Custom LLM development services, tuned to your domain
Language models fine-tuned on your data and deployed where your policies require, cloud or on-premise, by senior nearshore engineers in your time zone.
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15+years delivering software
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100+senior engineers across LATAM
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6-8hdaily overlap with US teams
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6+Fortune 500 & global brands trust us
Language models that know your business
A general model knows the internet. Yours needs to know your products, your policies, and your customers.
FusionHit builds and fine-tunes language models on your own data, running in your cloud or on your servers, with senior nearshore engineers in your time zone.
Our LLM development services
From choosing the right model to running it on your terms.
Custom LLM development
Build a language model around your domain, your data, and the tasks your team actually does.
LLM fine-tuning
Adapt an open or commercial model to your terminology, tone, and edge cases.
Private LLM deployment
Run models in your cloud or on-premise, so sensitive data never leaves your perimeter.
LLM integration
Connect models to your product, APIs, and data through clean, maintainable interfaces.
LLM evaluation
Benchmark accuracy, cost, and safety across models before you commit to one.
LLM consulting
Pick the right model, approach, and budget for your use case before development starts.
General-purpose, fine-tuned, or private?
Three ways to run a language model, with real trade-offs. Here's the honest comparison.
Fast start, broad tasks
Domain language and consistency
Sensitive or regulated data
Sent to the provider
Used to train your version
Never leaves your perimeter
Lowest
Moderate
Highest
Per token
Per token, fewer tokens needed
Infrastructure, predictable at scale
Provider's roadmap
Yours, on their platform
Fully yours
Signs you need a private model
Some workloads cannot run on a public API. These are the usual reasons.
Regulated data
HIPAA, financial, or personal data that cannot leave your environment.
Data residency
Contracts or regulations that require processing in a specific country or cloud.
Proprietary knowledge
Internal documents and IP you will not send to a third-party provider.
Cost at scale
High-volume inference where per-token pricing stops making sense.
Why companies build their LLMs with us
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Senior AI engineers
Engineers who have fine-tuned and deployed language models in production, not just called an API.
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Model-agnostic
We recommend open or commercial models on fit, accuracy, and cost, with no vendor stake.
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Your data stays yours
Your data trains only your model, with private deployment when your policies require it.
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Real-time collaboration
Nearshore engineers on US hours, live in your standups, reviews, and evaluations.
Language models we've shipped
Making 130,000 Financial Documents Searchable with AI
Challenge A financial operations team was spending 2–3 hours per search session manually navigating complex document repositories — scanned PDFs, spreadsheets,…
Embedding AI Across the Full Engineering Lifecycle
Challenge A product engineering team was managing growing codebases with increasing complexity around quality control, documentation, and cloud infrastructure. Code reviews…
AI-Augmented Development and Operations in a Multi-Team Enterprise
Challenge Multiple engineering teams working across Supply Chain and Support Services were operating in silos, each dealing independently with challenges around…
The models and tools we build with
Open and commercial models, plus the tooling that makes them production-ready.
Open models
- • Llama
- • Mistral
- • Qwen
- • Gemma
Commercial models
- • OpenAI (GPT)
- • Anthropic (Claude)
- • Google (Gemini)
Tooling
- • Hugging Face
- • LangChain
- • LlamaIndex
- • vLLM
- • LoRA
Infrastructure
- • AWS
- • Azure
- • Google Cloud
- • Kubernetes
- • On-premise GPU
LLMs for your industry
Where a model that knows your domain changes the work.
Fintech
Document analysis, risk narratives, and support, inside your compliance perimeter.
Healthcare
Clinical and administrative language tasks on HIPAA-compliant infrastructure.
Insurance
Policy, claims, and underwriting language trained on your own documents.
SaaS
Product copilots and in-app intelligence tuned to your feature set.
Logistics
Document processing and exception handling across supply chain paperwork.
Retail
Product content and customer conversations in your brand voice.
Engage an LLM team the way that fits
Add senior AI engineers to your team, embed a dedicated team, or hand us the full build. Pick the model that fits how you work today.
Add AI engineers to your team
Senior nearshore AI engineers join your existing team, under your direction, in days, not months.
Embed a dedicated AI team
A stable, cohesive team that works only on your model and product as an extension of yours. You set priorities and roadmap, the team self-organizes sprint after sprint.
Hand us the full build
Hand us the roadmap and we deliver end to end, under our direction: model selection, training, evaluation, and deployment. You get an outcome, not a team to manage.
How we build your model, in your time zone
FAQs about our LLM development services
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How much does custom LLM development cost?
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Should we fine-tune a model or use RAG?
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Can we run a model on our own servers?
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Which models do you work with?
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How do you measure whether the model is good enough?
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Who owns the model and the data?
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How long does it take to build a custom LLM?
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How is this different from generative AI development?
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Do you help run the model after launch?
Ready to build a model that knows your business?
Tell us the task you want a model to handle, and we'll show you the fastest path to it.
Trusted by leading teams
Rated by our clients
