AI Models · Open-Source vs Paid

Mistral Medium 3.5 Open vs AIAion 3.5 Paid

Mistral Medium 3.5 vs Aion 3.5 compared — price per token, context window, multimodality, openness and which to choose. Can the open-source model replace the paid one? Full 2026 breakdown.

Aion 3.5 — full profile ›

Prices & specs refreshed from live data · olud.ai

Open-model prices = cheapest provider via OpenRouter; official maker rates may be higher.

Mistral Medium 3.5OpenMistral AI

$1.5 /M input
$7.5 /M outputNo per-token fees if you self-host

TypeOpen-weight

Context window262K tokens

MultimodalYes

Self-hostYes

AIAion 3.5PaidAionLabs

$3 /M input
$6 /M outputManaged API (no infra to run)

TypeProprietary

Context window262K tokens

MultimodalNo

Self-hostNo

Choose Mistral Medium 3.5 if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose Aion 3.5 if you want frontier capability through a managed API with zero infrastructure to run.

Mistral Medium 3.5 vs Aion 3.5 specs

Spec	Mistral Medium 3.5	Aion 3.5	Winner
Maker	Mistral AI	AionLabs	–
Type	Open-weight	Proprietary	Mistral Medium 3.5
Context window	262K tokens	262K tokens	= Tie
Input price	$1.5/M · free self-host	$3/M	Mistral Medium 3.5
Output price	$7.5/M · free self-host	$6/M	AIAion 3.5
Vision / multimodal	Yes	No	Mistral Medium 3.5
Tool / function calling	Yes	Yes	= Tie
Self-hostable	Yes	No (API only)	Mistral Medium 3.5
License	Apache 2.0	Proprietary	Mistral Medium 3.5

Price gap & when to choose each

Choose Mistral Medium 3.5 if…

You want to self-host or run on your cloud
You prioritize data privacy & control
You are building open or reproducible AI

AIChoose Aion 3.5 if…

You want frontier performance through a managed API
You want the lower output price
You value reliability & ecosystem
You don't want to manage infrastructure

Feature comparison

Capability	Mistral Medium 3.5	Aion 3.5
Open weights (downloadable)	✓	✗
Self-hostable	✓	✗
Runs fully offline	✓	✗
Vision / multimodal	✓	✗
Tool / function calling	✓	✓
1M+ context window	✗	✗

Benchmarks: Mistral Medium 3.5 vs Aion 3.5

Independent benchmark scores measured by Artificial Analysis. Higher is better (except latency).

Mistral Medium 3.5

Aion 3.5

Intelligence index

14.2

–

Coding index

46.9

–

GPQA

74.8%

–

Humanity's Last Exam

13.8%

–

Long Context Reasoning

69.3%

–

SciCode

40.2%

–

IFBench

68.8%

–

τ²-Bench

94.2%

–

τ-Bench Banking

15.1%

–

Terminal-Bench

50.6%

–

Terminal-Bench Hard

33.3%

–

Speed

154.2 tok/s

–

Latency

0.69s

–

Intelligence per $

4.7

–

Benchmark data by Artificial Analysis.

How Mistral Medium 3.5 and Aion 3.5 score

🏆 Best value & openness: Mistral Medium 3.5 (4.6 vs 2.8 / 5)

Criterion	Mistral Medium 3.5	Aion 3.5
Cost-efficiency	4.0	4.0
Context window	4.0	4.0
Openness	5.0	1.5
Self-hosting	5.0	1.0
Multimodality	5.0	3.5

Scores come from live data — output price (cost), context length, open vs closed weights (openness & self-hosting) and vision/tool support (multimodality). Raw task quality isn't scored here; it depends on your benchmark — see the verdict.

What each model is

Mistral Medium 3.5 Open

Mistral AI · Open-weight

Mistral Medium 3.5 is a dense 128B instruction-following model from Mistral AI. It supports text and image inputs with text output, and is designed for agentic workflows, coding, and complex...

Aion 3.5 Paid

AionLabs · Proprietary

Aion 3.5 is a multi-model roleplaying and storytelling system from AionLabs, built on the GLM family of models. It uses a collaborative generation process in which multiple specialized models each...

Other models in these families

These variants are tracked but not compared here — one page per family keeps the comparison readable.

Other variants tracked

Mistral Large 4Mistral Medium 3.5 (batch)Mistral Small 4Mistral Small 4 (batch)Mistral Large 3 2512Mistral Large 3 2512 (batch)Mistral Medium 3.1Mistral Medium 3.1 (batch)Mistral Medium 3Devstral 2 2512Mistral Small 3.1 24BMistral Small 3.2 24BMistral LargeMistral Large 2407Mistral Small 3SabaMinistral 3 14B 2512Mixtral 8x22B InstructMinistral 3 8B 2512Ministral 3 8B 2512 (batch)Ministral 3 3B 2512UncensoredCodestral 2508Codestral 2508 (batch)Voxtral Small 24B 2507Mistral Nemo

Frequently asked questions

Is Mistral Medium 3.5 as good as Aion 3.5?

Mistral Medium 3.5 is open-weight and competitive on many tasks, but Aion 3.5 may still lead on the hardest reasoning and agentic work. The gap keeps narrowing — benchmark both on your actual use case before deciding.

Can I run Mistral Medium 3.5 locally?

Yes. Mistral Medium 3.5 has open weights, so you can self-host it on your own GPUs or run it via a low-cost API. Aion 3.5 is API-only and cannot be self-hosted.

Mistral Medium 3.5 vs Aion 3.5 — which should I pick in 2026?

Choose Mistral Medium 3.5 if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose Aion 3.5 if you want frontier capability through a managed API with zero infrastructure to run.

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