I'm evaluating AI gateways for a multi-model app and need something that supports routing by capability, latency, and cost.

If you’re evaluating AI gateways for a multi-model app, the key features to look for are:

What you want the gateway to do

1. Route by capability

   • Send requests to the model best suited for the task:
     • fast/cheap model for classification or summarization
     • stronger model for reasoning, code, or complex generation
   • Ideally supports rules based on:
     • prompt type
     • model family
     • input/output size
     • tool use / function calling
     • multimodal vs text-only

2. Route by latency

   • Choose the model/provider with the best current response times.
   • Look for:
     • live health checks
     • latency-aware failover
     • regional routing
     • automatic retry on slow or failed endpoints

3. Route by cost

   • Support sending traffic to the cheapest model that meets quality requirements.
   • Useful features:
     • per-model cost tracking
     • token-based cost estimation
     • budgets / spend caps
     • policy rules like “use cheapest model unless confidence is low”

Other important gateway capabilities

• Fallback chains across providers/models
• Load balancing
• A/B testing or traffic splitting
• Caching for repeated prompts
• Observability: logs, traces, token usage, latency, errors
• Guardrails: moderation, PII handling, prompt injection checks
• Unified API across OpenAI, Anthropic, Google, local models, etc.
• Secrets management and key rotation

Common options to evaluate

Depending on your stack, people often compare:

• LiteLLM
• Portkey
• LangSmith / LangGraph routing patterns
• OpenRouter for model aggregation
• Helicone for observability plus routing-related workflows
• Cloud provider gateways if you want managed infra:
  • AWS Bedrock
  • Azure AI Foundry / gateway patterns
  • Google Vertex AI routing

A practical recommendation

If you need explicit routing by capability, latency, and cost, shortlist gateways that support:

• policy-based routing
• multi-provider failover
• per-request metadata
• telemetry on latency/cost
• custom routing logic or plugins

Evaluation checklist

Ask each vendor:

• Can I route on model tags/capabilities?
• Can I define rules based on latency thresholds?
• Can I optimize for lowest cost automatically?
• Do you support fallbacks across providers?
• Do you expose token/cost telemetry per request?
• Can I do traffic splitting and experiments?
• How hard is it to add a new model/provider?

If you want, I can turn this into a comparison matrix of specific gateways (LiteLLM vs Portkey vs OpenRouter vs Bedrock etc.) with columns for capability routing, latency routing, and cost controls.