GLM 5 vs GPT-4o mini

Z.ai · China  |  OpenAI · US · Updated June 2026

Quick verdict

Pick GLM 5 for agentic planning and long-horizon coding workflows or complex systems design and backend reasoning. Pick GPT-4o mini for very low cost per token for its capability tier or strong coding for a small model (87.2% humaneval). Choose GLM 5 if you need self-hosting or data privacy; GPT-4o mini if you want a managed API.

GLM 5 (Z.ai, China) and GPT-4o mini (OpenAI, US) 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 is z.ai's flagship open-weight (MIT) MoE foundation model, engineered for complex systems design and long-horizon agentic coding. GPT-4o mini is openAI's budget small multimodal model — cheap, fast text-and-vision intelligence that outscored peer small models like Gemini 1.5 Flash and Claude 3 Haiku on MMLU and HumanEval at launch. 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 5GPT-4o mini
ProviderZ.ai (China) OpenAI (US)
ReleasedFebruary 11, 2026 July 18, 2024
Context window200K (~300 pages) 128K (~192 pages)
Price (in/out)$1/$3.2 per 1M tokens $0.15/$0.6 per 1M tokens
Open weight?Yes — self-hostable No — API only
Modalitiestext, code text, image
SWE-Bench Verified77.8% Not published
MRCR v2 @ 1MNot published Not published

Who wins what

Agentic planning and long-horizon coding workflows

GLM 5

A core design strength of GLM 5.

Complex systems design and backend reasoning

GLM 5

A core design strength of GLM 5.

Iterative self-correction on autonomous tasks

GLM 5

A core design strength of GLM 5.

Very low cost per token for its capability tier

GPT-4o mini

A core design strength of GPT-4o mini.

Strong coding for a small model (87.2% HumanEval)

GPT-4o mini

A core design strength of GPT-4o mini.

Leading MMLU among peer small models (82%)

GPT-4o mini

A core design strength of GPT-4o mini.

Lowest cost at scale

GPT-4o mini

At $0.15/$0.6 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

Its 200K window is about 1.6× larger, fitting roughly 300 pages in one prompt.

Which should you pick?

A cost-sensitive startup shipping high volume

GPT-4o mini

At $0.15/$0.6 per 1M tokens it undercuts GLM 5, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

GLM 5

Larger 200K window fits more in one prompt.

A team with data-privacy or self-hosting needs

GLM 5

Open weights let you run it on your own hardware; GPT-4o mini is API-only.

Anyone whose priority is agentic planning and long-horizon coding workflows

GLM 5

It is specifically built for that.

Anyone whose priority is very low cost per token for its capability tier

GPT-4o mini

That is its strongest area.

An enterprise with regional data-residency rules

GPT-4o mini or GLM 5

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

GLM 5: where it fits

Z.ai's flagship open-weight (MIT) MoE foundation model, engineered for complex systems design and long-horizon agentic coding. Released February 11, 2026 by Z.ai, it is built for agentic planning and long-horizon coding workflows, complex systems design and backend reasoning, iterative self-correction on autonomous tasks, and open weights under the permissive MIT license.

Its trade-offs are real: 200K context trails 1M-context rivals, and quickly superseded by GLM-5.1 and GLM-5.2. At $1 in / $3.2 out per million tokens, it sits in the budget price band.

GPT-4o mini: where it fits

OpenAI's budget small multimodal model — cheap, fast text-and-vision intelligence that outscored peer small models like Gemini 1.5 Flash and Claude 3 Haiku on MMLU and HumanEval at launch. Released July 18, 2024 by OpenAI, it is built for very low cost per token for its capability tier, strong coding for a small model (87.2% HumanEval), leading MMLU among peer small models (82%), and text and image (vision) understanding in the API.

Its trade-offs: only 128K context with an October 2023 knowledge cutoff, and weaker on hard reasoning and coding than frontier models. At $0.15 in / $0.6 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 gives you weights you control — self-host it, fine-tune it, keep data in-house, pay only for hardware. GPT-4o 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 GLM 5 and GPT-4o mini 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 or GPT-4o mini better for coding?

Public SWE-Bench figures are not available for GPT-4o mini, so the honest test is your own repository — run an identical real bug through both. By design, GLM 5 leans toward agentic planning and long-horizon coding workflows while GPT-4o mini leans toward very low cost per token for its capability tier, and that positioning usually predicts which feels better on your codebase.

Which is cheaper, GLM 5 or GPT-4o mini?

GLM 5 is open-weight, so self-hosting means no per-token fee (you pay for hardware instead), while GPT-4o mini is API-metered at $0.15/$0.6 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 — 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 and GPT-4o mini together?

Yes — a multi-model platform like LumiChats gives you GLM 5, GPT-4o mini 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 or GPT-4o mini?

GLM 5 — released February 11, 2026, about 19 months after GPT-4o 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.