Unified LLM API
One managed account for a changing model stack
A unified LLM API gives your application one account and authentication layer for multiple model makers. It does not mean every model has the same capability or endpoint; KeepRouter publishes the supported route on every model page.
Last reviewed 2026-08-15 · Editorial review: KeepRouter Editorial
What is unified
Your KeepRouter key authenticates requests to the models exposed in the production catalog. Compatible chat models can accept OpenAI-style Chat Completions or Anthropic-style Messages requests. Image generation, embeddings, speech, transcription, and other specialized modalities use the route shown on their model page.
That boundary matters. A trustworthy unified API normalizes the parts that can be normalized—account, key, catalog, billing, and compatible request shapes—without pretending that an image model and a chat model share one universal payload.
The working contract
- Discover: use the model catalog to verify ID, maker, modality, endpoint, and current customer price.
- Authenticate: create one
sk-kr-key, optionally scoped to a model allowlist and spending limit. - Call: keep the client format supported by the selected model and point its base URL at KeepRouter.
- Measure: inspect request status, token usage, cost, cache state, and latency in the console.
- Change: switch the model ID only after checking that the replacement supports the same route and features.
Where this reduces work
The account and billing relationship stays stable while a team evaluates different model makers. A prototype can begin with the published free model, record a representative request, then compare paid candidates using the same usage view. Production code keeps a bounded set of client integrations instead of adding a new billing account and secret for every experiment.
Where your application still owns decisions
Model behavior, context limits, tool semantics, safety settings, and output quality are not interchangeable. KeepRouter exposes routing and protocol compatibility; your tests decide whether a model is suitable. Store model choice in configuration, run a reproducible evaluation, cap output tokens, and handle provider-shaped errors even when the client format is stable.
Start with evidence
Run the quickstart against free, then open the request in Usage. Once authentication, streaming, and error handling are proven, choose a paid model from the live catalog and set a key-level model allowlist before adding credit.
Frequently asked questions
Does one API mean one endpoint for every model?
No. Compatible chat models share supported client formats, while specialized modalities use their documented route-specific endpoints.
Do I need a separate provider account?
Not for models purchased through KeepRouter's managed catalog. You fund prepaid KeepRouter credit and use a KeepRouter key.
Can I restrict a key to specific models?
Yes. Self-serve keys support a model allowlist and optional spend controls so an application does not automatically inherit the whole catalog.
Where do I check current model availability?
Use the live model catalog and each model detail page. Static marketing pages do not preserve a model-count or price snapshot.