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
41

Mercury 2

Inception
Text & chatMultilingualProprietary API
$0.25 / $0.75128K tokensAPI only0.75View
42

Trinity Large Thinking

Arcee Ai
Text & chatReasoningTool calling
$0.25 / $0.8262.1K tokensAPI only0.8View
43

Mistral Large 3 2512

Mistral AI
Text & chatVisionReasoning
$0.5 / $1.5262.1K tokensAPI only1.5View
44

Devstral 2 2512

Mistral AI
Text & chatCodingStructured JSON output
$0.4 / $2262.1K tokensAPI only2View
45

GPT-5.4

OpenAI
Text & chatVisionReasoning
$2.5 / $151.05M tokensAPI only15View
46

GPT-5.3-Codex

OpenAI
Text & chatVisionCoding
$1.75 / $14400K tokensAPI only14View
47

GPT-Realtime-2.1

OpenAI
Text & chatVisionAudio
$4 / $24128K tokensAPI only24View
48

GPT-Realtime-2.1 Mini

OpenAI
Text & chatVisionAudio
$0.6 / $2.4128K tokensAPI only2.4View
49

Gemini 3.1 Flash-Lite

Google
Text & chatVisionAudio
$0.25 / $1.51.05M tokensAPI only1.5View
50

Nano Banana 2

Google
VisionImage generationStructured JSON output
API onlyView
51

Nano Banana 2 Lite

Google
VisionImage generationStructured JSON output
API onlyView
52

Nano Banana Pro

Google
VisionImage generationStructured JSON output
$2 / $12API only12View
53

Gemini Omni Flash

Google
Text & chatVisionAudio
$1.5 / $9API only9View
54

Gemini 3.5 Transcribe

Google
AudioAdjustable thinkingSpeech-to-text
API onlyView
55

Gemini 3.5 Transcribe Live

Google
AudioAdjustable thinkingSpeech-to-text
API onlyView
56

Grok 4.20 Reasoning

xAI
Text & chatVisionReasoning
$1.25 / $2.51M tokensAPI only2.5View
57

Grok 4.20 Non-Reasoning

xAI
Text & chatVisionReasoning
$1.25 / $2.51M tokensAPI only2.5View
58

Grok Build 0.1

xAI
Text & chatAdjustable thinkingWeb search grounding
$1 / $2256K tokensAPI only2View
59

Codestral

Mistral AI
Text & chatCodingStructured JSON output
$0.3 / $0.9128K tokensAPI only0.9View
60

Devstral 2

Mistral AI
Text & chatCodingStructured JSON output
256K tokensAPI onlyView

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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