AI Models · Open-Source vs Paid

Phi 4 Open vs AIAion 3.5 Mini Paid

Phi 4 vs Aion 3.5 Mini compared — price per token, context window, multimodality, openness and which to choose. Can the open-source model replace the paid one? Full 2026 breakdown.

Prices & specs refreshed from live data · olud.ai

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

Phi 4OpenMicrosoft
$0.07 /M input
$0.14 /M outputNo per-token fees if you self-host
TypeOpen-weight
Context window16K tokens
MultimodalNo
Self-hostYes
AIAion 3.5 MiniPaidAionLabs
$0.7 /M input
$1.4 /M outputManaged API (no infra to run)
TypeProprietary
Context window262K tokens
MultimodalNo
Self-hostNo
Choose Phi 4 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 Mini if you want frontier capability through a managed API with zero infrastructure to run.

Phi 4 vs Aion 3.5 Mini specs

SpecPhi 4Aion 3.5 MiniWinner
MakerMicrosoftAionLabs–
TypeOpen-weightProprietaryPhi 4
Context window16K tokens262K tokensAIAion 3.5 Mini
Input price$0.07/M · free self-host$0.7/MPhi 4
Output price$0.14/M · free self-host$1.4/MPhi 4
Vision / multimodalNoNo–
Tool / function callingNoYesAIAion 3.5 Mini
Self-hostableYesNo (API only)Phi 4
LicenseMITProprietaryPhi 4

Price gap & when to choose each

10.0×cheaper per output token

Phi 4 is ~10.0× cheaper than Aion 3.5 Mini on output tokens ($0.14 vs $1.4 per M tokens).

Choose Phi 4 if…
  • You want to self-host or run on your cloud
  • You prioritize data privacy & control
  • You want the lowest operating costs
  • You are building open or reproducible AI
AIChoose Aion 3.5 Mini if…
  • You want frontier performance through a managed API
  • You need the longer 262K context window
  • You value reliability & ecosystem
  • You don't want to manage infrastructure

Feature comparison

CapabilityPhi 4Aion 3.5 Mini
Open weights (downloadable)✓✗
Self-hostable✓✗
Runs fully offline✓✗
Vision / multimodal✗✗
Tool / function calling✗✓
1M+ context window✗✗

Benchmarks: Phi 4 vs Aion 3.5 Mini

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

Phi 4
Aion 3.5 Mini
Intelligence index
5.9
–
Math index
18
–
GPQA
57.5%
–
MMLU-Pro
71.4%
–
Humanity's Last Exam
3.8%
–
Long Context Reasoning
0%
–
LiveCodeBench
23.1%
–
MATH-500
81%
–
AIME
14.3%
–
AIME 2025
18%
–
IFBench
23.5%
–
τ²-Bench
0%
–
Terminal-Bench Hard
3.8%
–
Speed
41.8 tok/s
–
Latency
1.07s
–
Intelligence per $
26.9
–

Benchmark data by Artificial Analysis.

How Phi 4 and Aion 3.5 Mini score

🏆 Best value & openness: Phi 4 (3.8 vs 2.9 / 5)
CriterionPhi 4Aion 3.5 Mini
Cost-efficiency5.04.5
Context window2.04.0
Openness5.01.5
Self-hosting5.01.0
Multimodality2.03.5

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

Phi 4 Open

Microsoft · Open-weight

[Microsoft Research](/microsoft) Phi-4 is designed to perform well in complex reasoning tasks and can operate efficiently in situations with limited memory or where quick responses are needed. At 14 billion...

Aion 3.5 Mini Paid

AionLabs · Proprietary

Aion 3.5 Mini is a multi-model roleplaying and storytelling system from AionLabs, built on the GLM family of models. It is the smaller, lower-cost sibling of Aion 3.5 and uses...

Frequently asked questions

Is Phi 4 as good as Aion 3.5 Mini?

Phi 4 is open-weight and competitive on many tasks, but Aion 3.5 Mini 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 Phi 4 locally?

Yes. Phi 4 has open weights, so you can self-host it on your own GPUs or run it via a low-cost API. Aion 3.5 Mini is API-only and cannot be self-hosted.

How much cheaper is Phi 4?

Phi 4 costs $0.14/M output vs $1.4/M for Aion 3.5 Mini — roughly 10x cheaper via API, and free if you self-host.

Phi 4 vs Aion 3.5 Mini — which should I pick in 2026?

Choose Phi 4 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 Mini if you want frontier capability through a managed API with zero infrastructure to run.

People also compare

Explore more open-source AI

Browse the full open-source model leaderboard, thousands of tools and live benchmarks — all in one place.

Open the leaderboard →