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Daniel F.-Senior Backend Engineer

Daniel F.
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Available
Tulcea, Romania

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Experience

Sep 2024 - Jul 2026
United States

Senior Backend Engineer

Datasite

Position summary
Senior Backend Engineer at Datasite
Industries
Banking and Finance
Information Technology
Business areas
Information Technology
Product Development
Quality Assurance

A SaaS platform used by investment banks and private equity firms to run M&A transactions from diligence through close. The work covered the backend services on the company records underneath those deals: entity resolution against a large company database, record linkage from filings, model evaluation, and the validation and audit tooling that keeps automated decisions accurate and auditable.

  • Owned the backend services behind entity resolution in the deal workflow, where a wrong match reaches bankers mid transaction. Took match recommendations into production write paths with full audit trails.
  • Reviewed the product owner's initial spec, documented conflicts, recorded decisions in writing, then built and shipped the services.
  • Labelled a sample dataset before a large migration. Found that only 60% was usable and 10% contained reversed labels. Fixed the data issues before service design.
  • Added an LLM judge (Claude / Gemini) for cases the rules engine could not resolve. Measured 92.5% precision, found remaining errors from shared parent domains, and blocked auto approval until that pattern was fixed.
  • Fixed bad data handling and added checks so the same errors cannot reappear. Each fix is recorded in the same transaction, with validation at the API and again at save.
  • Mentored engineers to check that code matches the product and modelling rules, not only that it runs correctly.

Technologies: Python, FastAPI, C#, .NET, TypeScript, Dagster, PostgreSQL, Google Cloud (Cloud Run, Cloud SQL, Cloud Storage), Anthropic Claude API, Google Gemini API

Jun 2023 - Aug 2024
Germany

Senior Platform Engineer

Cognigy

Position summary
Senior Platform Engineer at Cognigy
Industries
Automotive
Information Technology
Tourism
Business areas
Information Technology
Product Development

An enterprise AI SaaS company with client-facing products across travel, automotive, and analytics. The work covered high-volume ingestion services and service infrastructure, cost-aware compute, and the CI/CD and evaluation standards used across the team.

  • Built the real-time and batch ingestion services behind a travel price comparison product, where a stale price costs a customer a booking. Terabyte-scale Kafka consumers sized against partition throughput and backpressure rather than average load.
  • Built the service layer that versioned training datasets for an automotive AI product, so every model result could be traced back to the exact data that produced it.

Technologies: Python, aiothp, Apache Kafka, Apache Airflow, Elasticsearch, AWS S3, Docker, GitHub Actions

Sep 2018 - Jun 2023
Germany

Platform Engineer

Cognigy

Position summary
Platform Engineer at Cognigy
Industries
Information Technology
Business areas
Information Technology

An enterprise AI SaaS company with client-facing products across travel, automotive, and analytics. The work covered high-volume ingestion services and service infrastructure, cost-aware compute, and the CI/CD and evaluation standards used across the team.

  • Ran the batch scoring and feature services behind client-facing dashboards, the numbers account managers quoted to clients. Workers for normalisation, currency conversion, and deduplication, scheduled on Airflow.
  • Treated compute cost as a margin question, not just latency. Batching, profiling, and worker sizing. Runtimes down over 50%.
  • Set the CI/CD and testing standard for the team so changes stopped reaching clients unverified. Pytest, ephemeral test environments, Git-based deployment.

Technologies: Python, aiothp, Apache Kafka, Apache Airflow, Elasticsearch, AWS S3, Docker, GitHub Actions

Oct 2017 - Aug 2018
Romania

Software Engineer

Tapptitude

Position summary
Software Engineer at Tapptitude
Industries
Information Technology
Business areas
Information Technology
Product Development

An NLP and AI company building data and training pipelines plus analytics platforms for enterprise clients, often in regulated environments.

  • Wrote the ingestion and export services that moved client source systems into PostgreSQL and BigQuery on a schedule, replacing hand-run scripts. Manual data preparation down about 35%.
  • Built the services that packaged NLP training datasets for the data science team, shaped around what they needed rather than what was easiest to export.
  • Replaced SQL lookup endpoints with an Elasticsearch-backed search and document retrieval service, judged on relevance for the people searching rather than raw query speed.
  • Caught regressions before they reached production in regulated environments, where a wrong number is a compliance problem. Pytest and schema validation wired into CI/CD.

Technologies: Python, FastAPI, PostgreSQL, BigQuery, Elasticsearch, Docker, Azure DevOps

Jun 2016 - Sep 2017

Software Engineer

LiveTiles

Position summary
Software Engineer at LiveTiles
Industries
Information Technology
Business areas
Information Technology
Product Development

An enterprise conversational AI platform automating customer service across chat and voice.

  • Built the services behind the conversation analytics clients used to judge whether the platform was earning its contract: ingestion endpoints, transformation workers, and the reporting API.
  • Kept those endpoints responsive as client data grew. Query and index tuning, connection pooling, and schema design on PostgreSQL and MySQL.
  • Stopped bad data at the service boundary before it reached reporting. Request validation, schema checks, and idempotent writes on every run.

Technologies: Python, FastAPI, PostgreSQL, MySQL, Docker, GitLab CI

Industry experience

See where this freelancer has spent most of their professional time.

