GLM-5.3 vs Muse Spark Open vs Claude Sonnet 5.5
Claude Sonnet 5.5 comes out ahead, 72 to 68 and 63 on our weighted score, though Muse Spark Open is 2× cheaper per token.
Z.ai (Zhipu)GLM-5.3
63/100- ECI156.2
- Price$1.40 / $4.40
- Context1M
MetaMuse Spark Open
68/100- ECI155.1
- Price$1.25 / $4.25
- Context1.05M
- Our pick
AnthropicClaude Sonnet 5.5
72/100- ECI166.7
- Price$2.00 / $10.00
- Context1M
Claude Sonnet 5.5 is our pick
Claude Sonnet 5.5 is the better all-round choice, scoring 72/100 against Muse Spark Open (68) and GLM-5.3 (63). It leads on capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityClaude Sonnet 5.5Capabilities Index (ECI): Claude Sonnet 5.5 166.7 · GLM-5.3 156.2 · Muse Spark Open 155.1
- Lowest priceMuse Spark OpenMuse Spark Open $2.00 · GLM-5.3 $2.15 · Claude Sonnet 5.5 $4.00 per 1M tokens (3:1 blend)
- Longest contextMuse Spark OpenMuse Spark Open 1,048,576 · GLM-5.3 1,000,000 · Claude Sonnet 5.5 1,000,000 tokens
- Widest inputsMuse Spark OpenGLM-5.3: Text · Muse Spark Open: Text, Images, Audio, Video · Claude Sonnet 5.5: Text, Images, PDFs
- Self-hostingGLM-5.3 and Muse Spark OpenPublishes downloadable weights (Muse Model License)
| Measure | Weight | GLM-5.3 | Muse Spark Open | Claude Sonnet 5.5 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 84 | 83 | 97 |
| Price | 25% | 33 | 34 | 20 |
| Inputs & features | 15% | 45 | 80 | 80 |
| Context window | 10% | 60 | 61 | 60 |
| Overall | 100% | 63/100 | 68/100 | 72/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GLM-5.3Z.ai (Zhipu) | Muse Spark OpenMeta | Claude Sonnet 5.5Anthropic |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 156.2 | 155.1 | 166.7 (best) |
| ECI rank | #33 of 165 | #39 of 165 | #5 of 165 (best) |
| GPQA DiamondGraduate-level science questions | 90.9% | 88.6% | 95.6% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | 68.8% | 69.8% | 88.8% (best) |
| OTIS Mock AIME 2024–2025Competition mathematics | 91.1% | 98.1% | 100% (best) |
| SimpleQA VerifiedShort factual questions | 41.0% | 56.6% (best) | 46.5% |
| Price per million tokens | |||
| Input | $1.40 | $1.25 (best) | $2.00 |
| Output | $4.40 | $4.25 (best) | $10.00 |
| Cached input | $0.26 | — | $0.10 (best) |
| Blended (3:1) | $2.15 | $2.00 (best) | $4.00 |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Z.AI API | Median of 16 providers | Official Anthropic API |
| Limits | |||
| Context window | 1,000,000 tokens | 1,048,576 tokens (best) | 1,000,000 tokens |
| Max output | 131,072 tokens (best) | 131,072 tokens (best) | 128,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | No | Yes | Yes |
| PDFs | No | No | Yes |
| Audio | No | Yes | No |
| Video | No | Yes | No |
| Reasoning | Yeslow · high · max | Yes | Yeslow · medium · high · xhigh · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | No | Yes |
| Availability | |||
| Weights | Open | OpenMuse Model License | Proprietary |
| API model ID | glm-5.3 | — | claude-sonnet-5-5 |
| API providers | 83 (best) | 16 | 34 |
| Released | Aug 14, 2026 | Oct 15, 2026 | Sep 28, 2026 |
| Knowledge cutoff | — | Jan 4, 2026 | Jun 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- GLM-5.3$22.80
- Muse Spark Open$21.00
- Claude Sonnet 5.5$40.00
Which should you choose?
Which is better: GLM-5.3, Muse Spark Open or Claude Sonnet 5.5?
Claude Sonnet 5.5 is the better all-round choice, scoring 72/100 against Muse Spark Open (68) and GLM-5.3 (63). It leads on capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GLM-5.3, Muse Spark Open or Claude Sonnet 5.5?
Muse Spark Open is cheaper at $1.25 input / $4.25 output per million tokens (median across 16 API providers). GLM-5.3 costs $1.40 input / $4.40 output per million tokens (official Z.AI API price); Claude Sonnet 5.5 costs $2.00 input / $10.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $2.00 per million tokens for Muse Spark Open versus $2.15 for GLM-5.3 (1.1× as much) and $4.00 for Claude Sonnet 5.5 (2× as much).
Which scores higher on benchmarks?
Claude Sonnet 5.5 scores higher on the Capabilities Index (ECI): Claude Sonnet 5.5 166.7 (#5 of 165), GLM-5.3 156.2 (#33 of 165) and Muse Spark Open 155.1 (#39 of 165). Their confidence ranges do not overlap (163.6–171.3 vs 154.3–158.5), so the gap is a real one. On individual benchmarks: GPQA Diamond — Claude Sonnet 5.5 95.6%, GLM-5.3 90.9%, Muse Spark Open 88.6%; FrontierMath Tiers 1–3 — Claude Sonnet 5.5 88.8%, Muse Spark Open 69.8%, GLM-5.3 68.8%; OTIS Mock AIME 2024–2025 — Claude Sonnet 5.5 100%, Muse Spark Open 98.1%, GLM-5.3 91.1%; SimpleQA Verified — Muse Spark Open 56.6%, Claude Sonnet 5.5 46.5%, GLM-5.3 41.0%.
Which is better for coding?
There are no published SWE-bench Verified results for GLM-5.3, Muse Spark Open and Claude Sonnet 5.5 yet, so there is no like-for-like coding score. On overall capability, Claude Sonnet 5.5 leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.
Which has the bigger context window?
Muse Spark Open has the largest context window at 1,048,576 tokens, against 1,000,000 for GLM-5.3 and 1,000,000 for Claude Sonnet 5.5. Maximum output per response: GLM-5.3 up to 131,072, Muse Spark Open up to 131,072, Claude Sonnet 5.5 up to 128,000 tokens.
Which can read images, PDFs, audio or video?
GLM-5.3 accepts text; Muse Spark Open accepts text, images, audio and video; Claude Sonnet 5.5 accepts text, images and PDFs. Muse Spark Open handles the widest range of inputs.
Are any of these open source?
GLM-5.3 and Muse Spark Open publishes its weights (Muse Model License) and can be self-hosted; Claude Sonnet 5.5 is proprietary.
Which is newer?
Muse Spark Open is the newest, released Oct 15, 2026. Claude Sonnet 5.5 came out Sep 28, 2026; GLM-5.3 came out Aug 14, 2026. Knowledge cutoff: Muse Spark Open Jan 4, 2026, Claude Sonnet 5.5 Jun 2026.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.
