Proprietary AI models: API-only, and what that locks you into

Proprietary API
Services found: 151
#AI modelCapabilitiesAPI $/1M (in / out)Context windowPrice / moOutput $/1MOverviewVisit site
141

MiMo-V2.6-Pro

Xiaomi
Text & chatVisionAudio
$0.435 / $0.871M tokensAPI only0.87View
142

MiMo-V2.6-Flash

Xiaomi
Text & chatVisionAudio
$0.14 / $0.281M tokensAPI only0.28View
143

MiMo-V2.6-Pro-UltraSpeed

Xiaomi
Text & chatVisionAudio
$4.35 / $8.71M tokensAPI only8.7View
144

Fugu Max

Sakana
Text & chatReasoningAdjustable thinking
$2 / $6API only6View
145

Aion 3.5

Aion Labs
Text & chatReasoningPrompt caching
$3 / $6256K tokensAPI only6View
146

Aion 3.5 Mini

Aion Labs
Text & chatReasoningPrompt caching
$0.7 / $1.4256K tokensAPI only1.4View
147

Solar Mini 4

Upstage
Text & chatReasoningAdjustable thinking
$0.1 / $0.4512K tokensAPI only0.4View
148

Perceptron Mk1.5

Perceptron
Text & chatVisionAudio
$0.15 / $1.536.9K tokensAPI only1.5View
149

Pareto

Unbiased
Text & chatVisionPrompt caching
$0.8 / $3.2API only3.2View
150

Schematron V2 Turbo

Inference.net
Text & chatStructured JSON outputPrompt caching
$0.03 / $0.15125K tokensAPI only0.15View
151

Schematron V2 Small

Inference.net
Text & chatStructured JSON outputPrompt caching
$0.05 / $0.23125K tokensAPI only0.23View

Browse by need

These 151 models are available only through the vendor own API: no weights to download, no self-hosting, no fine-tuning beyond what the vendor exposes. In exchange you get no infrastructure to run and immediate access to whatever ships next.

Prices run from $0.87 to $50 per million output tokens. The frontier tier is entirely proprietary - GPT-6 Astra, Claude Fable 5.1, Claude Opus 5 - and that gap is the honest argument for closed models. The arguments against are equally practical: pricing changes without your consent, models get retired on the vendor schedule, and your data leaves your perimeter.

No infrastructureNothing to provision, patch or scale — the vendor absorbs all of it.
The frontier lives hereEvery top-quality model today is closed. There is no open equivalent yet.
Vendor risk is realPrices change, models retire, and your data crosses a boundary.

Models with this capability

How to choose

  • Check the deprecation policy before building on a specific model version.
  • Pin snapshot versions where the vendor offers them, rather than floating aliases.
  • Read the data-retention terms if you handle personal or regulated information.
  • Keep an open-weight fallback identified, even if you never use it.

Common mistakes

Building on a floating aliasA silent model update can change behaviour overnight.
No exit planTeams discover lock-in at the moment prices rise, not before.

Who this suits

Small teamsNo GPU budget, no ops capacity, immediate access to the best models.
EnterprisesCompliance certifications and support contracts that self-hosting cannot match.
PrototypingValidating an idea before committing infrastructure.

Frequently asked questions

Why choose a closed model?

The frontier tier is entirely proprietary. If you need the best available quality, there is no open alternative yet.

What are the risks?

Pricing changes without your consent, models get retired on the vendor schedule, and your data leaves your perimeter.

What is the open alternative?

90 models in this rating publish weights — GLM, Qwen, DeepSeek, Mistral, Gemma and others.

Can I fine-tune a proprietary model?

Sometimes, within the vendor platform. You never receive the weights.

What happens when a model retires?

You migrate. Vendors publish timelines, but the work lands on you.

Frequently searched

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