GPT-5.3-Codex vs Mistral Small 3.2 24B

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

Quick verdict

Pick GPT-5.3-Codex for dedicated coding agent or cli and ide integration. Pick Mistral Small 3.2 24B for extremely cheap open-weight model at about $0.075/$0.20 hosted or self-hostable under apache-2.0 with no per-token cost. Choose Mistral Small 3.2 24B if you need self-hosting or data privacy; GPT-5.3-Codex if you want a managed API.

GPT-5.3-Codex (OpenAI, US) and Mistral Small 3.2 24B (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. GPT-5.3-Codex is openAI's coding-specialized agent model for autonomous software engineering. Mistral Small 3.2 24B is mistral's Apache-2.0 open 24B model at about $0.075/$0.20 hosted — very cheap and self-hostable, sized for volume over frontier quality. 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-5.3-CodexMistral Small 3.2 24B
ProviderOpenAI (US) Mistral AI (France)
ReleasedFebruary 24, 2026 June 20, 2025
Context window400K (~600 pages) 256K (~384 pages)
Price (in/out)$1.75/$14 per 1M tokens $0.075/$0.2 per 1M tokens
Open weight?No — API only Yes — self-hostable
Modalitiestext, code text, image, code
SWE-Bench VerifiedNot published Not published
MRCR v2 @ 1MNot published Not published

Who wins what

Dedicated coding agent

GPT-5.3-Codex

OpenAI's coding-specialized agent model for autonomous software engineering — and it carries the larger 400K context.

CLI and IDE integration

GPT-5.3-Codex

OpenAI's coding-specialized agent model for autonomous software engineering — and it is the newer of the two.

Autonomous software tasks

GPT-5.3-Codex

GPT-5.3-Codex lists autonomous software tasks among its strengths; Mistral Small 3.2 24B does not.

Extremely cheap open-weight model at about $0.075/$0.20 hosted

Mistral Small 3.2 24B

At $0.075/$0.2 per 1M tokens it undercuts GPT-5.3-Codex ($1.75/$14 per 1M tokens), and that gap compounds at volume.

Self-hostable under Apache-2.0 with no per-token cost

Mistral Small 3.2 24B

Open weights make this possible at all — GPT-5.3-Codex is API-only, so it cannot leave the vendor's servers.

Instruction following and function calling at 24B scale

Mistral Small 3.2 24B

Mistral's Apache-2.0 open 24B model at about $0.075/$0.20 hosted — very cheap and self-hostable, sized for volume over frontier quality — and it runs cheaper at $0.075/$0.2 per 1M tokens.

Lowest cost at scale

Mistral Small 3.2 24B

At $0.075/$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-5.3-Codex

Its 400K window is about 1.6× larger than Mistral Small 3.2 24B's 256K, fitting roughly 600 pages in one prompt.

Which should you pick?

A cost-sensitive startup shipping high volume

Mistral Small 3.2 24B

At $0.075/$0.2 per 1M tokens it undercuts GPT-5.3-Codex, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

GPT-5.3-Codex

Larger 400K window fits more in one prompt.

A team with data-privacy or self-hosting needs

Mistral Small 3.2 24B

Open weights let you run it on your own hardware; GPT-5.3-Codex is API-only.

Anyone whose priority is dedicated coding agent

GPT-5.3-Codex

It is specifically built for that.

Anyone whose priority is extremely cheap open-weight model at about $0.075/$0.20 hosted

Mistral Small 3.2 24B

That is its strongest area.

An enterprise with regional data-residency rules

GPT-5.3-Codex or Mistral Small 3.2 24B

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

GPT-5.3-Codex: where it fits

OpenAI's coding-specialized agent model for autonomous software engineering. Released February 24, 2026 by OpenAI, it is built for dedicated coding agent, cLI and IDE integration, autonomous software tasks, and tool calling.

Its trade-offs are real: coding-specialized, narrower general use, and retired in favor of GPT-5.5 Codex. At $1.75 in / $14 out per million tokens, it sits in the mid price band.

Mistral Small 3.2 24B: where it fits

Mistral's Apache-2.0 open 24B model at about $0.075/$0.20 hosted — very cheap and self-hostable, sized for volume over frontier quality. Released June 20, 2025 by Mistral AI, it is built for extremely cheap open-weight model at about $0.075/$0.20 hosted, self-hostable under Apache-2.0 with no per-token cost, instruction following and function calling at 24B scale, and runs on modest hardware for local or private deployment.

Its trade-offs: a 24B small model — not a frontier reasoner, context reported as 256K but some references cite 128K native, no published SWE-Bench Verified score, and hosted prices vary by provider; the figure shown is a common host rate. At $0.075 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. Mistral Small 3.2 24B gives you weights you control — self-host it, fine-tune it, keep data in-house, pay only for hardware. GPT-5.3-Codex 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-5.3-Codex and Mistral Small 3.2 24B 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-5.3-Codex or Mistral Small 3.2 24B 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-5.3-Codex leans toward dedicated coding agent while Mistral Small 3.2 24B leans toward extremely cheap open-weight model at about $0.075/$0.20 hosted, and that positioning usually predicts which feels better on your codebase.

Which is cheaper, GPT-5.3-Codex or Mistral Small 3.2 24B?

Mistral Small 3.2 24B is open-weight, so self-hosting means no per-token fee (you pay for hardware instead), while GPT-5.3-Codex is API-metered at $1.75/$14 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-5.3-Codex — 400K vs 256K, about 1.6× larger. Useful only if the model actually reasons over the full window, which not all do.

Can I use both GPT-5.3-Codex and Mistral Small 3.2 24B together?

Yes — a multi-model platform like LumiChats gives you GPT-5.3-Codex, Mistral Small 3.2 24B 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-5.3-Codex or Mistral Small 3.2 24B?

GPT-5.3-Codex — released February 24, 2026, about 8 months after Mistral Small 3.2 24B.

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.