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LLM Integration Services —
From Prototype to Production

We integrate large language models into your existing software — APIs, databases, internal tools — and ship to production. No boilerplate starters. LLM integration consulting that works with your stack, not against it.

What we integrate

End-to-end large language model integration across four domains. Each engagement is scoped to what your product actually needs.

RAG & Knowledge Systems

Connect your documents, databases and internal wikis to an LLM via retrieval-augmented generation. Accurate answers grounded in your data — no hallucinations, no stale context.

  • Vector search with pgvector or Weaviate
  • Chunking, embedding & reranking pipelines
  • Hybrid BM25 + semantic retrieval
  • Incremental indexing & refresh

LLM into Existing APIs

Integrate LLM capabilities into your current backend without a rewrite. We wire the model as a service layer your existing endpoints call — typed, versioned, observable.

  • Structured output & JSON mode
  • Tool use / function calling
  • Streaming responses
  • Rate limiting & fallback routing

Fine-tuning & Prompt Engineering

When off-the-shelf prompting isn't enough: systematic prompt optimization, few-shot dataset curation and supervised fine-tuning on domain-specific corpora.

  • Prompt audit & optimization
  • Evaluation suite (evals) setup
  • LoRA / QLoRA fine-tuning
  • RLHF-adjacent preference data

Multi-model Orchestration

Route tasks to the right model at the right cost. Build agent pipelines where models collaborate, tools execute and outputs are validated before reaching users.

  • LangChain & LlamaIndex pipelines
  • Provider fallback & cost routing
  • Agent loops with tool use
  • Guardrails & output validation

How we work

Four stages. No surprises. Every LLM integration engagement follows the same disciplined path from discovery to live system.

01 / audit

Audit

We map your current stack, data sources and pain points. Output: a clear scope doc with what's feasible, what it costs and what to skip.

  • Stack & data inventory
  • Use-case prioritization
  • Risk & latency assessment
02 / architecture

Architecture

We design the integration: model choice, retrieval strategy, prompt structure, context management and the monitoring layer before writing a line of code.

  • Model & provider selection
  • Data flow diagrams
  • Eval criteria defined
03 / integration

Integration

We build against your existing codebase. Typed clients, streaming where it helps, structured output, test coverage and a working eval suite.

  • Production-grade code
  • Automated evals
  • API docs & runbooks
04 / deploy & monitor

Deploy & Monitor

Ship with observability from day one: latency tracking, cost dashboards, error rates and a feedback loop so the system improves after launch.

  • Canary & rollout plan
  • Latency & cost dashboards
  • Regression monitoring

What we use

No stack fetishism. We work with whatever your team already runs and add the LLM layer that fits.

LLM Providers

  • OpenAIGPT-4o, o3, embeddings
  • AnthropicClaude 3.x / 4.x
  • GoogleGemini 2.x Flash & Pro
  • MistralMistral Large, Codestral
  • MetaLlama 3.x (self-hosted)
  • CohereCommand R+, Embed

Orchestration & Frameworks

  • LangChainchains, agents, tools
  • LlamaIndexRAG, query engines
  • Instructorstructured output
  • DSPyoptimized prompting
  • Pydantic AItyped agents

Vector & Retrieval

  • pgvectorPostgres-native
  • Weaviatehybrid search
  • Qdrantself-hosted
  • Pineconemanaged
  • OpenSearchBM25 + kNN

Observability

  • LangSmithtraces & evals
  • Langfuseself-hosted OSS
  • Prometheuslatency & cost
  • OpenTelemetryinstrumentation

Infrastructure

  • Dockercontainerized deploy
  • FastAPI / HonoAPI layer
  • Celery / BullMQasync jobs
  • Rediscaching & queues
  • AWS / GCP / Fly.io

Fine-tuning

  • OpenAIsupervised FT
  • UnslothLoRA / QLoRA
  • Axolotlmulti-GPU
  • W&Bexperiment tracking

Frequently asked questions

What is LLM integration?

LLM integration is the process of connecting a large language model — GPT-4o, Claude, Mistral or an open model — to your existing software so it can read context, take actions and return useful output. It's more than calling an API: you need to design prompts, manage context windows, handle retrieval, deal with latency and build guardrails before you have something reliable in production.

How do you integrate an LLM into existing software?

We start with an audit of your current stack and data flows. Then we design the integration architecture — choosing the right model, deciding how to pass context and where to add retrieval. We implement against your existing APIs and databases, write automated evals and set up monitoring. Every project follows the same path: Audit → Architecture → Integration → Deploy & Monitor.

What's the difference between RAG and fine-tuning?

RAG (Retrieval-Augmented Generation) retrieves relevant documents at query time and injects them into the prompt — no retraining, data stays fresh, fast to iterate. Fine-tuning updates the model weights on your data — better for stable style, tone or narrow domain tasks where the training corpus doesn't change often. Most production systems start with RAG. Fine-tuning is added when RAG alone can't close the quality gap.

How long does LLM integration take?

A focused integration — one feature, one model, existing API — typically takes 2–4 weeks from audit to first production deploy. Full RAG pipelines with custom retrieval and monitoring land in 4–8 weeks. Timeline depends on data readiness, access to your codebase and how many approval cycles your organization needs.

Do you work with any LLM provider?

Yes. We work with OpenAI, Anthropic, Google, Mistral, Meta (Llama), Cohere and self-hosted open models. We help you choose the right model for cost, latency and capability, and design the integration so you can swap providers without rewriting your application logic.

What does LLM integration cost?

Project-based engagements start at $8,000 USD for a scoped integration. Ongoing consulting retainers are available for teams that need recurring architecture support, prompt engineering and model evaluations. Write to hola@luz.uy with a brief description of your use case and we'll send a scoped proposal within 48 hours.

Ready to wire AI into your stack?

Tell us what you're building. We'll scope it and get back within 48 hours.

hola@luz.uy