
REST API Experts in Germany
, matched in minutes by AIHire experts who design resource-based interfaces, secure API integrations and scalable backend services with tools such as OpenAPI, OAuth and Postman. FRATCH connects you quickly with vetted, available freelancers whose skills match your project precisely.
Meet FRATCH Experts in Germany, who have recently used REST API
Silvia B.
Last position:
Business Consultant - Product Management Banking at Aareal Bank AG
- Focus on optimizing and further developing the internal customer EBICS application
- Functional and technical consulting for Aareal First Financial Solutions AG on EBICS standard products and applications in the areas of operations and further development, as well as project-related communication with external development partners and the product manufacturer to implement the corresponding technical optimizations
- As the functional coordinator, providing advice on content-related and regulatory requirements as well as technical prerequisites and requirements, and bringing these together at the functional level
- Consulting on the use of EBICS formats
- Reviewing the current EBICS standard for optimization and further development potential
- Analyzing the current state to identify development potential and deriving appropriate recommendations for action while considering regulatory requirements
- Conducting EBICS tests throughout the project
- Functional responsibility for requirements management and, in this context, recording and documenting requirements for such tests
- Designing a functional and sustainable test management system
- Conducting and evaluating tests
- Consulting on sustainable quality assurance and audits
- Project language: German and English
- Tools/Methods: MS Project, MS Office, MS Visio, TestRail, Confluence, Jira, Business Logics Bankkrecher, Business Logics Test Data Generator, Business Logics Banking Tool, Business Logics Test System, DBEAVER, Squirrel, Unix Virtual Machines, WinSCP, Kitty, Putty, various Aareal Bank products, Online Banking Portal, Aareal Sign, core banking system, SAP Blue Eagle, SAP RE-FX, Aareon Wodis Sigma, Haufe Real Estate Wowinex, GAP Group Immotion, UTS Karthago, SAP IS-U/Waste, SIV kVASy, various EBICS clients
Kathrin S.
Last position:
Requirements Engineer at Governikus GmbH & Co. KG
- Impact: Structured requirements analysis and quality assurance as a foundation for the further development of a software solution.
- Analysis, documentation, and coordination of requirements. Conducting stakeholder analyses, interviews, and workshops to gather and validate requirements. Conducting requirements reviews and working closely with business departments and development teams.
Techniques & Tools: Requirements Engineering, Stakeholder Management, Workshop Facilitation, System Context Modeling, Requirements Reviews, Quality Scenarios, Miro, Jira, Confluence
Florian S.
Last position:
AI Product Manager / Product Owner at AI Product
- Generative AI products for corporate clients, owned from strategy through specification to production.
- Central strategy, local configuration: multi-tenant AI assistant for occupational pension schemes (bAV), delivered as an interactive avatar with text and voice path. Three tenants run on one codebase, each with its own conversation guide, while the knowledge base, guardrails and escalation paths stay central
- Versioned, AI-ready knowledge base composed into a tenant-agnostic voice context and tenant-specific text prompts — the configuration layer that keeps local adaptation from forking the product
- Conversational design: answer limits, scope and off-topic handling, anti-hallucination rules, escalation and lead handover to human advisors
- Five eval suites as a quality gate before any prompt or model change (anti-hallucination, LLM-as-judge failure modes, multi-turn consistency, voice KPIs, action vocabulary with confusion matrix); user test with 10 testers (Hamburg, 07/2026) drove the rework from alpha to beta
- Coordinated external developers, compliance and client stakeholders; GDPR-compliant EU stack, IDD-compliant, EU AI Act classification documented
- Second product line: white-label social media generator for consultancy chilli mind (CH/DE) — one codebase, per-client branding and configuration
- Results: 239+ deployments and a pilot with corporate customers · 108+ deployments for the white-label product · repeatable pattern for multi-tenant AI products in a regulated environment
Gabin Maxime N.
