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OpenAI vs Z.ai
OpenAI's premium closed tiers against Z.ai's MIT-licensed GLM models and $18 coding plan. Z.ai is far cheaper; OpenAI is closer to Western users and easier to buy.
By The Subconscious Team · Updated
OpenAI vs Z.ai: key differences
Z.ai competes on price at every tier. GLM-5.3 costs $1.40 in and $4.40 out, GLM-5.3-Flash costs $0.075 in and $0.25 out, and several older Flash models are free. Even OpenAI's cheapest tier, Luna at $0.20 in and $1.20 out, costs more than GLM-5.3-Flash. Z.ai's GLM Coding Plan starts at $18 a month on the Lite tier, a quota Z.ai says equals 15 to 30x the fee at API rates. It offers OpenAI-compatible endpoints, so swapping GLM in behind existing OpenAI client code is mostly configuration, and the weights are MIT-licensed with no license limits.
The trade-offs are location and predictability. Most of Z.ai's servers are in China, which costs 100 to 200ms per call from the US or Europe and worries enterprise data teams. Coding Plan quota also burns 2 to 3x faster on premium models during Beijing peak hours. OpenAI runs direct, through Azure OpenAI and through Bedrock, and GPT-6 Astra posts frontier results on computer use and coding benchmarks. Hosted tools and the Agents SDK have no match in Z.ai's listing. For solo developers and budget coding, Z.ai is the value pick. For enterprise products, OpenAI is.
What OpenAI and Z.ai do
OpenAI
OpenAI runs the most widely adopted closed-model API. Its September 2026 lineup has GPT-6 Astra at the top for computer use, coding and long agentic runs, priced at $10 in and $50 out per million tokens. Below it sits the GPT-5.6 family: Sol for hard professional work, Terra as the balanced default, and Luna for high-volume jobs at $0.20 in and $1.20 out. All of them carry a 1.05M token context window with up to 128K output.
Example models: GPT-6 Astra, GPT-5.6 Terra
Full OpenAI profileZ.ai
Z.AI is the international brand of Chinese lab Zhipu AI, maker of the GLM models. Its current flagship, GLM-5.3, shipped August 17, 2026 at $1.40 in and $4.40 out per million tokens, with cached input at $0.26. GLM-5.3-Flash costs $0.075 in and $0.25 out, and several older Flash models are priced at zero, a real free tier instead of trial credits. GLM-5, released in February 2026, is a 744B mixture-of-experts model under an MIT license, and at launch it ranked first among open-weight models on the Artificial Analysis index with a record-low hallucination score.
Example models: GLM-5.3, GLM-5.3-Flash
Full Z.ai profileShould you choose OpenAI or Z.ai?
OpenAI
Choose OpenAI for
- Enterprises with data or latency concerns about China-hosted servers
- Frontier computer use and browser automation
- Agents built on hosted tools and tracing
Z.ai
Choose Z.ai for
- Budget agentic coding on a flat monthly plan
- Near-free experiments on free GLM Flash models
- Self-hosting or fine-tuning MIT-licensed GLM weights
OpenAI vs Z.ai at a glance
| Attribute | OpenAI | Z.ai |
|---|---|---|
| Model access | Closed, plus open gpt-oss | Open weights (MIT) |
| Flagship models | GPT-6 Astra, GPT-5.6 Sol, Terra, Luna | GLM-5.3, GLM-5.3-Flash |
| Speed | Fast mode: up to 2.5x at 2x price | ~80 tok/s on GLM-5.3 |
| Price | $0.20–$10 in, $1.20–$50 out per 1M | $1.40 in, $4.40 out (GLM-5.3); free Flash tier |
| Customization | N/A | Open weights, no license limits |
| Deployment | API, Azure OpenAI, Bedrock | API, GLM Coding Plan |
| Long context | 1.05M; 2x input past 272K | 1M (GLM-5.3) |
Frequently asked questions
What is the difference between OpenAI and Z.ai?
OpenAI's premium closed tiers against Z.ai's MIT-licensed GLM models and $18 coding plan. Z.ai is far cheaper; OpenAI is closer to Western users and easier to buy.
When should I choose OpenAI over Z.ai?
Enterprises with data or latency concerns about China-hosted servers; Frontier computer use and browser automation; Agents built on hosted tools and tracing.
When should I choose Z.ai over OpenAI?
Budget agentic coding on a flat monthly plan; Near-free experiments on free GLM Flash models; Self-hosting or fine-tuning MIT-licensed GLM weights.
Is OpenAI or Z.ai cheaper?
OpenAI: $0.20–$10 in, $1.20–$50 out per 1M. Z.ai: $1.40 in, $4.40 out (GLM-5.3); free Flash tier. The cheaper choice depends on the model and workload.
Which has more context, OpenAI or Z.ai?
OpenAI: 1.05M; 2x input past 272K. Z.ai: 1M (GLM-5.3).
Related comparisons
Running long-horizon agents?
If your agents run past 200K tokens, compare both against Subconscious. Our inference stack treats a long-horizon trace as the primary workload, so speed, cost, and accuracy hold up deep into the trace.