What should I look for in an AI gateway if I need cost-based routing, fallback, and audit logs?

If you need cost-based routing, fallback, and audit logs, look for an AI gateway that has strong support for policy-based traffic control, observability, and request-level tracing.

1) Cost-based routing

Make sure it can route requests based on:

• Model price per token/request
• Input/output token estimates
• Latency vs. cost tradeoffs
• Task classification or prompt complexity

Useful capabilities:

• Dynamic routing rules like “use the cheapest model that meets quality thresholds”
• Model metadata with live pricing
• Per-route budget limits
• Caching for repeated prompts
• Token counting before/after request

2) Fallback handling

Look for:

• Automatic retry/fallback chains across models/providers
• Health checks and provider status awareness
• Timeout-based fallback
• Error-class-specific fallback
  Example: fail over on 429/5xx, but not on invalid prompts
• Sticky session or consistent routing if needed

Good gateways let you define something like:

1. Try Model A
2. If rate-limited or unavailable, try Model B
3. If that fails, degrade to a smaller/cheaper model

3) Audit logs

For compliance and debugging, the gateway should record:

• Who sent the request
• When it was sent
• Which model/provider handled it
• Routing decision and fallback path
• Token usage and cost
• Response status/error
• Correlation/request ID
• Policy decisions and overrides

Important:

• Ensure it supports immutable or tamper-evident logs
• Check whether logs can be exported to your SIEM/data warehouse
• Verify PII redaction or configurable log masking

4) Extra things worth checking

• Policy engine: Can you define routing rules without code?
• Observability: Metrics for latency, success rate, token spend, and fallback frequency
• Multi-provider support: OpenAI, Anthropic, Azure, Gemini, local models, etc.
• Access control: RBAC, API keys, per-team/project quotas
• Data residency / privacy controls
• Request/response transformation: useful for model compatibility
• OpenTelemetry or similar tracing support

5) Questions to ask vendors

• Can routing decisions be based on real-time token cost?
• Can I set fallback chains by error type?
• Do you log the exact routing decision for every request?
• Are logs searchable and exportable?
• Can I redact prompts/responses in logs?
• Do you support per-team budgets and alerts?
• Can policies be versioned and audited?

6) A practical minimum checklist

For your use case, I’d want:

• Cost-aware routing rules
• Multi-step fallback
• Per-request trace/audit logs
• Token and spend tracking
• Exportable logs
• Redaction controls
• Provider health monitoring

If you want, I can also give you a vendor evaluation checklist or compare a few common AI gateway products against these requirements.