Last position:
Multi-Agent R&D Pipeline (3 Custom Agents) at Independent Project
Claude Code subagents, MCP, Pydantic V2, pytest, bandit
Designed and shipped 3 specialized agents that hand work down a line: a research agent writes a cited implementation spec, a coding agent builds the modular code and its tests, a review agent ranks findings by severity and applies the fixes. Each handoff is a structured document, so no stage depends on another agent's context window.
Connected the research agent to an academic-research MCP server (Semantic Scholar, ArXiv, Hugging Face Hub, citation snowballing) so every reference traces to a tool result rather than the model. Gated commits behind ruff, mypy, pytest and bandit, required human sign-off before installs and commits, and persisted session state on disk so long runs survive a context reset.
Onur K.
Last position:
Project Manager & Outsourcing Manager at SENEC GmbH (EnBW Group)
- Built a scalable nearshore IT developer hub (Croatia, Czech Republic, Poland) as an independent company through a BOT model (Build – Operate – Transfer)
- Identified, selected, and managed full-service agencies; introduced management and control mechanisms, including KPIs, SLAs, and regular service reviews
- Prepared and reviewed data processing agreements and framework contracts in coordination with Legal & Compliance; integrated regulatory requirements (including KRITIS) into process design
- Advised on cloud vs. on-premise strategies, data storage, and authorization concepts; supported Procurement with tendering and service provider evaluations
- Managed change and process harmonization between internal teams and nearshore partners; reported to executive management, CFO, and CIO
Result: Scalable IT developer hub with an audit-ready governance model, reduced operating costs, and accelerated product development.
Ornel Franck W.
Last position:
Sales Partner at ERGO PRO
- Industry: Insurance, Trade, IT
- Customers & Projects: Consulting and selling insurance and similar services
- Main tasks: Insurance consulting (health insurance, retirement planning, wealth building); commercial services, inside and field sales; sales data analysis and forecasting; customer consulting and support; opening a new sales headquarters for private and business customers; business development & innovation management; business use case development; process optimization; stakeholder management; team leadership and training; preparation and delivery of trainings;
- Technologies used: Microsoft Office 365, Microsoft Teams, Jira, Draw.IO, Camunda 8, Java (8, 17,21,25), Git, Spring Boot, Spring Batch, Spring Data REST, Spring Web, Spring Security, J-Unit, Playwright, Lombock, Vaadin, H2, PostgreSQL (16, 17 18), pgAdmin, Docker, LLMs, JasperSoft Studio, JasperReports
Thomas P.
Last position:
Product Owner & AI Automation Architect (B2B) at Ihre-Hygieneberatung
Development of a digital audit application for inspections in medical facilities. The goal is to connect on-site data collection, voice recording, documentation and downstream processes in one end-to-end, AI-supported workflow.
Design and development of a Flutter audit app with Claude Code for the structured execution and documentation of inspections.
Processing of voice recordings captured in the app through automatic transcription and AI-supported creation of structured inspection reports, followed by an approval process
Connecting various data sources such as email, Odoo 19, attendance records and Google Drive via n8n to automate billing and follow-up processes
Automatic provision of required documents and email delivery through n8n-controlled workflows, including the use of LLMs for text creation
Skills: Flutter, Claude Code, LLM Integration, n8n, Odoo 19, Google Drive, Process Automation
Ebru A.
Last position:
Product Analytics & App Tracking Consultant at EnBW mobility+ AG & Co. KG
- Product Analytics, Mobile App Tracking & Tracking Governance (B2C Mobility App) – agile project management (Scrum/Kanban)
- Product Ownership for Product Analytics and Mobile App Tracking of the EnBW mobility+ app; gathering, prioritizing, and translating business requirements into actionable concepts and Azure DevOps user stories with acceptance criteria.
- Derivation of tracking requirements when introducing new app features (including Resilient Map), definition of tracking parameters (screens, events, custom definitions), and ensuring privacy-compliant tracking (Firebase, GA4, Adjust) based on the tracking concept.
- Design and adaptation of dashboards and funnel reporting for campaigns (GA4 validation, onboarding and order flow analyses, conversion funnels, charging start flow) to identify drop-off points and optimization potential.
