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Keln

API reference

Base URL: https://api.keln.ai/v1 · Auth: Authorization: Bearer sk-keln-…

Keln is OpenAI-wire-compatible, an OpenAI SDK works by changing the base URL. Behind the endpoint, Keln normalizes across providers, so whichever one serves your request, your parameters behave the same way and the response has the same shape.

Endpoints

Endpoint What it does
POST /v1/chat/completions Chat completions, streaming and non-streaming, tools, structured output, reasoning control. Needs an API key.
POST /v1/responses The OpenAI Responses schema, for agents and Codex. Same key, models, and prices as chat completions.
POST https://anthropic.keln.ai/v1/messages The Anthropic Messages schema, for Claude Code and Anthropic SDKs. Same key, models, and prices.
GET /v1/models The servable catalog: context windows, live pricing, input modalities (text / image), and current routing performance figures. No key needed, CORS-open.
GET /healthz Liveness check, for uptime monitoring. No key needed.

There is no legacy /v1/completions text endpoint.

Model ids are lowercase (deepseek-ai/deepseek-v4-flash) and matched case-insensitively.

Authentication

Every POST /v1/chat/completions requires an API key, created in the portal (Keys page):

Authorization: Bearer sk-keln-…

Keln shows each key once and stores only a hash, and you can revoke a key at any time. A key belongs to a workspace. Usage bills to that workspace's balance, and you can cap it with per-key budgets.

GET /v1/models requires no key and is served CORS-open (Access-Control-Allow-Origin: *).

SDKs

Any OpenAI-compatible client works:

from openai import OpenAI
client = OpenAI(base_url="https://api.keln.ai/v1", api_key="sk-keln-…")

import OpenAI from "openai";
const client = new OpenAI({ baseURL: "https://api.keln.ai/v1", apiKey: "sk-keln-…" });

Migrating from OpenAI or OpenRouter: Migration guide ↗

Reading order