Documentation

The intelligent infrastructure layer for AI inference.

One API, one key, one bill. The gateway speaks the OpenAI wire format and routes each request across multiple providers and models with automatic fallback, streaming, cost accounting and observability.

Quick Start OpenAPI reference Get an API key

Base URL https://api.smartapihub.com/v1

first request

curl https://api.smartapihub.com/v1/chat/completions \
  -H "Authorization: Bearer $LLM_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"openai/gpt-4o-mini","messages":[{"role":"user","content":"Hello"}]}'

OpenAI-compatible

Point the official openai SDK at the gateway. Same request and response shapes, plus a few X-LLM-* extras.

Routing & fallback

Every request is routed across providers by priority, cost, latency or availability, with retries and fallback before the first token.

Streaming

Standard SSE with ping comments, a guaranteed final usage chunk and a documented mid-stream error shape.

Every modality

Chat, responses, embeddings, images, speech, transcription — plus async video and music jobs with webhooks.

One bill, one key

Integer micro-USD pricing, discounts and per-key budgets. Cost is returned on every response.

Secure by default

Hashed keys, IP allow-lists, SSRF-guarded URLs, signed webhooks, secrets never logged.

Browse the documentation

Getting started

Quick Start
Get a key, make a chat completion, stream, switch model.
Authentication
Bearer keys, scopes, budgets, expiry and rotation.
Models
List models, pricing fields, capabilities, id format.
Migrating from OpenAI
Change baseURL, key and model id.

Text

Chat Completions
Request fields, routing extension, response and headers.
Responsespartial
Supported subset of the Responses API.
Streaming
SSE wire format, usage chunk, errors, fallback rules.
Embeddings
Vector embeddings, OpenAI shape.

Media

Image Generation
Generations and edits, response formats, signed URLs.
Audio
Speech synthesis streaming and transcriptions.
Video
Async jobs: 202, polling, cancel, webhooks, state machine.
Music
Async music generation jobs.

Platform

Routing
Strategies, per-request override, decision exposure.
Fallbacks
Retryable vs non-retryable, backoff, streaming rule.
Rate Limits
Scopes, headers, backing off.
Pricing
Micro-USD, list vs discount vs charged, savings.
API Keys
Key management concepts, limits, budgets, 402 vs 429.
Errors
The envelope and every error code.

Reference

SDK Examples
curl, TypeScript, Python, raw fetch/requests streaming.
OpenAPI
Interactive reference and endpoint index.