- Management of the technical raw data export (Adjust to BigQuery) and connection to the data warehouse/data lakehouse, including data mapping; collaboration with international development teams, Data Engineering, Marketing/Sales, and Product Management.
- Establishment of standardized tracking architecture, naming conventions, and governance; analysis and expansion of tracking (new features and “blind spots”), test design, handover to testers, and quality assurance and approval before releases; documentation in Conceptboard.
Wolfgang O.
Last position:
Project Manager at EnBW - Netze Südwest
- New development and further development of the existing MS Dynamics CRM
IT systems: Microsoft Dynamics Customer Service, SharePoint, DevOps, SAP IS-U
- CRM implementation / further development
- Taking over from the previous service provider
- Business process analysis
- Agile project organization
- Business analysis / requirements engineering with AI support
- Use of AI in development
- Analysis of master data processes
- CRM customer data management
- Requirements documentation
- Stakeholder management
- Workshop moderation
Peter S.
Last position:
Senior ML Engineer & AI Researcher at Anonymous Client
Project: Defect Generation on Test-Bench Images of Metal Surfaces Environment: Automated Visual Inspection (AVI), Metallurgy & Manufacturing
- Objective & Implementation: Designed, architected, and trained Generative Adversarial Networks (Pix2PixHD / SPADE) for image-to-image transformation. Targeted generation of synthetic material defects (e.g., cracks, inclusions, scale) on rough metal surfaces under real test-bench lighting conditions for privacy-compliant and efficient dataset expansion (data augmentation).
- Technical Design: Implemented robust Generative AI and computer vision pipelines in Python and PyTorch. Used semantic segmentation approaches for mask-controlled defect synthesis and subsequent evaluation with EfficientDet object detection models.
- Business Impact: Massive dataset upscaling (10x) without time-consuming and costly physical test-bench runs, while significantly improving the detection performance of automated inspection systems.
Technologies & Skills Used: Python | PyTorch | SPADE | Pix2PixHD | EfficientDet | Machine Learning | Semantic Segmentation | Computer Vision
Khalid E.
Last position:
Lead Architect & Developer at kem-consulting
Development of an agent-based governance platform for the automated assurance of EU AI Act compliance and ODA-compliant orchestration of AI services in complex enterprise environments.
Design and implementation of an agent-based "Mission Control" framework (Aletheia Conductor) for autonomous state monitoring and process control.
Development of "Compliance-as-Code" (CaC) solutions based on OPA/Rego for system-wide enforcement of regulatory guardrails.
Integration of TM Forum ODA standards (TMF630, TMF622, TMF642) to ensure interoperability and standardization.
Building a highly available event-driven architecture using Redpanda and CloudEvents v1.0 for near-real-time event processing.
Implementation of an audit-proof "Evidence Chain" through cryptographic linking of trace logs in preparation for automated audits.
Tech Stack: Java 21 (Quarkus Native), TypeScript (Next.js), Redpanda (Kafka API), CloudEvents v1.0, OPA (Open Policy Agent) & Rego, TimescaleDB, ZincSearch, Redis, TM Forum ODA, Git, GitHub, Clean Code Development, Like-C4.
Stefan O.
Last position:
Founder at ProtocolEngine.io
Evidence-led health intelligence platform turning published research into personal health protocols. It scores 430 habits, foods, and supplements against the studies behind them, and moves the score when the evidence moves. Built solo.
- Built the daily ingestion pipeline across PubMed, bioRxiv, and medRxiv: 43,000+ papers from 3,400+ journals processed into 230,000+ typed evidence claims, each one traceable back to the study it came from.
- Designed the six-factor evidence scoring model and the public changelog behind it, so no recommendation ever appears without the papers underneath it. 23,000+ grade changes recorded and explained to date.
- Shipped an entity information model connecting every intervention to its mechanisms, biomarkers, and outcomes: 118 biomarkers with region-specific reference ranges, 77 mechanisms, 32 graded outcomes.
