# RouterPlus vs StepFun API

> RouterPlus scores 51.2 (D) to StepFun's 44.1 (E) for llm inference. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/routerplus-vs-stepfun-api
- Markdown: https://www.anchorterminal.com/compare/routerplus-vs-stepfun-api.md (~2,800 tokens)
- Slim: https://www.anchorterminal.com/compare/routerplus-vs-stepfun-api.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/routerplus-vs-stepfun-api.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-13

RouterPlus scores 51.2 (D) on agent readiness against StepFun API's 44.1 (E), and leads in 5 of 7 scored categories. StepFun API leads on maintenance & community and transparency & trust. Both do llm inference.

- RouterPlus: grade D, 51.2/100, rank #777 of 1010. Markdown https://www.anchorterminal.com/tools/routerplus.md · JSON https://www.anchorterminal.com/api/v1/tools/routerplus.json
- StepFun API: grade E, 44.1/100, rank #907 of 1010. 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 190 models comparisons: https://www.anchorterminal.com/compare/inference/index.md

## Which one, for what

### RouterPlus (D)

Good for: Teams that call Claude and GPT models from one key and want the cost of every call in the response, with their own provider keys where they have them.

Ahead on:
- Reliability, 45 against 28
- Schema & documentation, 59 against 53
- Security & auth, 62 against 41
- Payments & pricing, 40 against 20

Watch for: No terms of service, privacy policy, status page, changelog or security.txt found for the gateway

### 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:
- Maintenance & community, 50 against 44
- Transparency & trust, 55 against 38

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


## Score by category

| Category | Weight | RouterPlus | StepFun API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 45 | 28 | RouterPlus +17 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 59 | 53 | RouterPlus +6 |
| Agent ergonomics | 13% (16.2 this run) | 71 | 68 | RouterPlus +3 |
| Security & auth | 14% (17.5 this run) | 62 | 41 | RouterPlus +21 |
| Payments & pricing | 10% (12.5 this run) | 40 | 20 | RouterPlus +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 44 | 50 | StepFun API +6 |
| Transparency & trust | 7% (8.8 this run) | 38 | 55 | StepFun API +17 |
| Negative events | ≤15 | -2 | 0 | |
| **Total** | | **51.2 · D** | **44.1 · E** | |

## Facts side by side

| Fact | RouterPlus | StepFun API |
| --- | --- | --- |
| Kind | Model router | Model API |
| Vendor | RouterPlus | StepFun |
| Hosted endpoint | `https://api.routerplus.com/v1` | `https://api.stepfun.ai/v1` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | Closed service. No terms of service for the gateway were found on routerplus.com or app.routerplus.com on 13 October 2026. The only terms on the site govern the capacity request form and name EVO HQ Inc, a Delaware corporation (https://routerplus.com/capacity/terms/). | 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 | yes | yes |
| 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 |

## Verdicts

**RouterPlus.** The docs are written for agents, every model price is public, and each response carries its own cost. No terms of service, privacy policy, status page or changelog were found. Signup adds no free credit, and the chat catalogue is Claude and GPT only.

**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

### RouterPlus

1. Send `max_tokens` on every request. Without it the balance hold assumes up to 32,768 output tokens and can return `insufficient_quota` on a small balance
2. Switch on `error_type`. Retry `rate_limit` after `retry-after`, and stop on `insufficient_quota`, which needs a person to add credit or raise a cap
3. Don't add a retry loop on top of the SDK's. There is no idempotency key, so a retry that reaches a provider is billed again
4. Copy model ids from `GET /v1/models` or /api/models.json. An unknown id is a 404 and the gateway never substitutes one
5. Use `/v1/messages` for Claude when you need `thinking` or server tools, and `/v1/chat/completions` with `response_format` only for GPT ids

### 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, RouterPlus or StepFun API?

RouterPlus scores 51.2 (D) on agent readiness against StepFun API's 44.1 (E), and leads in 5 of 7 scored categories. StepFun API leads on maintenance & community and transparency & trust.

### Do RouterPlus and StepFun API need an API key?

Both need an API key.

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

Yes. RouterPlus has a hosted endpoint at https://api.routerplus.com/v1 and StepFun API at https://api.stepfun.ai/v1.


