Mustafa Bayer
Available for consulting

Production-grade software
for the AI era

From LLMs, RAG and agentic systems to mobile apps and backend architectures β€” I turn ideas into scalable, reliable products. Backed by years of hands-on engineering and consulting.

Let's work together β†’ What I do
About

A consultant who ships code

Hi, I'm Mustafa Bayer. I've been building software and consulting for companies for many years. My focus is modern AI systems: large language models (LLMs), fine-tuning with LoRA, Qdrant-based vector search, chatbots and agentic RAG architectures.

Alongside that, I build end-to-end products β€” mobile apps with Kotlin, Swift and Flutter, REST APIs with Python, and modern web UIs with Vite.js. I work across every layer, from prototype to production.

Whether you're starting an AI product from scratch or scaling an existing system, I bring engineering discipline and practical solutions.

Areas of Expertise

From AI to mobile, end to end

I combine modern AI systems with solid engineering practices.

🧠

LLM & Fine-tuning

LLM integration, prompt engineering and domain-specific fine-tuning with LoRA.

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RAG & Vector Search

Qdrant-based retrieval-augmented generation; accurate, source-grounded, up-to-date answers.

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Agentic Systems

Tool-using, multi-step reasoning agentic RAG and chatbot architectures; autonomous workflows.

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Mobile Development

Performant, native-feeling cross-platform apps with Kotlin (Android), Swift (iOS) and Flutter.

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Backend & API

Scalable REST APIs, microservices and AI model-serving infrastructure with Python.

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Modern Web

Fast, elegant and responsive UIs with Vite.js and the modern JavaScript ecosystem.

In-Depth Capabilities

End-to-end AI engineering

From models to infrastructure, security to evaluation β€” I address each layer on its own. Click a heading to expand the details.

🧠LLMs & Transformer Architecturesβ–Ό
LlamaGemmaQwenMistral GPT / decoder-onlyBERTRoBERTaDistilBERT DeBERTaT5 / encoder-decoderSentence Transformers Turkish & multilingual NLPModel selection & architecture analysis

Not every problem needs a generative model. For text classification, intent detection, entity extraction and similarity I use smaller, faster BERT-based models β€” a BERT classifier for intent, an embedding model for retrieval and an LLM for generation, working together to balance cost, latency and accuracy.

🎯Model Training & Customizationβ–Ό
SFTLoRAQLoRAPEFT Instruction tuningTool/function calling dataDomain adaptation Synthetic dataData cleaning & qualityTrain/val/testBehavior measurement

In fine-tuning I focus less on training the model and more on identifying the right training problem: RAG for fresh knowledge, fine-tuning for behavior and task discipline, tool calling for real-time actions β€” treated as complementary layers that solve different problems, not alternatives.

⚑Model Serving & Inference Infrastructureβ–Ό
vLLMOpenAI-compatible APIHF TransformersTGI Ollamallama.cppONNX RuntimeStreaming Continuous batchingKV cachePrefix/prompt caching Tensor/pipeline parallelismMulti-GPUHorizontal scaling

I serve open-source models at high concurrency with engines like vLLM, using continuous batching, PagedAttention and KV cache management to make GPUs efficient. I focus not just on the model running, but on time-to-first-token, tokens/sec, GPU memory, concurrent request capacity and cost per request.

πŸ—œοΈModel Compression & Performanceβ–Ό
8-bit / 4-bit quantizationAWQGPTQbitsandbytes GGUFFlash AttentionDistillationSpeculative decoding Model routingContext optimizationVRAM reductionLatency/throughput

Instead of using the largest model for everything, I build systems that route tasks to different models by complexity: simple classification on small models, complex reasoning on large ones. This routing lowers cost while improving latency and scalability.

πŸ”ŽRAG & Enterprise Knowledge Systemsβ–Ό
RAGAgentic RAGQdrantDense/sparse/hybrid BM25Semantic searchMetadata filteringMulti-vector Parent-child retrievalQuery expansion/rewritingHyDE Contextual retrievalMulti-queryDocument authorizationSource citation

Chunking documents into a vector database is never enough on its own. Based on a document's structure, headings, tables and semantic coherence I apply semantic chunking, recursive splitting, parent-child relationships and type-specific parsing strategies.

🧭Embeddings & Semantic Searchβ–Ό
Dense/sparse embeddingsSentence TransformersBGEE5 Turkish & multilingualBenchmarkingCosine/dot/EuclideanMetadata filtering Collection/index designDimension/performanceDomain-specific fine-tuning

I evaluate embedding models not by specs alone but by retrieval success on real data. By measuring how highly the correct document ranks, I jointly optimize the model, chunking structure and index settings.

πŸ“ŠReranking & Result Qualityβ–Ό
Cross-encoder rerankersBERT rerankingBGE Reranker LLM relevanceTwo-stage retrievalTop-k optimizationContext compression

A fast embedding model retrieves a broad set first; a cross-encoder or BERT-based reranker re-orders them in a second stage. This significantly improves answer accuracy in enterprise systems full of near-duplicate documents.