- Built the personalisation layer: blood panel ingestion that reads lab PDFs with a vision model and corrects results for draw time against the user's wake anchor, plus Oura, WHOOP, and Withings integration for daily readiness context.
- Operate eleven specialised review agents over the corpus and codebase, covering paper curation, retrieval quality, health-claim compliance across EU and US regimes, and security.
- Shipped the Evidence Assistant, a RAG assistant that answers from the claim database and cites the underlying papers, plus a B2B practitioner tier, an Expo React Native app, and localisation across 3 languages and 7 markets.
Stack: Next.js 16, TypeScript, Supabase, pgvector, Anthropic Claude, Vercel, DeepInfra.
Kiriakos K.
Last position:
Tech Lead / Architect : OTTO API Platform at OTTO
Maturing their API practices on both a business and technology level. My role covers strategy, architecture, developer advocacy as well as hands-on software engineering, enabling both technical teams and business leadership to adopt and act on API-centric principles effectively. Coincidentally, we also establish GitOps, DX and platform best practices with this project.
Highlights:
- Aligning executives with the initiative by clarifying strategy, replacing misconceptions and myths with facts, clarifying the value of existing assets and enabling informed decision-making
- Formulating a way forward for API Lifecycle Management at OTTO
- Driving platform progress and fostering developer engagement by hands-on engineering work towards strategic goals
API Lifecycle Management, Team Topologies, Organizational Evolution, Regulatory, Platform Advocate, Developer Platform, Communities of Practice, Terraform, Kotlin, Kafka, Kong, WSO2, Apigee, Gravitee, Backstage, AsyncAPI, OpenAPI, API Design, AWS, React, Node.js, TypeScript, Redocly, reactive programming, CDC, Golang, Gin, GitOps, DX (developer experience), stakeholder management, roadmaps, workshops, discovery.
Sascha B.
Last position:
Web Developer at GxPlex
- Built a customized MediaWiki instance, including installation, MySQL database, SSL, and automatic backups
- Set up user roles (Admin, Mod, Verified, User) and a permissions system
- FlaggedRevisions for editorial review workflows · Commenting and rating extensions
Johannes H.
Last position:
Business Analyst for Riester subsidy management migration at Insurance company
- Analysis of the Riester subsidy GeVos for provider change 2.0 in the AZUR subsidy management system
- Representation of the GeVos in BPMN 2.0 with Draw.io and Adonis
- Analysis of the data sets exchanged with the life insurance policy administration system and migration to the msg data sets
- Design and mapping of the interfaces to the new msg.ZulagenVerwaltung for various Riester subsidy GeVos at data field level
Discover over 15,000 top freelancers
Statistics of experts using REST API
Aggregated from the professional profiles of matched freelancers.
Experience
17 years

Position duration
2.9 years

Positions per freelancer
12

Top business areas
Information Technology, Product Development, Quality Assurance

Top industries
Information Technology, Banking and Finance, Automotive

Certification focus areas
Information Technology, Product Development, Project Management
Bachelor's degree or higher
92%
Master's degree or higher
55%
Doctorate
7%

Certifications per freelancer
3

Most common languages
German, English, French

Speak two or more languages
97%
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 Germany 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.
Discover detailed REST API rate benchmarks:
Explore rate insightsAverage rates of experts in Germany using REST API
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.
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 (44%)
- Automotive (38%)
- Manufacturing (36%)
- Retail (36%)
- Professional Services (32%)
- Healthcare (31%)
- Education (28%)
Please note that freelancers can work across multiple industries, so percentages overlap.
About the technology
What REST APIs do
A REST API is a web interface that lets applications exchange resources over HTTP. Clients request or modify data through predictable endpoints, while responses commonly use JSON. REST APIs connect web applications, mobile products, partner services and internal systems without tying them to one user interface.
Core design principles
Good REST API work starts with clear resources, consistent URLs and the correct use of HTTP methods such as GET, POST, PUT and DELETE. Experts define status codes, validation rules, error formats and pagination so integrations remain understandable. Stateless requests and deliberate versioning help services scale and evolve safely.
