Comparison · OpenAI and Z.ai
GPT-5.4 vs GLM 5.3 Prime
Listed API prices of GPT-5.4 and GLM 5.3 Prime turned into the cost of the same three standard tasks and what each provider’s API documentation says about features that break on a switch. Output quality, speed and answer length are not compared.
Calculated impact cost per task and per month
For an L2 task (deep analysis over a 50,000-token document, 3 steps), GPT-5.4 costs $0.443 and GLM 5.3 Prime $0.472 at the prices listed in the United States on , so GPT-5.4 is 6.2 % less than GLM 5.3 Prime, counting visible output only, without cache discounts or hidden reasoning.
| Task | GPT-5.4, per task | GLM 5.3 Prime, per task | GPT-5.4, per month | GLM 5.3 Prime, per month | GPT-5.4 vs GLM 5.3 Prime, per task |
|---|---|---|---|---|---|
| L1Micro-task (classification or strict JSON extraction) | $0.0067per L1 task | $0.0060per L1 task | $98.55per month | $87.02per month | +13.3 % |
| L2Deep analysis over a 50,000-token document | $0.443per L2 task | $0.472per L2 task | $6,460.50per month | $6,885.36per month | −6.2 % |
| L3Agentic coding loop, 15 steps | $3.42per L3 task | $3.76per L3 task | $49,986.75per month | $54,933.96per month | −9.0 % |
Calculated Per month: 20 tasks an hour around the clock, 730 hours.
Prices USD per 1M tokens
| Price | GPT-5.4 | GLM 5.3 Prime |
|---|---|---|
| Input, per 1M tokens | $2.50 | $2.80 |
| Output, per 1M tokens | $15.00 | $8.80 |
| Price from | OpenRouter · source page (data) Published | OpenRouter · source page (data) Published |
| Read | · the United States | · the United States |
| Context window | 1,050,000 tokens | 1,000,000 tokens |
What breaks when you switch Published provider documentation
Moving from OpenAI to Z.ai, 4 of the 5 features may not carry over, by each provider’s documentation:
- Strict JSON schemas — OpenAI: yes; Z.ai: partly. Code that parses answers without checks starts failing where a provider promises only valid JSON, not your schema.
- Parallel tool calls — OpenAI: yes; Z.ai: not stated. An agent built around several calls per turn gets one call per turn: more round trips, more input tokens, slower runs.
- Streamed tool arguments — OpenAI: yes; Z.ai: partly. An interface that shows arguments as they are written sees nothing until the whole call is ready.
- Cache covers tool definitions — OpenAI: yes; Z.ai: not stated. Where the cache does not cover tool definitions, a long tool list is paid as fresh input on every request.
Moving from Z.ai to OpenAI: every feature that Z.ai’s documentation lists as supported is also listed as supported by OpenAI.
| Feature of the API | OpenAI | Z.ai |
|---|---|---|
| Strict JSON schemas | Yes | Partly |
| Parallel tool calls | Yes | Not stated |
| Streamed tool arguments | Yes | Partly |
| Reasoning with tools | Yes | Yes |
| Cache covers tool definitions | Yes | Not stated |
What each provider’s own API documentation says, read ; “not stated” is not the same as “no”. Quotes and sources: what breaks when you switch AI APIs.