AI Models · Open-Source vs Paid

GPT-6.1 Terra Pro Paid vs Mistral Medium 3.5 (batch) Open

GPT-6.1 Terra Pro vs Mistral Medium 3.5 (batch) 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.

GPT-6.1 Terra ProPaidOpenAI
$1 /M input
$5 /M outputManaged API (no infra to run)
TypeProprietary
Context window1.1M tokens
MultimodalYes
Self-hostNo
Mistral Medium 3.5 (batch)OpenMistral AI
$0.75 /M input
$3.75 /M outputNo per-token fees if you self-host
TypeOpen-weight
Context window262K tokens
MultimodalYes
Self-hostYes
Choose Mistral Medium 3.5 (batch) 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 GPT-6.1 Terra Pro if you want frontier capability through a managed API with zero infrastructure to run.

GPT-6.1 Terra Pro vs Mistral Medium 3.5 (batch) specs

SpecGPT-6.1 Terra ProMistral Medium 3.5 (batch)Winner
MakerOpenAIMistral AI–
TypeProprietaryOpen-weightMistral Medium 3.5 (batch)
Context window1.1M tokens262K tokensGPT-6.1 Terra Pro
Input price$1/M$0.75/M · free self-hostMistral Medium 3.5 (batch)
Output price$5/M$3.75/M · free self-hostMistral Medium 3.5 (batch)
Vision / multimodalYesYes= Tie
Tool / function callingYesYes= Tie
Self-hostableNo (API only)YesMistral Medium 3.5 (batch)
LicenseProprietaryApache 2.0Mistral Medium 3.5 (batch)

Price gap & when to choose each

Choose GPT-6.1 Terra Pro if…
  • You want frontier performance through a managed API
  • You need the longer 1.1M context window
  • You value reliability & ecosystem
  • You don't want to manage infrastructure
Choose Mistral Medium 3.5 (batch) 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

Feature comparison

CapabilityGPT-6.1 Terra ProMistral Medium 3.5 (batch)
Open weights (downloadable)✗✓
Self-hostable✗✓
Runs fully offline✗✓
Vision / multimodal✓✓
Tool / function calling✓✓
1M+ context window✓✗

Benchmarks: GPT-6.1 Terra Pro vs Mistral Medium 3.5 (batch)

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

GPT-6.1 Terra Pro
Mistral Medium 3.5 (batch)
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
–
174.8 tok/s
Latency
–
0.61s
Intelligence per $
–
4.7

Benchmark data by Artificial Analysis.

How GPT-6.1 Terra Pro and Mistral Medium 3.5 (batch) score

🏆 Best value & openness: Mistral Medium 3.5 (batch) (4.6 vs 3.3 / 5)
CriterionGPT-6.1 Terra ProMistral Medium 3.5 (batch)
Cost-efficiency4.04.0
Context window5.04.0
Openness1.55.0
Self-hosting1.05.0
Multimodality5.05.0

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

GPT-6.1 Terra Pro Paid

OpenAI · Proprietary

GPT-6.1 Terra Pro is the same underlying model as [GPT-6.1 Terra](https://openrouter.ai/openai/gpt-6.1-terra), served with `reasoning.mode` set to `pro` for higher-quality responses on complex tasks. **Cost note:** pro mode spends far more.

Mistral Medium 3.5 (batch) 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...

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 3.5Mistral Small 4Mistral Large 3 2512Mistral Medium 3.1Mistral 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 3B 2512UncensoredCodestral 2508Voxtral Small 24B 2507Mistral Nemo

Frequently asked questions

Is Mistral Medium 3.5 (batch) as good as GPT-6.1 Terra Pro?

Mistral Medium 3.5 (batch) is open-weight and competitive on many tasks, but GPT-6.1 Terra Pro 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 (batch) locally?

Yes. Mistral Medium 3.5 (batch) has open weights, so you can self-host it on your own GPUs or run it via a low-cost API. GPT-6.1 Terra Pro is API-only and cannot be self-hosted.

GPT-6.1 Terra Pro vs Mistral Medium 3.5 (batch) — which should I pick in 2026?

Choose Mistral Medium 3.5 (batch) 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 GPT-6.1 Terra Pro if you want frontier capability through a managed API with zero infrastructure to run.

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