GLM 5.1 vs Mistral Medium 3

Z.ai · China  |  Mistral AI · France · Updated June 2026

Quick verdict

Pick GLM 5.1 for long-horizon autonomous agentic engineering (up to 8-hour runs) or state-of-the-art open-weight coding (topped swe-bench pro at launch). Pick Mistral Medium 3 for strong cost-to-capability at $0.40/$2.00 or general reasoning, coding and multimodal tasks. Choose GLM 5.1 if you need self-hosting or data privacy; Mistral Medium 3 if you want a managed API.

GLM 5.1 (Z.ai, China) and Mistral Medium 3 (Mistral AI, France) line up two different AI ecosystems against each other — a comparison that is as much about cost philosophy and openness as raw capability. GLM 5.1 is an open-weight (MIT) Chinese coding model built for long-horizon agentic engineering, topping SWE-Bench Pro at launch while running autonomously for up to 8 hours. Mistral Medium 3 is mistral's mid-tier model at $0.40/$2.00 — efficient general capability with a 128K window, below the 1M-context frontier tier. 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

SpecGLM 5.1Mistral Medium 3
ProviderZ.ai (China) Mistral AI (France)
ReleasedApril 7, 2026 May 7, 2025
Context window200K (~300 pages) 128K (~192 pages)
Price (in/out)$1.4/$4.4 per 1M tokens $0.4/$2 per 1M tokens
Open weight?Yes — self-hostable No — API only
Modalitiestext, code text, image, code
SWE-Bench VerifiedNot published Not published
MRCR v2 @ 1MNot published Not published

Who wins what

Long-horizon autonomous agentic engineering (up to 8-hour runs)

GLM 5.1

Its 200K window holds about 1.6× more than Mistral Medium 3's 128K in a single prompt.

State-of-the-art open-weight coding (topped SWE-Bench Pro at launch)

GLM 5.1

Open weights make this possible at all — Mistral Medium 3 is API-only, so it cannot leave the vendor's servers.

Sustained tool use across thousands of calls

GLM 5.1

An open-weight (MIT) Chinese coding model built for long-horizon agentic engineering, topping SWE-Bench Pro at launch while running autonomously for up to 8 hours — and it carries the larger 200K context.

Strong cost-to-capability at $0.40/$2.00

Mistral Medium 3

At $0.4/$2 per 1M tokens it undercuts GLM 5.1 ($1.4/$4.4 per 1M tokens), and that gap compounds at volume.

General reasoning, coding and multimodal tasks

Mistral Medium 3

Mistral's mid-tier model at $0.40/$2.00 — efficient general capability with a 128K window, below the 1M-context frontier tier — and it runs cheaper at $0.4/$2 per 1M tokens.

Efficient mid-tier deployment for production workloads

Mistral Medium 3

Mistral Medium 3 lists efficient mid-tier deployment for production workloads among its strengths; GLM 5.1 does not.

Lowest cost at scale

Mistral Medium 3

At $0.4/$2 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.

Largest single-prompt input

GLM 5.1

Its 200K window is about 1.6× larger than Mistral Medium 3's 128K, fitting roughly 300 pages in one prompt.

Which should you pick?

A cost-sensitive startup shipping high volume

Mistral Medium 3

At $0.4/$2 per 1M tokens it undercuts GLM 5.1, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

GLM 5.1

Larger 200K window fits more in one prompt.

A team with data-privacy or self-hosting needs

GLM 5.1

Open weights let you run it on your own hardware; Mistral Medium 3 is API-only.

Anyone whose priority is long-horizon autonomous agentic engineering (up to 8-hour runs)

GLM 5.1

It is specifically built for that.

Anyone whose priority is strong cost-to-capability at $0.40/$2.00

Mistral Medium 3

That is its strongest area.

An enterprise with regional data-residency rules

Mistral Medium 3 or GLM 5.1

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

GLM 5.1: where it fits

An open-weight (MIT) Chinese coding model built for long-horizon agentic engineering, topping SWE-Bench Pro at launch while running autonomously for up to 8 hours. Released April 7, 2026 by Z.ai, it is built for long-horizon autonomous agentic engineering (up to 8-hour runs), state-of-the-art open-weight coding (topped SWE-Bench Pro at launch), sustained tool use across thousands of calls, and self-hostable under a permissive MIT license.

Its trade-offs are real: text-only, with no image, audio, or video input, and 754B-parameter MoE demands heavy GPU resources to self-host. At $1.4 in / $4.4 out per million tokens, it sits in the mid price band.

Mistral Medium 3: where it fits

Mistral's mid-tier model at $0.40/$2.00 — efficient general capability with a 128K window, below the 1M-context frontier tier. Released May 7, 2025 by Mistral AI, it is built for strong cost-to-capability at $0.40/$2.00, general reasoning, coding and multimodal tasks, efficient mid-tier deployment for production workloads, and text and image input.

Its trade-offs: a 128K context — smaller than the 1M-window flagships here, no published SWE-Bench Verified score, a mid-tier model, not a frontier reasoner, and proprietary, unlike Mistral's open-weight releases. At $0.4 in / $2 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. GLM 5.1 gives you weights you control — self-host it, fine-tune it, keep data in-house, pay only for hardware. Mistral Medium 3 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 GLM 5.1 and Mistral Medium 3 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 GLM 5.1 or Mistral Medium 3 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, GLM 5.1 leans toward long-horizon autonomous agentic engineering (up to 8-hour runs) while Mistral Medium 3 leans toward strong cost-to-capability at $0.40/$2.00, and that positioning usually predicts which feels better on your codebase.

Which is cheaper, GLM 5.1 or Mistral Medium 3?

GLM 5.1 is open-weight, so self-hosting means no per-token fee (you pay for hardware instead), while Mistral Medium 3 is API-metered at $0.4/$2 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?

GLM 5.1 — 200K vs 128K, about 1.6× larger. Useful only if the model actually reasons over the full window, which not all do.

Can I use both GLM 5.1 and Mistral Medium 3 together?

Yes — a multi-model platform like LumiChats gives you GLM 5.1, Mistral Medium 3 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, GLM 5.1 or Mistral Medium 3?

GLM 5.1 — released April 7, 2026, about 11 months after Mistral Medium 3.

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.