πŸ€–Agentic Systems & Tool Callingβ–Ό
Function callingREST/service integrationMulti-step planning Agent orchestrationTool selection/routingSchema validation State machine flowsHuman-in-the-loopAgent memoryError recoveryMulti-agent

Rather than giving a model unlimited authority, I explicitly define the allowed tools and operational boundaries. For critical actions β€” money transfers, record deletion, database updates β€” I build guardrails: user verification, authorization checks, parameter validation and explicit approval.

πŸ’¬Natural Language Processingβ–Ό
Intent classificationNERText classificationSentiment analysis Topic extractionText similarityInformation extractionQuestion answering SummarizationMultilingualTurkish morphology

I use BERT and its variants for tasks needing low latency and high consistency, extracting person, date, amount, product and action type from a message into structured business data β€” e.g. "invoice five pens to HΓΌseyin" is parsed into customer, product, quantity and action type, then safely passed to the accounting service.

🧱Structured Data Generationβ–Ό
JSON SchemaPydanticStructured outputsGrammar-constrained generation Type-safe tool paramsMissing-param detectionAuto-retryNL β†’ business objects

Instead of turning model output directly into an application action, I insert schema validation and business-rule checks in between. The data types, required values and allowed bounds of generated fields are verified before any action runs.

✍️Prompt & Context Engineeringβ–Ό
System prompt designFew-shot / zero-shotPrompt templates Dynamic contextConversation memoryContext window optimization Prompt versioningPrompt injection defenseData maskingPrompt routing

Rather than scattering prompts uncontrolled through application code, I treat them as a versioned, testable and measurable part of the system.

πŸ“LLM Evaluation & Qualityβ–Ό
Precision / recallHit RateMRRnDCG FaithfulnessGroundednessAnswer/context relevanceHallucination analysis Tool calling accuracyRegression testsGolden datasetA/B testingLLM-as-a-judge

I assess quality not with a handful of sample questions but with test sets that represent real usage, comparing the impact of model, prompt, embedding, reranker and retrieval changes through measurable metrics.

πŸ“‘LLMOps, Observability & Monitoringβ–Ό
Prompt/model versioningToken & cost analysisRequest/response tracing Tool call tracingLatency measurementError rateGPU/CPU/memory monitoring Drift analysisCentralized loggingAuditProduction debugging

In a production AI system, it must be traceable which model, with which prompt version, using which documents, called which tools. That traceability is critical both for debugging and for understanding how each answer was produced.

πŸ›‘οΈSecurity & AI Governanceβ–Ό
Prompt injection / jailbreak preventionTool/API authorizationRBAC Tenant isolationPII detection & maskingOutput filteringContent safety Audit loggingHuman approvalSafe fallback

In enterprise and multi-tenant systems, to ensure one user can never reach another company's data I enforce access control not just at the prompt level but across the API, database, retrieval and authorization layers.

πŸ—οΈAI System Architectureβ–Ό
Hybrid small+large modelsModel gatewayLocal + cloud models Fallback / failoverTask-based routingEvent-driven workflows Message queueMicroservice / modular monolithStateless/stateful agents Cache / rate limit / retryMulti-tenant AI platform

My goal is not just an LLM integration but designing the AI layer as a scalable, sustainable system that works alongside the rest of the application. In one project, BERT intent classification, Qdrant retrieval, cross-encoder reranking, an open-source model on vLLM and Python REST APIs can run together in the same architecture β€” with no lock-in to a single model or provider.

Selected Work

Projects & Case Studies

The cards below are placeholders β€” ready to be filled with your real projects.

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Enterprise RAG Assistant

Source-citing agentic RAG chatbot over company documents. Qdrant + LLM + tool use.

Agentic RAGQdrantPython
Details β†’
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Cross-Platform Mobile App

AI-powered mobile app built with Flutter, backed by a Python REST API.

FlutterKotlinREST API
Details β†’
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Custom LLM Fine-tuning

Domain-specific LLM fine-tuned with LoRA β€” self-hosted and cost-efficient.

LoRAFine-tuningSelf-hosted
Details β†’
Services

How can I help?

Flexible engagement models β€” from one-off consulting to end-to-end product development.

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AI Product Development

I take your chatbot, RAG assistant or custom LLM solution from idea to production.

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Technical Consulting

Strategic guidance on architecture, tech selection, cost optimization and code quality.

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Mobile & Web Apps

Mobile and web development that turns your idea into a real product in users' hands.

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Training & Mentoring

Hands-on training for your teams on LLMs, RAG and modern development practices.

Tech Stack

Technologies I work with

AI & ML

LLMLoRAFine-tuning QdrantAgentic RAGChatbot Vector SearchPrompt Engineering

Mobile

KotlinSwiftFlutter AndroidiOS

Backend & Web

PythonREST APIVite.js JavaScriptMicroservices

Let's build something together

Have a project, a question, or just an idea? Reach out β€” I'd love to talk.

βœ‰οΈ mustafa.bayer@outlook.com