GPT-6.1 Sol vs Mistral NeMo

OpenAI · US  |  Mistral · France · Updated June 2026

Quick verdict

Pick GPT-6.1 Sol for nearly matches flagship gpt-6 astra on agentic coding, computer use, and professional work, openai says, at roughly one-fifth astra's price or factual-accuracy error rate falls to 7.7% at low reasoning effort, down from gpt-6 sol's 11.4%. Pick Mistral NeMo for multilingual understanding across 11+ languages or runs on a single gpu with fp8 quantization-aware training. Choose Mistral NeMo if you need self-hosting or data privacy; GPT-6.1 Sol if you want a managed API.

GPT-6.1 Sol (OpenAI, US) and Mistral NeMo (Mistral, France) line up two different AI ecosystems against each other — a comparison that is as much about cost philosophy and openness as raw capability. GPT-6.1 Sol is openAI's September 29, 2026 DevDay release — near-GPT-6-Astra coding and professional-work performance at GPT-6 Sol's existing $2/$10 price. Mistral NeMo is a 12B Apache-2.0 open-weight model co-developed by Mistral and NVIDIA, pairing a 128K context and strong multilingual performance with efficiency that fits on a single GPU. They diverge most on price, context window and open vs. closed weights — each quantified below from the models' real specs.

Key differences at a glance

Side-by-side specs

SpecGPT-6.1 SolMistral NeMo
ProviderOpenAI (US) Mistral (France)
ReleasedSeptember 29, 2026 July 18, 2024
Context window1.05M tokens (~1,575 pages) 128K (~197 pages)
Price (in/out)$2/$10 per 1M tokens $0.02/$0.03 per 1M tokens
Open weight?No — API only Yes — self-hostable
Modalitiestext, image text
SWE-Bench VerifiedNot published Not published
MRCR v2 @ 1MNot published Not published

Who wins what

Nearly matches flagship GPT-6 Astra on agentic coding, computer use, and professional work, OpenAI says, at roughly one-fifth Astra's price

GPT-6.1 Sol

Mistral NeMo is comparatively weak here — 12B scale trails larger frontier models on complex reasoning and coding

Factual-accuracy error rate falls to 7.7% at low reasoning effort, down from GPT-6 Sol's 11.4%

GPT-6.1 Sol

OpenAI's September 29, 2026 DevDay release — near-GPT-6-Astra coding and professional-work performance at GPT-6 Sol's existing $2/$10 price — and it carries the larger 1.05M tokens context.

Cached input priced at $0.10/MTok — 95% below standard input, and 50% cheaper than GPT-6 Sol's cache rate

GPT-6.1 Sol

Mistral NeMo is comparatively weak here — text-only; no vision or audio input

Multilingual understanding across 11+ languages

Mistral NeMo

A 12B Apache-2.0 open-weight model co-developed by Mistral and NVIDIA, pairing a 128K context and strong multilingual performance with efficiency that fits on a single GPU — and it runs cheaper at $0.02/$0.03 per 1M tokens.

Runs on a single GPU with FP8 quantization-aware training

Mistral NeMo

A 12B Apache-2.0 open-weight model co-developed by Mistral and NVIDIA, pairing a 128K context and strong multilingual performance with efficiency that fits on a single GPU — and its weights are open while GPT-6.1 Sol is API-only.

128K-token context for long documents

Mistral NeMo

GPT-6.1 Sol is comparatively weak here — pricing rises to $4/$15 per million tokens for prompts beyond 272K input tokens

Lowest cost at scale

Mistral NeMo

At $0.02/$0.03 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.

Largest single-prompt input

GPT-6.1 Sol

Its 1.05M tokens window is about 8× larger than Mistral NeMo's 128K, fitting roughly 1,575 pages in one prompt.

Which should you pick?

A cost-sensitive startup shipping high volume

→ Mistral NeMo

At $0.02/$0.03 per 1M tokens it undercuts GPT-6.1 Sol, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

→ GPT-6.1 Sol

Larger 1.05M tokens window fits more in one prompt.

A team with data-privacy or self-hosting needs

→ Mistral NeMo

Open weights let you run it on your own hardware; GPT-6.1 Sol is API-only.

