GLM-5.3 is Z.ai's flagship coding and agentic model, announced on August 14, 2026. It keeps the same mixture-of-experts base as GLM-5.2, the 744 billion parameter design with about 40 billion active per token, and every gain over its predecessor comes from a scaled-up post-training run rather than a new base. The model is text-only, supports a 1M-token context window with up to 128,000 tokens of output, and exposes a reasoning_effort parameter with low, high, and max levels that sets the thinking budget. Z.ai reports a 50% gain over GLM-5.2 on its in-house Code Bench, 28.3 on Terminal-Bench 3.0 against 4.6 for GLM-5.2, 66.9 on DeepSWE v1.1, and 88.2 on Terminal-Bench 2.1, and bills it as the most capable open-weights model for coding. The other headline is cybersecurity: vulnerability discovery was added to post-training and the capability grew faster than Z.ai expected, with a CyberGym score of 84.5, and the company says its models have turned up 2,436 vulnerabilities across 269 open-source projects since GLM-5.2. The weights were held back for a roughly two-week safety review before publication on Hugging Face, and unlike GLM-5.2 they ship under Z.ai's own GLM-5.3 license rather than MIT. It suits coding agents, long-horizon terminal work, and code review or vulnerability triage where the effort ladder lets you match reasoning depth to the task.
Call GLM-5.3 on Opper with the OpenAI SDK. Sign up without a credit card. Get started
GLM-5.3 runs on 22 different routes through the Opper gateway. Compare residency, zero data retention and training posture at a glance, with full data-handling detail per route below. In the EU it is served by evroc (Sweden), GreenPT, Inceptron and 5 more. See every GLM model hosted in the EU. Some routes also sell flex and priority processing: the same model at another price, picked per request with service_tier. How service tiers work.
GLM-5.3 runs on 6 independently monitored routes through the Opper gateway. A direct integration leaves you on one of them, the gateway serves whichever is healthy.
100%effective uptime, last 30 days
Averaged across these routes on their own, a single provider reached 96.43% over the same window.
Daily status through the gateway, which serves each request from whichever route is healthy.
6 monitored providers serve GLM-5.3.
Measured over the last 30 days from each provider's official status feed via StatusGator. Refreshed hourly. 15 further routes for this model are not on the board yet and are not counted above. See uptime for every provider Opper monitors.
Data handling per route
Each route hosting GLM-5.3 has its own privacy posture, residency, and GDPR terms. Postures are maintained by Opper with a last-verification timestamp.
Zero data retention with abuse monitoring: prompts and outputs are kept for abuse monitoring only, for a window the provider does not state, and are not used for training. No training on customer data. US; SCCs; DPA available.
Zero data retention with abuse monitoring: nothing is logged or used for training; content flagged by abuse monitoring is held for review. No training on customer data. US; dpf sccs; DPA available.
Zero data retention
With abuse monitoring, flagged content held.
Training
No training on customer data.
Logging
None
Abuse monitoring
Always on, holds flagged content, stored in United States
Zero data retention: nothing is logged, held for abuse monitoring or used for training. No training by default; opt-in possible. GLOBAL; SCCs; DPA available.
Zero data retention
Yes. Nothing is logged, held for abuse monitoring or used for training.
Zero data retention with abuse monitoring: prompts and outputs are kept for up to 30 days for abuse monitoring only, and are not used for training. No training on customer data. US; SCCs; DPA available.
Zero data retention
With abuse monitoring, 30-day window.
Training
No training on customer data.
Logging
Abuse monitoring (30-day retention)
Abuse monitoring
On by default, holds flagged content, a person can view samples
Zero data retention with abuse monitoring: nothing is logged or used for training; content flagged by abuse monitoring is held for review. No training on customer data. GLOBAL; unknown; DPA available.
Zero data retention
With abuse monitoring, flagged content held.
Training
No training on customer data.
Logging
None
Abuse monitoring
On by default, holds flagged content
Caching
Content cached for replay
Subprocessor access
Subprocessors may read content
GDPR DPA
DPA available
Transfer mechanism
unknown
Benchmarks
Independent benchmark scores — composite indices for reasoning, coding, and math, plus individual eval scores where available.
Call GLM-5.3 through the Opper gateway with one API key. Opper is drop-in compatible with the OpenAI, Anthropic and Google AI SDKs.
GLM-5.3 is a premium model on Opper. Sign up needs no credit card: you get an API key straight away and the free models work in the playground and the API. Add a card to use premium models, pay-as-you-go with no minimum.
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