# LLM & API glossary

Markdown version of https://kymaapi.com/glossary, for agents and crawlers. Same content as the HTML page.

- Generated: 2026-10-28T21:43:30.496Z
- HTML page: https://kymaapi.com/glossary
- Model catalog: https://kymaapi.com/models.md
- Pricing: https://kymaapi.com/pricing.md

Plain-language definitions of the concepts behind a modern LLM API gateway: what they mean, why they matter, and how Kyma implements them.

- [LLM gateway · Read → · An LLM gateway is a single API endpoint that routes requests to many language models behind one key, one bill, and one interface.](https://kymaapi.com/glossary/llm-gateway)
- [LLM router · Read → · An LLM router automatically directs each request to an appropriate model or backend based on availability, cost, capability, or a routing rule.](https://kymaapi.com/glossary/llm-router)
- [Prompt caching · Read → · Prompt caching reuses a model's computation for repeated prompt prefixes, billing the cached input at a fraction of the normal rate.](https://kymaapi.com/glossary/prompt-caching)
- [Model aliases · Read → · A model alias is a short name that a gateway resolves to a concrete model, instead of an exact model id.](https://kymaapi.com/glossary/model-aliases)
- [LLM failover · Read → · LLM failover automatically retries a failed request on a backup so a single model or backend outage doesn't surface to your users as an error.](https://kymaapi.com/glossary/llm-failover)
- [Tool calling · Read → · Tool calling (also called function calling) lets a model request that your code run a named function with arguments, then continue with the result. This is the foundation of AI agents.](https://kymaapi.com/glossary/tool-calling)
- [Structured outputs · Read → · Structured outputs constrain a model to return valid JSON that matches a schema you provide, so downstream code can parse it reliably.](https://kymaapi.com/glossary/structured-outputs)
- [Pay-per-token pricing · Read → · Pay-per-token pricing bills by the number of input and output tokens a request uses, with no subscription or seat fee: you pay only for what you consume.](https://kymaapi.com/glossary/pay-per-token)

Start building with $0.50 free credit on the free tier. · [Get API key →](https://kymaapi.com/signup)