## For agents

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

## Other comparisons with RouterPlus or StepFun API

- [Claude API vs RouterPlus](https://www.anchorterminal.com/compare/anthropic-api-vs-routerplus.md)
- [Claude API vs StepFun API](https://www.anchorterminal.com/compare/anthropic-api-vs-stepfun-api.md)
- [Antseed vs StepFun API](https://www.anchorterminal.com/compare/antseed-vs-stepfun-api.md)
- [BlockRun.AI vs RouterPlus](https://www.anchorterminal.com/compare/blockrun-ai-vs-routerplus.md)
- [BlockRun.AI vs StepFun API](https://www.anchorterminal.com/compare/blockrun-ai-vs-stepfun-api.md)
- [Cloudflare AI Gateway vs RouterPlus](https://www.anchorterminal.com/compare/cloudflare-ai-gateway-vs-routerplus.md)
- [Cloudflare AI Gateway vs StepFun API](https://www.anchorterminal.com/compare/cloudflare-ai-gateway-vs-stepfun-api.md)
- [Cloudflare Workers AI vs RouterPlus](https://www.anchorterminal.com/compare/cloudflare-workers-ai-vs-routerplus.md)
- [Cloudflare Workers AI vs StepFun API](https://www.anchorterminal.com/compare/cloudflare-workers-ai-vs-stepfun-api.md)
- [Cohere Chat API (Command models) vs RouterPlus](https://www.anchorterminal.com/compare/cohere-chat-vs-routerplus.md)
- [Cohere Chat API (Command models) vs StepFun API](https://www.anchorterminal.com/compare/cohere-chat-vs-stepfun-api.md)
- [DeepInfra vs RouterPlus](https://www.anchorterminal.com/compare/deepinfra-vs-routerplus.md)
- [DeepInfra vs StepFun API](https://www.anchorterminal.com/compare/deepinfra-vs-stepfun-api.md)
- [DeepSeek API vs RouterPlus](https://www.anchorterminal.com/compare/deepseek-api-vs-routerplus.md)
- [DeepSeek API vs StepFun API](https://www.anchorterminal.com/compare/deepseek-api-vs-stepfun-api.md)
- [Gemini Developer API vs RouterPlus](https://www.anchorterminal.com/compare/gemini-api-vs-routerplus.md)
- [Gemini Developer API vs StepFun API](https://www.anchorterminal.com/compare/gemini-api-vs-stepfun-api.md)
- [GroqCloud vs RouterPlus](https://www.anchorterminal.com/compare/groq-vs-routerplus.md)
- [GroqCloud vs StepFun API](https://www.anchorterminal.com/compare/groq-vs-stepfun-api.md)
- [Meta Model API vs RouterPlus](https://www.anchorterminal.com/compare/meta-model-api-vs-routerplus.md)
- [Meta Model API vs StepFun API](https://www.anchorterminal.com/compare/meta-model-api-vs-stepfun-api.md)
- [Mistral AI API vs RouterPlus](https://www.anchorterminal.com/compare/mistral-api-vs-routerplus.md)
- [Mistral AI API vs StepFun API](https://www.anchorterminal.com/compare/mistral-api-vs-stepfun-api.md)
- [Novita AI vs RouterPlus](https://www.anchorterminal.com/compare/novita-ai-vs-routerplus.md)
- [Novita AI vs StepFun API](https://www.anchorterminal.com/compare/novita-ai-vs-stepfun-api.md)
- [OpenAI API vs RouterPlus](https://www.anchorterminal.com/compare/openai-api-vs-routerplus.md)
- [OpenAI API vs StepFun API](https://www.anchorterminal.com/compare/openai-api-vs-stepfun-api.md)
- [OpenRouter vs RouterPlus](https://www.anchorterminal.com/compare/openrouter-vs-routerplus.md)
- [OpenRouter vs StepFun API](https://www.anchorterminal.com/compare/openrouter-vs-stepfun-api.md)
- [Prism Inference vs RouterPlus](https://www.anchorterminal.com/compare/prism-inference-vs-routerplus.md)
- [Prism Inference vs StepFun API](https://www.anchorterminal.com/compare/prism-inference-vs-stepfun-api.md)
- [RouterPlus vs SambaCloud](https://www.anchorterminal.com/compare/routerplus-vs-sambanova.md)
- [RouterPlus vs SiliconFlow](https://www.anchorterminal.com/compare/routerplus-vs-siliconflow.md)
- [SambaCloud vs StepFun API](https://www.anchorterminal.com/compare/sambanova-vs-stepfun-api.md)
- [SiliconFlow vs StepFun API](https://www.anchorterminal.com/compare/siliconflow-vs-stepfun-api.md)
- [Antseed vs RouterPlus](https://www.anchorterminal.com/compare/antseed-vs-routerplus.md)