2026-04-15

Public LLM, API or self-hosted model: which is right for your business?

Putting a language model into a business process involves a structural architecture choice — one that will determine your costs, your confidentiality level and your room for maneuver for years. Three options dominate, each with its strengths and trade-offs.

Three architectures: public tool, API, model hosted on your premises

Option 1: public tools (consumer chatbots)

Fast to adopt, no integration: every employee just opens a browser and works. That's also their limit — AI stays next to your processes, never inside them.

  • For: zero entry cost, discovering use cases, team awareness.
  • Against: no integration with your systems, no traceability, risk of leaking confidential data, results that vary from one employee to the next, nothing capitalized.

Verdict: useful for awareness and generic tasks on public data. Insufficient for a business process.

Option 2: proprietary model APIs

Your applications call a vendor's model through an API. This is the fastest route to real integration: the model slots into your workflows, under your rules.

  • For: state-of-the-art quality, instant scalability, no infrastructure to manage, fast iteration.
  • Against: your data passes through a third party (with contractual guarantees that vary by offer), per-request costs that grow linearly with usage, dependency on the vendor's pricing and technical roadmap.

Verdict: relevant for fast prototyping and value validation, and for moderate volumes on low-sensitivity or properly pseudonymized data.

Option 3: a model hosted on your premises

An open model deployed on your servers or private cloud, integrated with your tools. This is the "your AI, custom-built, at home" option.

  • For: your data never leaves, fixed and predictable costs at high volume, deep customization (vocabulary, rules, internal documents), vendor independence, simplified compliance (no processor to contract).
  • Against: higher initial investment, requires deployment and monitoring skills — in-house or supported.

Verdict: the right choice as soon as data is sensitive, volumes are steady, or AI becomes a durable component of your processes.

The comparison at a glance

CriterionPublic toolProprietary APIHosted on-premises
ConfidentialityLowMedium (contractual)Maximum
Cost at low volumeNoneLowMedium
Cost at high volumeHigh and growingFixed and predictable
Integration with your toolsNoneGoodTotal
CustomizationNoneLimitedDeep
Vendor dependencyHighHighLow
Time to deployImmediateWeeksWeeks to months

The questions that settle it

  1. What happens if this data leaks? If the answer hurts (customer data, health, HR, trade secrets), self-hosting is the answer for that scope.
  2. What volume at 12 months? Estimate API costs at target volume — not pilot volume. The economic tipping point often arrives sooner than expected.
  3. Is AI a test or a durable component? You don't build a core process on a dependency you don't control.
  4. Who will operate the system? Without internal skills or a partner, poorly maintained self-hosting becomes a risk of its own.

In practice: a hybrid trajectory

Most companies benefit from combining: prototype on APIs to validate value quickly, then migrate validated, sensitive processes to an internally hosted model. Generic, low-stakes uses can stay on APIs.

The key is designing the integration from day one so this migration stays possible: an abstraction layer between your applications and the model, standard exchange formats, and test suites that let you compare models objectively. That's an architecture choice, not luck — and it's exactly the kind of decision worth making before the first project, not after the tenth.

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