GLM-5.3-Flash vs Step 3.5 Flash
GLM-5.3-Flash comes out ahead, 79 to 62 on our weighted score, though Step 3.5 Flash is 37% cheaper per token.
- Our pick
Z.ai (Zhipu)GLM-5.3-Flash
79/100- ECI151.9
- Price$0.15 / $0.50
- Context1M
StepFunStep 3.5 Flash
62/100- ECI—
- Price$0.10 / $0.30
- Context256K
Add a model
Make it a three-way comparison.
GLM-5.3-Flash is our pick
GLM-5.3-Flash is the better all-round choice, scoring 79/100 against Step 3.5 Flash (62). It leads on inputs & features and context window. Step 3.5 Flash wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
- CapabilityNot enough dataNo independent benchmark covers every model here yet
- Lowest priceStep 3.5 FlashStep 3.5 Flash $0.15 · GLM-5.3-Flash $0.237 per 1M tokens (3:1 blend)
- Longest contextGLM-5.3-FlashGLM-5.3-Flash 1,000,000 · Step 3.5 Flash 256,000 tokens
- Widest inputsGLM-5.3-FlashGLM-5.3-Flash: Text, Images, PDFs, Video · Step 3.5 Flash: Text
- Self-hostingAll open weightsEvery model here can be downloaded and run on your own hardware
| Measure | Weight | GLM-5.3-Flash | Step 3.5 Flash |
|---|---|---|---|
| Price | 50% | 79 | 89 |
| Inputs & features | 30% | 90 | 35 |
| Context window | 20% | 60 | 36 |
| Overall | 100% | 79/100 | 62/100 |
Left out because at least one model lacks the data: capability. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GLM-5.3-FlashZ.ai (Zhipu) | Step 3.5 FlashStepFun |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | 151.9 | — |
| ECI rank | #42 of 148 | — |
| GPQA DiamondGraduate-level science questions | 90.2% | — |
| FrontierMath Tiers 1–3Research-level mathematics | 55.8% | — |
| OTIS Mock AIME 2024–2025Competition mathematics | 93.9% | — |
| Price per million tokens | ||
| Input | $0.15 | $0.10 (best) |
| Output | $0.50 | $0.30 (best) |
| Cached input | $0.03 | $0.02 (best) |
| Blended (3:1) | $0.237 | $0.15 (best) |
| Long-context rate | Same rate | Same rate |
| Price source | Official Z.AI API | Official StepFun (Global) API |
| Limits | ||
| Context window | 1,000,000 tokens (best) | 256,000 tokens |
| Max output | 131,072 tokens | 256,000 tokens (best) |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | No |
| PDFs | Yes | No |
| Audio | No | No |
| Video | Yes | No |
| Reasoning | Yeslow · high · max | Yeslow · high |
| Tool calling | Yes | Yes |
| Structured output | Yes | No |
| Availability | ||
| Weights | Open | Open |
| API model ID | glm-5.3-flash | step-3.5-flash |
| API providers | 65 (best) | 8 |
| Released | Aug 26, 2026 | Jan 29, 2026 |
| Knowledge cutoff | — | Jan 2025 |
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-Flash$2.50
- Step 3.5 Flash$1.60
Which should you choose?
Which is better: GLM-5.3-Flash or Step 3.5 Flash?
GLM-5.3-Flash is the better all-round choice, scoring 79/100 against Step 3.5 Flash (62). It leads on inputs & features and context window. Step 3.5 Flash wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
Which is cheaper, GLM-5.3-Flash or Step 3.5 Flash?
Step 3.5 Flash is cheaper at $0.10 input / $0.30 output per million tokens (official StepFun (Global) API price). GLM-5.3-Flash costs $0.15 input / $0.50 output per million tokens (official Z.AI API price). At a typical mix of three input tokens to one output token, that is $0.15 per million tokens for Step 3.5 Flash versus $0.237 for GLM-5.3-Flash (1.6× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. GLM-5.3-Flash has an ECI of 151.9 and Step 3.5 Flash has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for GLM-5.3-Flash and Step 3.5 Flash yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.
Which has the bigger context window?
GLM-5.3-Flash has the largest context window at 1,000,000 tokens, against 256,000 for Step 3.5 Flash. Maximum output per response: GLM-5.3-Flash up to 131,072, Step 3.5 Flash up to 256,000 tokens.
Which can read images, PDFs, audio or video?
GLM-5.3-Flash accepts text, images, PDFs and video; Step 3.5 Flash accepts text. GLM-5.3-Flash handles the widest range of inputs.
Are any of these open source?
Yes, both publish their weights, so you can self-host them.
Which is newer?
GLM-5.3-Flash is the newest, released Aug 26, 2026. Step 3.5 Flash came out Jan 29, 2026. Knowledge cutoff: Step 3.5 Flash Jan 2025.
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 Oct 4, 2026.
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