gpt-oss-120b vs Laguna XS 2.1

OpenAI · US  |  Poolside · US · Updated June 2026

Quick verdict

Pick gpt-oss-120b for self-hostable on a single 80gb h100 gpu via mxfp4 or configurable reasoning depth (low/medium/high). 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. On a tight budget at scale, gpt-oss-120b is the value pick.

gpt-oss-120b (OpenAI) and Laguna XS 2.1 (Poolside) are two of the models people most often weigh against each other in 2026. gpt-oss-120b is openAI's open-weight 117B-parameter MoE reasoning model (5.1B active) that runs on a single 80GB GPU and approaches o4-mini on reasoning, coding, and tool use. 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. They diverge most on price, context window and coding benchmarks — each quantified below from the models' real specs.

Key differences at a glance

Side-by-side specs

Specgpt-oss-120bLaguna XS 2.1
ProviderOpenAI (US) Poolside (US)
ReleasedAugust 5, 2025 July 2, 2026
Context window131K (~197 pages) 256K (~393 pages)
Price (in/out)Open weight (self-host / free) $0.1/$0.2 per 1M tokens
Open weight?Yes — self-hostable Yes — self-hostable
Modalitiestext, code text, code
SWE-Bench Verified62.4% 70.9%
MRCR v2 @ 1MNot published Not published

Who wins what

Self-hostable on a single 80GB H100 GPU via MXFP4

gpt-oss-120b

gpt-oss-120b lists self-hostable on a single 80GB H100 GPU via MXFP4 among its strengths; Laguna XS 2.1 does not.

Configurable reasoning depth (low/medium/high)

gpt-oss-120b

gpt-oss-120b lists configurable reasoning depth (low/medium/high) among its strengths; Laguna XS 2.1 does not.

Agentic tool use, function calling, and code execution

gpt-oss-120b

Laguna XS 2.1 is comparatively weak here — weak on harder agentic work (37.5 on Terminal-Bench 2.0), and its gain over XS.2 is barely above noise

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

Laguna XS 2.1

It scores 70.9% on SWE-Bench Verified against gpt-oss-120b's 62.4% — a 8.5-point edge on real repository work.

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

Laguna XS 2.1

A 33B open-weight coding MoE running on 3B active parameters — 70.9% SWE-Bench Verified and very cheap, but unproven — and it leads SWE-Bench Verified 70.9% to 62.4%.

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

Laguna XS 2.1

gpt-oss-120b is comparatively weak here — text-only, no image, audio, or video input

Lowest cost at scale

gpt-oss-120b

Its weights are open, so at volume you pay for your own hardware instead of Laguna XS 2.1's $0.1/$0.2 per 1M tokens.

Largest single-prompt input

Laguna XS 2.1

Its 256K window is about 2× larger than gpt-oss-120b's 131K, fitting roughly 393 pages in one prompt.

Which should you pick?

A cost-sensitive startup shipping high volume

gpt-oss-120b

At Open weight (self-host / free) it undercuts Laguna XS 2.1, 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.

Anyone whose priority is self-hostable on a single 80gb h100 gpu via mxfp4

gpt-oss-120b

It is specifically built for that.

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

Laguna XS 2.1

That is its strongest area.

gpt-oss-120b: where it fits

OpenAI's open-weight 117B-parameter MoE reasoning model (5.1B active) that runs on a single 80GB GPU and approaches o4-mini on reasoning, coding, and tool use. Released August 5, 2025 by OpenAI, it is built for self-hostable on a single 80GB H100 GPU via MXFP4, configurable reasoning depth (low/medium/high), agentic tool use, function calling, and code execution, and full chain-of-thought visibility for debugging.

Its trade-offs are real: text-only, no image, audio, or video input, and 131K context and 5.1B active params trail the largest frontier closed models. As an open-weight model, its running cost is your own hardware rather than a per-token fee.

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: 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.

The bottom line for this matchup

gpt-oss-120b and Laguna XS 2.1 overlap enough that the right pick depends on your specific job. gpt-oss-120b costs less per token; Laguna XS 2.1 holds the larger context; and each leads in its own area — gpt-oss-120b for self-hostable on a single 80gb h100 gpu via mxfp4, Laguna XS 2.1 for remarkable efficiency — 70.9% on swe-bench verified from only 3b active parameters. Rather than crowning one, run the same hard task through both once and let the results decide.

Want both gpt-oss-120b and Laguna XS 2.1 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-oss-120b or Laguna XS 2.1 better for coding?

On SWE-Bench Verified, gpt-oss-120b scores 62.4% and Laguna XS 2.1 scores 70.9% — Laguna XS 2.1 has the measurable edge.

Which is cheaper, gpt-oss-120b or Laguna XS 2.1?

gpt-oss-120b is cheaper — Open weight (self-host / free) vs $0.1/$0.2 per 1M tokens.

Which has the bigger context window?

Laguna XS 2.1 — 256K vs 131K, about 2× larger. Useful only if the model actually reasons over the full window, which not all do.

Can I use both gpt-oss-120b and Laguna XS 2.1 together?

Yes — a multi-model platform like LumiChats gives you gpt-oss-120b, Laguna XS 2.1 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-oss-120b or Laguna XS 2.1?

Laguna XS 2.1 — released July 2, 2026, about 11 months after gpt-oss-120b.

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.