Prism Inference vs RouterPlus

Prism Inference

Three wire formats, a public OpenAPI 3.1 file, per-token prices in a keyless catalogue and zero data retention by default on every tier. The service launched on 24 September 2026 with two models, one of them by request, from a two-person company. No rate-limit numbers, SLA document, free tier or deprecation policy was found.

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.

Prism Inference

1. Call GET https://api.prisminference.com/v1/models at start-up, with no key, and use only ids it returns. Expect 403 on gemma-4-31b without organisation access
2. Use base URL https://api.prisminference.com/v1 for OpenAI clients and https://api.prisminference.com with no /v1 for Anthropic clients
3. Read error.retryable before retrying, and wait for Retry-After on 429, which covers both key limits and model capacity
4. Send reasoning_effort: "none" or low when latency matters. Reasoning is on by default and its tokens are billed as output
5. Keep conversation state yourself and send store: false on Responses. previous_response_id, stored responses and hosted tools aren't supported

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