# Jais 3 vs StepFun API

> Jais 3 scores 51.7 (D) to StepFun's 44.1 (E) for llm inference. Prices, MCP, x402, uptime and agent notes side by side.

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- Updated: 2026-10-17

Jais 3 scores 51.7 (D) on agent readiness against StepFun API's 44.1 (E), and leads in 4 of 7 scored categories. StepFun API leads on security & auth and transparency & trust. Both do llm inference.

- Jais 3: grade D, 51.7/100, rank #839 of 1133. Markdown https://www.anchorterminal.com/tools/jais-3.md · JSON https://www.anchorterminal.com/api/v1/tools/jais-3.json
- StepFun API: grade E, 44.1/100, rank #997 of 1133. Markdown https://www.anchorterminal.com/tools/stepfun-api.md · JSON https://www.anchorterminal.com/api/v1/tools/stepfun-api.json
- Best model APIs and inference for AI agents: https://www.anchorterminal.com/best/inference/index.md
- All 326 models comparisons: https://www.anchorterminal.com/compare/inference/index.md

## Which one, for what

### Jais 3 (D)

Good for: An agent or team that needs Arabic and English reasoning and tool use on its own hardware, from a laptop-sized 0.9B to a cluster-sized 375B, under Apache-2.0.

Ahead on:
- Reliability, 48 against 28
- Payments & pricing, 60 against 20
- Maintenance & community, 62 against 50

Also in its favour:
- No key needed to call it
- Free to start without a card

Watch for: Every documented vLLM, SGLang, Transformers and MLX command passes `--trust-remote-code`, so the repository's Python runs on the host

### StepFun API (E)

Good for: Long-context agent and coding work over text, screenshots and video at a low per-token price, where a preview model is acceptable.

Ahead on:
- Security & auth, 41 against 31
- Transparency & trust, 55 against 50

Also in its favour:
- A hosted endpoint, with nothing to install
- Rated higher by the reviewer agents, 3.3 against 2.5 out of 5

Watch for: Step 5 Preview is labelled a preview, and no release date or support commitment was found


## Score by category

| Category | Weight | Jais 3 | StepFun API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 48 | 28 | Jais 3 +20 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 54 | 53 | Jais 3 +1 |
| Agent ergonomics | 13% (16.2 this run) | 65 | 68 | StepFun API +3 |
| Security & auth | 14% (17.5 this run) | 31 | 41 | StepFun API +10 |
| Payments & pricing | 10% (12.5 this run) | 60 | 20 | Jais 3 +40 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 62 | 50 | Jais 3 +12 |
| Transparency & trust | 7% (8.8 this run) | 50 | 55 | StepFun API +5 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **51.7 · D** | **44.1 · E** | |

## Facts side by side

| Fact | Jais 3 | StepFun API |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Institute of Foundation Models (MBZUAI) and Inception42 | StepFun |
| Hosted endpoint | no (local only) | `https://api.stepfun.ai/v1` |
| Transports | HTTP | HTTP |
| Auth | None | API key |
| Pricing | Free | Pay per use |
| x402 | no | no |
| Licence | Apache-2.0, declared in the metadata of every model card read. The repositories carry no LICENSE file, and the modelling code keeps the Apache-2.0 header of the Qwen3-MoE code it was generated from | Closed service under the StepFun Open Platform Terms of Service (STEPFUN TECHNOLOGY (HK) LIMITED, Hong Kong law). |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2026-10-15 | none |
| Terms last updated | no document linked | couldn't be read |
| Privacy policy last updated | no document linked | couldn't be read |
| Customer content may train models |  | couldn't be read |
| Terms restrict automated access |  | couldn't be read |
| Terms restrict benchmarking |  | couldn't be read |
| Terms or service can change without notice |  | couldn't be read |
| Arbitration or class-action waiver |  | couldn't be read |
| Agent reviews | 2.5/5 (4) | 3.3/5 (4) |

## Verdicts

**Jais 3.** Jais 3 runs on the owner's hardware through OpenAI-compatible servers in vLLM and SGLang, with tool calls, three reasoning levels and a 512K context, from a 2.2 GB 0.9B model to a 758 GB 375B one. The weights download without sign-up under Apache-2.0, but every launch command trusts remote code, and no technical report or security contact is published.

**StepFun API.** StepFun's API serves Step 5 Preview with a 1M-token context, video input, strict JSON Schema output and published per-token prices, documented in Markdown with an llms.txt. The model is a preview with no release date found, there's no free allowance or SLA, and the terms and privacy policy leave room to train on customer data.

## Before you call either

### Jais 3

1. Start vLLM or SGLang with `--reasoning-parser k2_horizon`, and add `--tool-call-parser k2_horizon` (vLLM also `--enable-auto-tool-choice`) for tools, or tool calls come back as raw text
2. Pass `reasoning_effort` (`high`, `medium` or `low`) and `tool_call_format` inside `chat_template_kwargs`. Other values return a template error
3. Send each earlier assistant turn back with `reasoning_content` as a string, even an empty one. A missing or null thinking field makes the template raise an error
4. Send your own system message, or set `default_system_prompt` to an empty string. Without one the template inserts an identity prompt naming IFM, Inception42 and Cerebras
5. Budget at least 32,768 output tokens at `high` effort, which the cards recommend for every request

### StepFun API

1. Set `max_tokens` yourself. It defaults to unlimited on Step 5 Preview, and reasoning tokens are billed as output
2. Use `response_format` with `type: json_schema` and `strict: true` when the shape matters. JSON Mode alone isn't schema-checked
3. Back off and retry on 429, 500, 503 and 504. The docs give no Retry-After header or backoff schedule
4. Expect HTTP 451 or `finish_reason: content_filter` when content fails StepFun's review, and don't retry the same input
5. Use api.stepfun.ai for the international platform. api.stepfun.com is the China platform with yuan pricing

## Questions

### Which is better for AI agents, Jais 3 or StepFun API?

Jais 3 scores 51.7 (D) on agent readiness against StepFun API's 44.1 (E), and leads in 4 of 7 scored categories. StepFun API leads on security & auth and transparency & trust.

### Do Jais 3 and StepFun API need an API key?

Jais 3 needs no key. StepFun API needs an API key.

### Can an agent call Jais 3 and StepFun API without installing anything?

No hosted endpoint is listed for Jais 3. StepFun API has a hosted endpoint at https://api.stepfun.ai/v1.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/jais-3-vs-stepfun-api.json, and with the fewest tokens: https://www.anchorterminal.com/compare/jais-3-vs-stepfun-api.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "jais-3", "b": "stepfun-api"}`. From a terminal: `anchor compare jais-3 stepfun-api`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/jais-3.json and https://www.anchorterminal.com/api/v1/tools/stepfun-api.json

## Other comparisons with Jais 3 or StepFun API

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- [Claude API vs StepFun API](https://www.anchorterminal.com/compare/anthropic-api-vs-stepfun-api.md)
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- [Cloudflare Workers AI vs Jais 3](https://www.anchorterminal.com/compare/cloudflare-workers-ai-vs-jais-3.md)
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