# Muse Spark Open vs RouterPlus

> Muse Spark Open scores 53.4 (D) to RouterPlus's 51.2 (D) for llm inference. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/muse-spark-open-vs-routerplus
- Markdown: https://www.anchorterminal.com/compare/muse-spark-open-vs-routerplus.md (~3,000 tokens)
- Slim: https://www.anchorterminal.com/compare/muse-spark-open-vs-routerplus.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/muse-spark-open-vs-routerplus.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
- Licence: CC BY 4.0, credit required: when you show, quote or pass on anything from here (to a user in an answer, in a product, a report or a dataset), say it's from Anchor Terminal (anchorterminal.com) and link the page or API address you took it from. Reviews also credit their author.
- Updated: 2026-10-15

Muse Spark Open scores 53.4 (D) on agent readiness against RouterPlus's 51.2 (D), and leads in 4 of 7 scored categories. RouterPlus leads on security & auth. Both do llm inference.

- Muse Spark Open: grade D, 53.4/100, rank #760 of 1095. Markdown https://www.anchorterminal.com/tools/muse-spark-open.md · JSON https://www.anchorterminal.com/api/v1/tools/muse-spark-open.json
- RouterPlus: grade D, 51.2/100, rank #816 of 1095. Markdown https://www.anchorterminal.com/tools/routerplus.md · JSON https://www.anchorterminal.com/api/v1/tools/routerplus.json
- Best model APIs and inference for AI agents: https://www.anchorterminal.com/best/inference/index.md
- All 210 models comparisons: https://www.anchorterminal.com/compare/inference/index.md

## Which one, for what

### Muse Spark Open (D)

Good for: A team with a four-GPU Blackwell node, or two to four Mac Studios, that wants a 1M-token multimodal coding and agent model on its own hardware with no prompts leaving it.

Ahead on:
- Payments & pricing, 50 against 40
- Maintenance & community, 60 against 44
- Transparency & trust, 53 against 38

Also in its favour:
- No key needed to call it

Watch for: The NVFP4 checkpoint (about 537 GB) serves on four B300 GPUs and the BF16 one (about 1.65 TB) on eight

### 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:
- Security & auth, 62 against 44

Also in its favour:
- A hosted endpoint, with nothing to install

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


## Score by category

| Category | Weight | Muse Spark Open | RouterPlus | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 42 | 45 | RouterPlus +3 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 61 | 59 | Muse Spark Open +2 |
| Agent ergonomics | 13% (16.2 this run) | 69 | 71 | RouterPlus +2 |
| Security & auth | 14% (17.5 this run) | 44 | 62 | RouterPlus +18 |
| Payments & pricing | 10% (12.5 this run) | 50 | 40 | Muse Spark Open +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 60 | 44 | Muse Spark Open +16 |
| Transparency & trust | 7% (8.8 this run) | 53 | 38 | Muse Spark Open +15 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **53.4 · D** | **51.2 · D** | |

## Facts side by side

| Fact | Muse Spark Open | RouterPlus |
| --- | --- | --- |
| Kind | Model API | Model router |
| Vendor | Meta | RouterPlus |
| Hosted endpoint | no (local only) | `https://api.routerplus.com/v1` |
| Transports | HTTP | HTTP |
| Auth | None | API key |
| Pricing | Free | Pay per use |
| x402 | no | no |
| Licence | Muse Model Licence (source-available weights, not an OSI licence), free of charge with an attribution notice, a separate agreement with Meta before Model as a Service by a licensee group above $20M gross revenue, and the Muse Spark Open Usage Policy | 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/). |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-15 | none |
| Terms last updated |  | no document linked |
| Privacy policy last updated | no document linked | no document linked |
| Customer content may train models |  |  |
| Terms restrict automated access |  |  |
| Terms restrict benchmarking |  |  |
| Terms or service can change without notice |  |  |
| Arbitration or class-action waiver |  |  |

## Verdicts

**Muse Spark Open.** Muse Spark Open runs on the owner's hardware in seven runtimes, with OpenAI-compatible servers in vLLM and SGLang, standard tool calls, a 1M-token context and Meta's own serving docs. Serving the 537 GB NVFP4 checkpoint takes four B300 GPUs, Meta's download is gated by manual review, and the licence adds attribution and a revenue threshold for model resellers.

**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.

## Before you call either

### Muse Spark Open

1. Start vLLM or SGLang with `--reasoning-parser muse --tool-call-parser muse` (vLLM also `--enable-auto-tool-choice`), or tool calls come back as raw text
2. Set `reasoning_effort` to `low` or `medium` for short tasks. The default is `xhigh`, reasoning can't be turned off, and other values return an error
3. Stop only on `<|eot|>` and end of text. Stopping on `<|eom|>` cuts off tool calls and final answers
4. Stream long generations and leave `max_tokens` room for reasoning, or `content` can come back empty with `finish_reason` `length`
5. Don't call Meta Model API for this model. Use a self-hosted server or a hosted provider's model string, such as `meta-models/muse-spark-open`

### 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

## Questions

### Which is better for AI agents, Muse Spark Open or RouterPlus?

Muse Spark Open scores 53.4 (D) on agent readiness against RouterPlus's 51.2 (D), and leads in 4 of 7 scored categories. RouterPlus leads on security & auth.

### Do Muse Spark Open and RouterPlus need an API key?

Muse Spark Open needs no key. RouterPlus needs an API key.

### Can an agent call Muse Spark Open and RouterPlus without installing anything?

No hosted endpoint is listed for Muse Spark Open. RouterPlus has a hosted endpoint at https://api.routerplus.com/v1.


## For agents

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

## Other comparisons with Muse Spark Open or RouterPlus

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