Step 15 / 20 · Reason · routing · cache

LLM gateway

Right model per task, fallback, prompt cache.

For business

What it is

One front door to every AI model: it picks the right model for each task, switches to a backup if one fails, and tracks cost.

Why it matters

No lock-in to a single provider, outages do not stop the business, and simple tasks do not run on expensive models.

Risk without it

One provider’s outage or price change becomes yours, and costs stay invisible until the invoice.

For engineers

How it works

Every model call goes through one service that handles routing (a small model to classify, a large one to draft), retries and fallback, rate limits, prompt caching, streaming, and cost and latency logging per run.

Typical stack

  • gateway service
  • LiteLLM-style routing
  • Anthropic / OpenAI / Bedrock APIs

Pitfalls & trade-offs

  • Fallback models need their own evals: their output differs.
  • Respect data-residency rules per provider.
  • Log tokens and cost per tenant and per feature.

In this example

In
assembled prompt
Out
model: large
fallback: ready
streaming …

Fictional sample · not a client system

Contact

Questions about this?

Book a call Write to hello@paxcode.it