Laguna XS 2.1 vs Mistral Medium 3

Poolside · US  |  Mistral AI · France · Updated June 2026

Quick verdict

Pick Laguna XS 2.1 for remarkable efficiency — 70.9% on swe-bench verified from only 3b active parameters or open weights under openmdw-1.1, shipped day one in bf16, fp8, nvfp4 and int4 across every major runtime. Pick Mistral Medium 3 for strong cost-to-capability at $0.40/$2.00 or general reasoning, coding and multimodal tasks. Choose Laguna XS 2.1 if you need self-hosting or data privacy; Mistral Medium 3 if you want a managed API.

Laguna XS 2.1 (Poolside, US) 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. Laguna XS 2.1 is a 33B open-weight coding MoE running on 3B active parameters — 70.9% SWE-Bench Verified and very cheap, but unproven. 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

SpecLaguna XS 2.1Mistral Medium 3
ProviderPoolside (US) Mistral AI (France)
ReleasedJuly 2, 2026 May 7, 2025
Context window256K (~393 pages) 128K (~192 pages)
Price (in/out)$0.1/$0.2 per 1M tokens $0.4/$2 per 1M tokens
Open weight?Yes — self-hostable No — API only
Modalitiestext, code text, image, code
SWE-Bench Verified70.9% Not published
MRCR v2 @ 1MNot published Not published

Who wins what

Remarkable efficiency — 70.9% on SWE-Bench Verified from only 3B active parameters

Laguna XS 2.1

Mistral Medium 3 is comparatively weak here — no published SWE-Bench Verified score

Open weights under OpenMDW-1.1, shipped day one in BF16, FP8, NVFP4 and INT4 across every major runtime

Laguna XS 2.1

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

Cheap even on the paid tier, at roughly a sixth of GLM 4.7's input price

Laguna XS 2.1

At $0.1/$0.2 per 1M tokens it undercuts Mistral Medium 3 ($0.4/$2 per 1M tokens), and that gap compounds at volume.

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

Mistral Medium 3

Mistral Medium 3 lists strong cost-to-capability at $0.40/$2.00 among its strengths; Laguna XS 2.1 does not.

General reasoning, coding and multimodal tasks

Mistral Medium 3

Mistral Medium 3 lists general reasoning, coding and multimodal tasks among its strengths; Laguna XS 2.1 does not.

Efficient mid-tier deployment for production workloads

Mistral Medium 3

Mistral Medium 3 lists efficient mid-tier deployment for production workloads among its strengths; Laguna XS 2.1 does not.

Lowest cost at scale

Laguna XS 2.1

At $0.1/$0.2 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.

Largest single-prompt input

Laguna XS 2.1

Its 256K window is about 2× larger than Mistral Medium 3's 128K, fitting roughly 393 pages in one prompt.

Which should you pick?

A cost-sensitive startup shipping high volume

Laguna XS 2.1

At $0.1/$0.2 per 1M tokens it undercuts Mistral Medium 3, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

Laguna XS 2.1

Larger 256K window fits more in one prompt.

A team with data-privacy or self-hosting needs

Laguna XS 2.1

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

Anyone whose priority is remarkable efficiency — 70.9% on swe-bench verified from only 3b active parameters

Laguna XS 2.1

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

Laguna XS 2.1 or Mistral Medium 3

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

Laguna XS 2.1: where it fits

A 33B open-weight coding MoE running on 3B active parameters — 70.9% SWE-Bench Verified and very cheap, but unproven. Released July 2, 2026 by Poolside, it is built for remarkable efficiency — 70.9% on SWE-Bench Verified from only 3B active parameters, open weights under OpenMDW-1.1, shipped day one in BF16, FP8, NVFP4 and INT4 across every major runtime, cheap even on the paid tier, at roughly a sixth of GLM 4.7's input price, and unusually transparent evaluation — it publishes its harness, step limits, and sandbox specs.

Its trade-offs are real: weeks old with no independent replication; every published score traces back to Poolside's own harness, the free endpoint trains on your inputs and outputs — disqualifying for proprietary code, which is its main use case, and weak on harder agentic work (37.5 on Terminal-Bench 2.0), and its gain over XS.2 is barely above noise. At $0.1 in / $0.2 out per million tokens, it sits in the budget 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. Laguna XS 2.1 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 Laguna XS 2.1 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 Laguna XS 2.1 or Mistral Medium 3 better for coding?

Public SWE-Bench figures are not available for Mistral Medium 3, so the honest test is your own repository — run an identical real bug through both. By design, Laguna XS 2.1 leans toward remarkable efficiency — 70.9% on swe-bench verified from only 3b active parameters 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, Laguna XS 2.1 or Mistral Medium 3?

Laguna XS 2.1 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?

Laguna XS 2.1 — 256K vs 128K, about 2× larger. Useful only if the model actually reasons over the full window, which not all do.

Can I use both Laguna XS 2.1 and Mistral Medium 3 together?

Yes — a multi-model platform like LumiChats gives you Laguna XS 2.1, 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, Laguna XS 2.1 or Mistral Medium 3?

Laguna XS 2.1 — released July 2, 2026, about 14 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.