Coding · Head-to-head
OpenAI Codex vs GLM-5.2
OpenAI Codex (freemium, AI Score 8.8/10) vs GLM-5.2 (freemium, AI Score 8.5/10). Side-by-side pricing, features, pros and cons, and which to pick.
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: productivity
Pick GLM-5.2 if…
- →your primary use case is engineering teams building coding agents who need frontier-class capability under a license they fully control — self-hosted, fine-tuned, or air-gapped — rather than rented from a closed api.
Side-by-side specs
| Spec | OpenAI Codex | GLM-5.2 |
|---|---|---|
| Category | Coding | Coding |
| Pricing model | freemium | freemium |
| Headline pricing | Included with ChatGPT Free, Go, Plus, Pro, Business, Edu and Enterprise plans | Free chat + MIT open weights; paid API and GLM Coding Plan — check site for current rates |
| Free tier | Yes. OpenAI documents Codex as included on the ChatGPT Free plan, with access described as restricted to basic tasks. | Yes — free chat access plus MIT-licensed weights you can download and run at no license cost. Hosted API and Coding Plan rates are not stated here because they were not verified against z.ai on the date of this update; check the site directly before budgeting. |
| 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. | Engineering teams building coding agents who need frontier-class capability under a license they fully control — self-hosted, fine-tuned, or air-gapped — rather than rented from a closed API. |
| Editor's pick | — | — |
| Use cases | development agents productivity | development agents |
| Date added | 2026-08-02 | 2026-06-27 |
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-5.2
Coding · freemium
Pros
- ✓MIT license at 744B parameters — commercial use, fine-tuning and redistribution with no revocable API terms or MAU clause
- ✓1M-token context handles whole repositories and long agent histories in one pass
- ✓Tuned for long-horizon, multi-turn tool use rather than one-shot completion, which is the workload coding agents actually run
- ✓Self-hosting is a genuine option for teams with data-residency or air-gap requirements, not a theoretical one
- ✓Materially cheaper than closed frontier tiers like GPT-5.6 Sol at $5/$30 per million tokens
Cons
- ×744B parameters means serious multi-GPU hardware to self-host, so most teams end up on the hosted API anyway — back on someone else's terms
- ×The launch claim of beating GPT-5.5 on long-horizon coding was vendor- and press-reported and still has no independent replication; GPT-5.6 Sol shipped in July and moved the comparison point
- ×The cheap-frontier field caught up fast — Qwen 3.8 Max at $2/$6 and Kimi K3 at $3/$15 offer comparable context, so GLM-5.2's cost edge is no longer distinctive
- ×Hosted API and Coding Plan prices are not published in an easily comparable form, and some enterprises face data-residency or procurement blocks on a China-based provider
Related comparisons
Updated 2026-08-10. Spec data sourced from official product pages and tracked in our public directory at /tools.