GLM-5.3 vs Claude Sonnet 5
An open-weight coding model against a proprietary frontier Sonnet — weights, pricing, and ecosystem compared.
Updated August 28, 2026 · Independent comparison — GLM-5.3, Claude Sonnet 5 are separate products.
GLM-5.3
Z.ai's open-weight agentic coding model
Z.ai's GLM-5.3 is an open-weight coding, agentic, and cybersecurity model built on the GLM-5 base and improved through large-scale post-training. On Z.ai's own tests it reaches 28.3 on Terminal-Bench 3.0 (state-of-the-art among open-source models), 66.9 on DeepSWE v1.1, and 28.5 on Agents' Last Exam, and serves 128K output with always-on reasoning and function calling. It's priced at $1.40/$4.40 per million tokens ($0.26 cache read) through Z.ai's API — which speaks the OpenAI and Anthropic protocols — or the flat-rate GLM Coding Plan. Its 744B-total / 40B-active weights are scheduled to publish on Hugging Face on 2026-08-28, with the Flash variant already public; a raw context figure isn't published, though the Coding-Plan [1m] endpoint exposes a 1M-token window.
Claude Sonnet 5
Anthropic's most agentic Sonnet
Claude Sonnet 5 (model ID claude-sonnet-5) is Anthropic's proprietary frontier Sonnet, released June 30, 2026 and described as its most agentic Sonnet yet. It runs a 1M-token context with 128K output and native text and image input, pairing extended thinking with strong tool use, and Anthropic highlights its OSWorld-Verified computer-use results. Pricing is $2/$10 per million input/output tokens — an introductory rate that became permanent on August 10, 2026 — with cache reads at $0.20 and up to 90% savings via prompt caching. It's available through the Anthropic API, the Claude apps (Pro/Max/Team/Enterprise), Claude Code, Amazon Bedrock, and Google Vertex.
Bottom line
An open-weight coding model against a proprietary frontier Sonnet — weights, pricing, and ecosystem compared. Choose GLM-5.3 if you want open weights you can self-host (publishing 2026-08-28) instead of a closed API; choose Claude Sonnet 5 if you want a proven proprietary frontier model with Anthropic's extended-thinking tool use.
Model & Access
| Feature | GLM-5.3 | Claude Sonnet 5 |
|---|---|---|
| Developer | Z.ai (Zhipu) | Anthropic |
| Model ID | glm-5.3 | claude-sonnet-5 |
| Open weights | HF release scheduled 2026-08-28 (Flash already public) | ✗ |
| Parameters | 744B total / 40B active (MoE) | Not disclosed |
| Multimodal input | Not stated (text) | Text, image |
Context & Output
| Feature | GLM-5.3 | Claude Sonnet 5 |
|---|---|---|
| Context window | Not published (1M via Coding-Plan [1m] endpoint) | 1M tokens |
| Max output | 128K tokens | 128K tokens |
| Reasoning | Always on (low / high / max) | Extended thinking + agentic |
| Tool / function calling | ✓ | ✓ |
Pricing (per 1M tokens)
| Feature | GLM-5.3 | Claude Sonnet 5 |
|---|---|---|
| Input | $1.40 | $2.00 |
| Output | $4.40 | $10.00 |
| Cache read | $0.26 | $0.20 (up to 90% savings) |
| Subscription plan | GLM Coding Plan (Lite / Pro / Max) | Claude Pro / Max / Team / Enterprise |
Coding & Agentic Benchmarks
| Feature | GLM-5.3 | Claude Sonnet 5 |
|---|---|---|
| Terminal-Bench 3.0 | 28.3 (open-source SOTA) | Not published |
| DeepSWE v1.1 | 66.9 | Not published |
| Computer use | Not stated | OSWorld-Verified (highlighted by Anthropic) |
| Specific SWE-bench scores | Vendor benchmarks published | Not stated on model page |
| Positioning | Coding + cybersecurity | Most agentic Sonnet yet |
Ecosystem & Openness
| Feature | GLM-5.3 | Claude Sonnet 5 |
|---|---|---|
| Self-host | At/after 2026-08-28 release | ✗ |
| First-party agent | GLM Coding Plan / Claude Code endpoint | Claude Code, Claude apps |
| Clouds / APIs | Z.ai API (OpenAI + Anthropic protocols) | Anthropic API, Amazon Bedrock, Google Vertex |
| Released | August 2026 | June 30, 2026 |
The Verdict
Choose GLM-5.3 if...
- ✓You want open weights you can self-host (publishing 2026-08-28) instead of a closed API.
- ✓You want lower per-token pricing ($1.40/$4.40) or a flat-rate GLM Coding Plan.
- ✓You want published open-source SOTA on Terminal-Bench 3.0 for agentic coding.
- ✓You want a coding/cybersecurity-tuned model with native Anthropic-protocol endpoints.
- ✓Data residency or on-prem control matters more than top proprietary benchmark scores.
Choose Claude Sonnet 5 if...
- ✓You want a proven proprietary frontier model with Anthropic's extended-thinking tool use.
- ✓You need native image input and strong computer-use / agentic performance.
- ✓You want first-party Claude Code plus Amazon Bedrock and Google Vertex availability.
- ✓You value prompt caching (up to 90% savings) on large repeated contexts.
- ✓You'd rather have a managed, supported API than run open weights yourself.
Frequently Asked Questions
What is the difference between GLM-5.3 and Claude Sonnet 5?
Z.ai's GLM-5.3 is an open-weight coding, agentic, and cybersecurity model built on the GLM-5 base and improved through large-scale post-training. Claude Sonnet 5 (model ID claude-sonnet-5) is Anthropic's proprietary frontier Sonnet, released June 30, 2026 and described as its most agentic Sonnet yet.
How much do GLM-5.3 and Claude Sonnet 5 cost?
GLM-5.3: $1.40. Claude Sonnet 5: $2.00. See the pricing table above for full plan details.
Should I choose GLM-5.3 or Claude Sonnet 5?
Choose GLM-5.3 if you want open weights you can self-host (publishing 2026-08-28) instead of a closed API. Choose Claude Sonnet 5 if you want a proven proprietary frontier model with Anthropic's extended-thinking tool use.
1DevToolOpen weights or frontier API — run both
GLM-5.3 and Claude Sonnet 5 sit at opposite ends: an open-weight coding model you can self-host versus a managed frontier API. 1DevTool runs Claude Code (Sonnet 5) alongside Codex, Gemini CLI, Cline, and OpenCode in persistent terminals — drop in an Anthropic key or a GLM Coding Plan key, switch per task, and use the built-in HTTP client, 13-engine database client, and embedded browser. One-time $29, no subscription.