# Z.ai vs StepFun

> Two Chinese open-weight labs with permissive licenses. Z.ai leads on coding tools and cheap text; StepFun leads on low-cost vision and video understanding.

Canonical: https://www.subconscious.dev/compare/z-ai-vs-stepfun · By The Subconscious Team · Updated September 30, 2026

## How they compare

Z.ai and StepFun share a lot. Both are Chinese labs, both ship permissive open weights, MIT for GLM and Apache 2.0 for key Step releases, and both serve first-party inference from China. They split on focus. Z.ai's pitch is coding, with GLM-5.3 at $1.40 in and $4.40 out, the GLM Coding Plan from $18 a month and an Anthropic-compatible endpoint for Claude Code. StepFun's pitch is efficient multimodal models. Step 3.7 Flash is a 198B vision-language model with 11B active parameters and 256K context, at $0.20 in and $1.15 out.

For text at the lowest cost, Z.ai has the edge, with GLM-5.3-Flash at $0.075 in and $0.25 out and older Flash models at zero. For images and video, StepFun's models are the ones built for it, and the lab also makes speech and audio models. Both carry the same caution for Western buyers. Z.ai's servers add 100 to 200ms from the US or Europe, and StepFun has thin Western distribution and support, though OpenRouter carries its models. StepFun trails frontier models on hard multimodal reasoning, while GLM-5 launched first among open-weight models on the Artificial Analysis index.

## What each one does

### Z.ai

Z.AI is the international brand of Chinese lab Zhipu AI, maker of the GLM models. Its current flagship, GLM-5.3, shipped August 17, 2026 at $1.40 in and $4.40 out per million tokens, with cached input at $0.26. GLM-5.3-Flash costs $0.075 in and $0.25 out, and several older Flash models are priced at zero, a real free tier instead of trial credits. GLM-5, released in February 2026, is a 744B mixture-of-experts model under an MIT license, and at launch it ranked first among open-weight models on the Artificial Analysis index with a record-low hallucination score.

### StepFun

StepFun is a Shanghai AI lab known for efficient multimodal models, with a mix of proprietary API models and open-weight releases. Its current workhorse, Step 3.7 Flash, came out in May 2026 as a 198B mixture-of-experts vision-language model with only 11B active parameters. It has 256K context, selectable reasoning levels, tool use and structured outputs, and it ships under Apache 2.0. StepFun's own API prices it at $0.20 in and $1.15 out per million tokens, and OpenRouter carries it too.

## Which is best, and when

### Choose Z.ai for

- Budget coding agents in Claude Code
- The cheapest text calls on GLM Flash
- The $18 GLM Coding Plan

### Choose StepFun for

- Vision and video understanding at low cost
- Self-hosting a small-active-parameter multimodal model
- Speech and audio alongside vision

## At a glance

| Attribute | Z.ai | StepFun |
|---|---|---|
| Model access | Open weights (MIT) | Open (Apache 2.0) and API models |
| Flagship models | GLM-5.3, GLM-5.3-Flash | Step 3.7 Flash, Step3 |
| Speed | ~80 tok/s on GLM-5.3 | ~128 tok/s on Step 3.7 Flash |
| Price | $1.40 in, $4.40 out (GLM-5.3); free Flash tier | $0.20 in, $1.15 out (Step 3.7 Flash) |
| Customization | Open weights, no license limits | Open weights to fine-tune |
| Deployment | API, GLM Coding Plan | First-party API, OpenRouter |
| Long context | 1M (GLM-5.3) | 256K |

## FAQ

### What is the difference between Z.ai and StepFun?

Two Chinese open-weight labs with permissive licenses. Z.ai leads on coding tools and cheap text; StepFun leads on low-cost vision and video understanding.

### When should I choose Z.ai over StepFun?

Budget coding agents in Claude Code; The cheapest text calls on GLM Flash; The $18 GLM Coding Plan.

### When should I choose StepFun over Z.ai?

Vision and video understanding at low cost; Self-hosting a small-active-parameter multimodal model; Speech and audio alongside vision.

### Is Z.ai or StepFun cheaper?

Z.ai: $1.40 in, $4.40 out (GLM-5.3); free Flash tier. StepFun: $0.20 in, $1.15 out (Step 3.7 Flash). The cheaper choice depends on the model and workload.

### Which has more context, Z.ai or StepFun?

Z.ai: 1M (GLM-5.3). StepFun: 256K.

## Running long-horizon agents?

If your agents run past 200K tokens, compare both against Subconscious: [Subconscious vs Z.ai](https://www.subconscious.dev/compare/subconscious-vs-z-ai.md), [Subconscious vs StepFun](https://www.subconscious.dev/compare/subconscious-vs-stepfun.md).

Full profiles: [Z.ai](https://www.subconscious.dev/providers/z-ai.md), [StepFun](https://www.subconscious.dev/providers/stepfun.md).