurt, Germany who have used REST API in their recent projects are German (100%), English (96%), and Russian (17%).

The most common industries among freelancers in Frankfurt, Germany who have used REST API in their recent projects are Information Technology (95%), Banking and Finance (63%), and Transportation (42%).

The most common business areas among freelancers in Frankfurt, Germany who have used REST API in their recent projects are Information Technology (100%), Product Development (88%), and Quality Assurance (64%).

Main locations of FRATCH Experts, who have recently used REST API

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.

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