GPT-5.4 Mini vs Laguna XS 2.1

OpenAI · US  |  Poolside · US · Updated June 2026

Quick verdict

Pick GPT-5.4 Mini for free for every chatgpt user or fast, low-cost general tasks. 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. Choose Laguna XS 2.1 if you need self-hosting or data privacy; GPT-5.4 Mini if you want a managed API.

GPT-5.4 Mini (OpenAI) and Laguna XS 2.1 (Poolside) are two of the models people most often weigh against each other in 2026. GPT-5.4 Mini is openAI's free, fast workhorse — capable general AI with no subscription needed. 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 open vs. closed weights — each quantified below from the models' real specs.

Key differences at a glance

Side-by-side specs

SpecGPT-5.4 MiniLaguna XS 2.1
ProviderOpenAI (US) Poolside (US)
ReleasedMarch 17, 2026 July 2, 2026
Context window400K (~600 pages) 256K (~393 pages)
Price (in/out)$0.75/$4.5 per 1M tokens $0.1/$0.2 per 1M tokens
Open weight?No — API only Yes — self-hostable
Modalitiestext, image, code text, code
SWE-Bench VerifiedNot published 70.9%
MRCR v2 @ 1MNot published Not published

Who wins what

Free for every ChatGPT user

GPT-5.4 Mini

Laguna XS 2.1 is comparatively weak here — weeks old with no independent replication; every published score traces back to Poolside's own harness

Fast, low-cost general tasks

GPT-5.4 Mini

OpenAI's free, fast workhorse — capable general AI with no subscription needed — and it carries the larger 400K context.

Subagent capabilities

GPT-5.4 Mini

GPT-5.4 Mini lists subagent capabilities among its strengths; Laguna XS 2.1 does not.

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

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 runs cheaper at $0.1/$0.2 per 1M tokens.

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 — GPT-5.4 Mini 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 GPT-5.4 Mini ($0.75/$4.5 per 1M tokens), and that gap compounds at volume.

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

GPT-5.4 Mini

Its 400K window is about 1.5× larger than Laguna XS 2.1's 256K, fitting roughly 600 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 GPT-5.4 Mini, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

GPT-5.4 Mini

Larger 400K 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; GPT-5.4 Mini is API-only.

Anyone whose priority is free for every chatgpt user

GPT-5.4 Mini

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-5.4 Mini: where it fits

OpenAI's free, fast workhorse — capable general AI with no subscription needed. Released March 17, 2026 by OpenAI, it is built for free for every ChatGPT user, fast, low-cost general tasks, subagent capabilities, and native multimodal reasoning.

Its trade-offs are real: smaller context than flagship models, and not for the hardest reasoning. At $0.75 in / $4.5 out per million tokens, it sits in the budget price band.

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

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. GPT-5.4 Mini 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-5.4 Mini 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-5.4 Mini or Laguna XS 2.1 better for coding?

Public SWE-Bench figures are not available for GPT-5.4 Mini, so the honest test is your own repository — run an identical real bug through both. By design, GPT-5.4 Mini leans toward free for every chatgpt user while Laguna XS 2.1 leans toward remarkable efficiency — 70.9% on swe-bench verified from only 3b active parameters, and that positioning usually predicts which feels better on your codebase.

Which is cheaper, GPT-5.4 Mini or Laguna XS 2.1?

Laguna XS 2.1 is open-weight, so self-hosting means no per-token fee (you pay for hardware instead), while GPT-5.4 Mini is API-metered at $0.75/$4.5 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-5.4 Mini — 400K vs 256K, about 1.5× larger. Useful only if the model actually reasons over the full window, which not all do.

Can I use both GPT-5.4 Mini and Laguna XS 2.1 together?

Yes — a multi-model platform like LumiChats gives you GPT-5.4 Mini, 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-5.4 Mini or Laguna XS 2.1?

Laguna XS 2.1 — released July 2, 2026, about 4 months after GPT-5.4 Mini.

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.