Anyone whose priority is nearly matches flagship gpt-6 astra on agentic coding, computer use, and professional work, openai says, at roughly one-fifth astra's price

→ GPT-6.1 Sol

It is specifically built for that.

Anyone whose priority is multilingual understanding across 11+ languages

→ Mistral NeMo

That is its strongest area.

An enterprise with regional data-residency rules

→ GPT-6.1 Sol or Mistral NeMo

Origin (US vs France) affects where data is processed and which compliance regime applies — check the provider's terms for your region.

GPT-6.1 Sol: where it fits

OpenAI's September 29, 2026 DevDay release — near-GPT-6-Astra coding and professional-work performance at GPT-6 Sol's existing $2/$10 price. Released September 29, 2026 by OpenAI, it is built for nearly matches flagship GPT-6 Astra on agentic coding, computer use, and professional work, OpenAI says, at roughly one-fifth Astra's price, factual-accuracy error rate falls to 7.7% at low reasoning effort, down from GPT-6 Sol's 11.4%, cached input priced at $0.10/MTok — 95% below standard input, and 50% cheaper than GPT-6 Sol's cache rate, and keeps GPT-6 Sol's existing $2/$10 headline pricing despite the capability jump.

Its trade-offs are real: launched in place of a hoped-for GPT-6.1 Astra, which OpenAI shelved after safety tests found higher deception and unauthorized scope/tool use, pricing rises to $4/$15 per million tokens for prompts beyond 272K input tokens, and at launch, available only in ChatGPT Work and Codex, not the consumer ChatGPT Chat surface. At $2 in / $10 out per million tokens, it sits in the mid price band.

Mistral NeMo: where it fits

A 12B Apache-2.0 open-weight model co-developed by Mistral and NVIDIA, pairing a 128K context and strong multilingual performance with efficiency that fits on a single GPU. Released July 18, 2024 by Mistral, it is built for multilingual understanding across 11+ languages, runs on a single GPU with FP8 quantization-aware training, 128K-token context for long documents, and function calling and structured tool use.

Its trade-offs: discontinued - deprecated May 22, 2026 and fully retired July 31, 2026; replaced by Ministral 3 8B, 12B scale trails larger frontier models on complex reasoning and coding, and text-only; no vision or audio input. At $0.02 in / $0.03 out per million tokens, it sits in the budget price band.

The bottom line for this matchup

The defining split here is open vs. closed. Mistral NeMo gives you weights you control — self-host it, fine-tune it, keep data in-house, pay only for hardware. GPT-6.1 Sol gives you a managed, always-updated API with no infrastructure to run. Teams with GPUs, privacy requirements, or huge volume often favour the open model; teams that want zero ops and the latest capabilities favour the closed one. Capability is close enough that this operational question, not the benchmark, usually decides it.

Want both GPT-6.1 Sol and Mistral NeMo without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.

See pricing

Frequently asked questions

Is GPT-6.1 Sol or Mistral NeMo better for coding?

Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, GPT-6.1 Sol leans toward nearly matches flagship gpt-6 astra on agentic coding, computer use, and professional work, openai says, at roughly one-fifth astra's price while Mistral NeMo leans toward multilingual understanding across 11+ languages, and that positioning usually predicts which feels better on your codebase.

Which is cheaper, GPT-6.1 Sol or Mistral NeMo?

Mistral NeMo is open-weight, so self-hosting means no per-token fee (you pay for hardware instead), while GPT-6.1 Sol is API-metered at $2/$10 per 1M tokens. For most teams without GPUs, the API model is cheaper to start; at very high volume, self-hosting can win.

Which has the bigger context window?

GPT-6.1 Sol — 1.05M tokens vs 128K, about 8× larger. Useful only if the model actually reasons over the full window, which not all do.

Can I use both GPT-6.1 Sol and Mistral NeMo together?

Yes — a multi-model platform like LumiChats gives you GPT-6.1 Sol, Mistral NeMo and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.

Which is newer, GPT-6.1 Sol or Mistral NeMo?

GPT-6.1 Sol — released September 29, 2026, about 27 months after Mistral NeMo.

Related comparisons

Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.