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Custom LLM Development

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Custom LLM Development

Project Overview

We developed a custom, domain-tuned large language model for a client with strict data-privacy needs — delivering expert-level performance on their specialized tasks while keeping all data inside their own infrastructure.

The Challenge

General-purpose APIs could not match the client's domain terminology and could not be used at all for their most sensitive data, which had to stay on-premise for compliance.

  • Generic models misunderstood domain-specific language
  • Sensitive data could not leave client infrastructure
  • API costs scaled painfully with volume
  • No control over model updates or behavior

Our Strategic Approach

We curated a domain dataset, fine-tuned an open-weight base model, and deployed it privately with an inference stack the client fully controls, plus an evaluation harness to prove quality.

The Solution We Delivered

The result is a private, domain-expert LLM running in the client's environment, served through an internal API with monitoring and a clear retraining path.

  • Domain-tuned model on curated proprietary data
  • Fully private, on-premise or VPC deployment
  • Internal API with autoscaling inference
  • Evaluation harness proving task quality
  • Guardrails and safety filtering
  • Documented retraining and versioning path

Technologies Used

  • Open-weight base LLMFoundation for fine-tuning
  • LoRA / PEFTEfficient domain fine-tuning
  • vLLMHigh-throughput private inference
  • PyTorchTraining and evaluation
  • KubernetesScalable private deployment
  • Weights & BiasesExperiment tracking and evals

Development Process

  1. Data curationAssembled and cleaned a high-quality domain dataset.
  2. Fine-tuningTuned the base model efficiently with PEFT methods.
  3. EvaluationBuilt task-specific evals to validate quality and safety.
  4. Private deploymentDeployed the inference stack inside client infrastructure.
  5. Monitoring & handoverSet up monitoring and a documented retraining path.

Results & Impact

The custom model outperformed general APIs on the client's tasks while keeping data fully private and costs predictable.

  • Domain-task accuracy exceeded general-purpose APIs
  • All sensitive data kept on client infrastructure
  • Per-query cost reduced at the client's volume
  • Full control over updates, behavior, and safety

🎯 Key Takeaway

A custom, privately deployed LLM gave the client domain-expert AI on their own terms — accurate, compliant, controllable, and cost-effective at scale.

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Frequently Asked Questions

What is custom LLM development?
It is building or fine-tuning a large language model on your domain data and deploying it under your control, so it understands your terminology and meets your privacy needs.
Can the model run on our own infrastructure?
Yes. We deploy privately — on-premise or in your VPC — so sensitive data never leaves your environment.
Why not just use a general API?
A domain-tuned, private model can outperform general APIs on specialized tasks, keep data in-house for compliance, and offer more predictable costs at scale.
How do you prove it is good enough?
We build a task-specific evaluation harness to measure quality and safety against your real requirements before launch.
Can it be updated later?
Yes. We provide a documented retraining and versioning path so the model evolves with your needs.
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