Daniel F.-Senior Backend Engineer
Check rate
Experience
Senior Backend Engineer
Datasite
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
Senior Platform Engineer
Cognigy
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
Platform Engineer
Cognigy
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
Software Engineer
Tapptitude
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
Software Engineer
LiveTiles
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.
Business area experience
See which departments and functions this freelancer has contributed to most.
Experienced in Information Technology, Product Development, and Quality Assurance.
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
Education
Institute of Technology Sligo
Mathematics and Computer Science · Sligo, Ireland
Institute of Technology Sligo
Bachelor's degree · Computer Science · Sligo, Ireland
Statistics
Experience
Global experience
Expertise
Qualifications
Profile
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.
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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.
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