Experienced in Information Technology, Banking and Finance, Automotive, and Tourism.

Information Technology
Banking and Finance
Automotive
Tourism
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Business area experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology, Product Development, and Quality Assurance.

Information Technology
Product Development
Quality Assurance
Profile match chart

Summary

Senior Software Engineer with 10 years of full-stack experience across FinTech, enterprise AI, and SaaS. Writes production code in TypeScript, Python, Node.js, and Java, debugging and optimizing complex systems end to end. Owns features from specification through delivery, working across frontend interfaces, backend services, and data layers. Comfortable refactoring legacy codebases, implementing new features with care for performance and maintainability, and documenting technical decisions clearly. Also builds production services and APIs in C#, FastAPI, ASP.NET Core, and NestJS, and has strong remote working habits, including written handovers and reviews.

Skills

  • Languages: Python3, Java, C++, Typescript / Javascript, Sql, Html / Css, C#
  • Software Engineering: Feature Implementation, Codebase Refactoring, Performance Optimization, Bug Fixing And Debugging, Algorithms And Data Structures, Authentication & Authorisation, Retries & Idempotency
  • Frontend: React / Next.Js, Tailwind / Css-In-Js, State Management (Redux, Zustand, React Query), Accessibility (Wcag) & Performance
  • Backend & Services: Node.Js / Nestjs / Express, Fastapi, Asp.Net Core, Rest & Grpc Api Design, Background Workers & Queues, Idempotency & Transactional Writes
  • Ml / Ai Systems: Llm Integration (Claude, Gemini), Entity Resolution / Record Linkage, Human Review Workflows, Model Precision / Error Analysis
  • Pipelines & Orchestration: Dagster, Apache Airflow, Scheduled & Event-Driven Jobs, Ci/Cd For Services & Pipelines
  • Distributed And Streaming: Apache Kafka, High-Throughput Consumers & Worker Pools, Terabyte-Scale Batch Processing, Backpressure, Retries & Idempotency
  • Databases And Warehousing: Postgresql, Mysql, Bigquery, Elasticsearch, Schema Design & Migrations, Query Optimization
  • Testing: Jest / Vitest, Playwright / Cypress, Pytest, Contract Testing
  • Cloud And Devops: Google Cloud (Cloud Run, Cloud Sql, Cloud Storage, Iam), Aws (S3), Docker, Github Actions / Gitlab Ci / Azure Devops
  • Product And Domain: Requirements Analysis For Backend Systems, Spec Review & Clarification, Stakeholder Facilitation, Data & Service Cost Ownership, M&A And Fintech Domain

Languages

Romanian
Native
English
Advanced

Education

Sep 2019 - Oct 2021

Institute of Technology Sligo

Mathematics and Computer Science · Sligo, Ireland

Sep 2012 - Jun 2016

Institute of Technology Sligo

Bachelor's degree · Computer Science · Sligo, Ireland

Statistics

Experience

Total positions 5
Experience in Information Technology 10 y
Avg length 2 y
Longest experience 4 y 9 m

Global experience

Countries worked in 3 (Germany, United States, Romania)
Primary country Germany

Expertise

Recent roles Senior Backend Engineer, Senior Platform Engineer, Platform Engineer
Main industries Information Technology, Banking and Finance, Automotive
Main business areas Information Technology, Product Development, Quality Assurance

Qualifications

Highest degree Master

Profile

Member since
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Frequently asked questions

Have questions? Find more information here.

Daniel is based in Tulcea, Romania and prefers 100% remote projects.

Daniel speaks the following languages: Romanian (Native), English (Advanced).

Daniel has at least 10 years of experience. During this time, Daniel has worked in at least 4 different roles and for 4 different companies. The average length of individual experience is 2 years. Note that Daniel may not have shared all experience and actually has more experience.

Based on recent experience, Daniel would be well-suited for roles such as: Senior Backend Engineer, Senior Platform Engineer, Platform Engineer.

Daniel's most recent position is Senior Backend Engineer at Datasite.

In recent years, Daniel has worked for Datasite and Cognigy.

Daniel is most experienced in industries like Information Technology, Banking and Finance, and Automotive. Daniel also has some experience in Tourism.

Daniel is most experienced in business areas like Information Technology, Product Development, and Quality Assurance.

Daniel has recently worked in industries like Information Technology, Banking and Finance, and Automotive.

Daniel has recently worked in business areas like Information Technology, Product Development, and Quality Assurance.

Daniel holds a Master in Mathematics and Computer Science from Institute of Technology Sligo and a Bachelor in Computer Science from Institute of Technology Sligo.

Daniel is immediately available full-time for suitable projects.

Daily rate distribution

0% 25% 50% 75% 100%
11% of experts charge less than €320 per day.
33% of experts charge between €320 and €400 per day.
22% of experts charge between €400 and €480 per day.
11% of experts charge between €560 and €640 per day.
22% of experts charge €720 or more per day.
<€320 €320-​400 €400-​480 €560-​640 €720+

The rates shown represent the typical market range for freelancers in this position based on recent contracts on our platform.

Average rates for similar positions

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

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Daily rate avg. 440 €

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

600
450
300
150
Rate comparison chart
Median rate 400 €

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 3 Oct 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.