Ecosystem and tooling
REST API specialists work across the full delivery chain, from contract design to monitoring in production. Common tools and related skills include:
- OpenAPI and Swagger specifications for shared API contracts
- OAuth 2.0, OpenID Connect and API keys for access control
- Postman, automated tests and contract testing
- Docker, Kubernetes and cloud gateways for deployment
- SQL, NoSQL and message queues behind the interface
Where companies use it
Companies use REST APIs to connect customer portals, mobile applications, payment services, logistics systems and data platforms. In Germany, specialists often support industrial, retail, finance and public-sector systems that must connect existing software with newer digital services. They can also replace fragile point-to-point integrations with documented interfaces.
When freelance expertise helps
Bring in a REST API expert when a product needs a new integration layer, an existing interface is difficult to change, or teams need reliable documentation and tests. Typical assignments include:
- Designing an API contract before implementation
- Integrating external services and partner systems
- Improving authentication, performance and error handling
- Preparing an API for a mobile or web product
- Reviewing security, versioning and operational risks
What strong professionals deliver
Strong REST API professionals think beyond endpoint creation. They align the interface with business processes, choose clear resource models and document decisions for every consuming team. They also measure latency, protect sensitive data, handle retries and backward compatibility, and explain trade-offs clearly in remote or on-site collaboration.
Frequently asked questions
Need clarity? These are the questions we hear most often about REST API.
A REST API lets separate applications exchange data and trigger actions through HTTP requests. Companies use it for web and mobile products, partner integrations, internal services, payments, reporting and access to business data.
A REST API usually exposes resources through multiple predictable endpoints and works well with standard HTTP caching and tooling. GraphQL gives clients more control over the response shape, while SOAP offers stricter message contracts and enterprise standards; the right choice depends on integration constraints, governance and data needs.
A REST API specialist should understand HTTP, JSON, authentication and data modeling, plus the service layer behind the interface. Useful adjacent skills include OpenAPI, OAuth 2.0, automated testing, SQL or NoSQL, observability, cloud deployment and API gateway configuration.
The scope of a REST API assignment matters more than a fixed experience threshold. A simple internal integration may need focused interface and testing skills, while a public API requires experience with versioning, security, traffic management, documentation and production support.
Most REST API tasks can be handled remotely because specifications, repositories, tests and monitoring are digital. On-site workshops may still help when specialists must map complex processes with several German-speaking teams or coordinate closely with existing infrastructure groups.
Review whether the REST API has consistent resource names, correct status codes, useful error responses and complete documentation. Ask for examples of automated tests, authentication design, backward compatibility and monitoring, then check whether the professional can explain trade-offs in clear terms.
A REST API may be a weak fit when clients need highly flexible queries, constant bidirectional updates or strict contract-based messaging across legacy systems. GraphQL, WebSockets, event-driven messaging or SOAP may suit those conditions better, sometimes alongside REST rather than instead of it.
Before accepting REST API work, clarify the consumers, resources, authentication model, data ownership and expected traffic. Also confirm documentation standards, deployment ownership, test environments, versioning policy and whether collaboration requires German-language workshops or can remain fully remote.
The average hourly rate of freelancers in Germany who have used REST API in their recent projects is 92 €, which corresponds to a daily rate of about 739 € based on an 8-hour working day.
Of the freelancers in Germany who have used REST API in their recent projects, 92% hold at least a Bachelor's degree, 55% hold at least a Master's degree, and 7% hold a doctorate.
On average, freelancers in Germany who have used REST API in their recent projects have 17 years of professional experience, with a single engagement typically lasting around 2.9 years.
The most common languages among freelancers in Germany who have used REST API in their recent projects are German (97%), English (96%), and French (15%).
The most common industries among freelancers in Germany who have used REST API in their recent projects are Information Technology (95%), Banking and Finance (44%), and Automotive (38%).
The most common business areas among freelancers in Germany who have used REST API in their recent projects are Information Technology (99%), Product Development (92%), and Quality Assurance (56%).
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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