Coding · Head-to-head
OpenAI Codex vs GLM-5.3
OpenAI Codex vs GLM-5.3: pricing, features, and which to pick in 2026.
The verdict
Pick OpenAI Codex if…
- →your primary use case is teams already standardised on chatgpt who want the coding agent bundled with the seats they pay for, and who want the same agent in a terminal, an editor and a pull request.
- →you need: development, agents, productivity
Side-by-side specs
| Spec | OpenAI Codex | GLM-5.3 |
|---|---|---|
| Category | Coding | Coding |
| Pricing model | freemium | freemium |
| Headline pricing | Included with ChatGPT Free, Go, Plus, Pro, Business, Edu and Enterprise plans | Freemium via Z.ai GLM Coding Plan and ZCode (paid tiers for API access) |
| Free tier | Yes. OpenAI documents Codex as included on the ChatGPT Free plan, with access described as restricted to basic tasks. | Limited API access and hosted inference |
| AI Score | 8.8/10 | 8.5/10 |
| Best for | Teams already standardised on ChatGPT who want the coding agent bundled with the seats they pay for, and who want the same agent in a terminal, an editor and a pull request. | — |
| Editor's pick | — | ✓ Yes |
| Use cases | development agents productivity | — |
| Date added | 2026-08-02 | 2026-08-17 |
Pros and cons
🧑💻
OpenAI Codex
Coding · freemium
Pros
- ✓Included in ChatGPT plans from the free tier upward, so most organisations already own it
- ✓Covers the terminal, the editor, a hosted cloud runner, the ChatGPT apps and GitHub pull request review from one entitlement
- ✓AGENTS.md keeps agent configuration in the repo and under version control rather than in someone's local settings
- ✓Three GPT-5.6 variants let a team route cheap work to Luna and hard work to Sol instead of paying one rate for everything
- ✓Overflow credits are priced per million tokens, which makes the marginal cost of extra work legible
Cons
- ×Published limits are ranges per rolling five-hour window that span two orders of magnitude, so the included allowance is not knowable in advance
- ×Usage depends on which model variant a task routes to, and routing is not fully under the user's control
- ×Pro pricing is presented as tiers rather than a single figure, so the real cost of the heavy plan needs checking at the point of sale
- ×The agent is tied to a ChatGPT account, which is awkward for teams that standardised on a different assistant vendor
GLM-5.3
Coding · freemium
Pros
- ✓Open weights enable local and fine-tuned deployment
- ✓Documented 50% coding benchmark lift over GLM-5.2
- ✓Demonstrated real-world vulnerability discovery
- ✓Strong long-horizon task performance
Cons
- ×Requires self-hosting or paid API for full capability
- ×Newer model with limited third-party ecosystem
- ×Cybersecurity focus may introduce unintended behaviors in non-security tasks
Related comparisons
Updated 2026-08-17. Spec data sourced from official product pages and tracked in our public directory at /tools.