ZMIME
Comparison · 2 models · Updated Oct 4, 2026

Step 3.5 Flash vs GLM-5.3-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.

  1. StepFun

    Step 3.5 Flash

    Released Jan 29, 2026

    62/100
    • ECI—
    • Price$0.10 / $0.30
    • Context256K
    Full specs Remove Step 3.5 Flash
  2. Our pick

    Z.ai (Zhipu)

    GLM-5.3-Flash

    Released Aug 26, 2026

    79/100
    • ECI151.9
    • Price$0.15 / $0.50
    • Context1M
    Full specs Remove GLM-5.3-Flash

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

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-FlashStep 3.5 Flash: Text · GLM-5.3-Flash: Text, Images, PDFs, Video
  • Self-hostingAll open weightsEvery model here can be downloaded and run on your own hardware
How the score is built
MeasureWeightStep 3.5 FlashGLM-5.3-Flash
Price50%8979
Inputs & features30%3590
Context window20%3660
Overall100%62/10079/100

Left out because at least one model lacks the data: capability. The remaining weights were rescaled.

02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

Step 3.5 Flash vs GLM-5.3-Flash specifications side by side
SpecificationStep 3.5 FlashStepFunGLM-5.3-FlashZ.ai (Zhipu)
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$0.10 (best)$0.15
Output$0.30 (best)$0.50
Cached input$0.02 (best)$0.03
Blended (3:1)$0.15 (best)$0.237
Long-context rateSame rateSame rate
Price sourceOfficial StepFun (Global) APIOfficial Z.AI API
Limits
Context window256,000 tokens1,000,000 tokens (best)
Max output256,000 tokens (best)131,072 tokens
Inputs and features
TextYesYes
ImagesNoYes
PDFsNoYes
AudioNoNo
VideoNoYes
ReasoningYeslow · highYeslow · high · max
Tool callingYesYes
Structured outputNoYes
Availability
WeightsOpenOpen
API model IDstep-3.5-flashglm-5.3-flash
API providers865 (best)
ReleasedJan 29, 2026Aug 26, 2026
Knowledge cutoffJan 2025—
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • Step 3.5 Flash$1.60
  • GLM-5.3-Flash$2.50
04 — Questions

Which should you choose?

Which is better: Step 3.5 Flash or GLM-5.3-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, Step 3.5 Flash or GLM-5.3-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. Step 3.5 Flash has not been scored yet and GLM-5.3-Flash has an ECI of 151.9.

Which is better for coding?

There are no published SWE-bench Verified results for Step 3.5 Flash and GLM-5.3-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: Step 3.5 Flash up to 256,000, GLM-5.3-Flash up to 131,072 tokens.

Which can read images, PDFs, audio or video?

Step 3.5 Flash accepts text; GLM-5.3-Flash accepts text, images, PDFs and video. 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.

05 — Keep comparing

Related comparisons