API Overview

The Promptly REST API lets you fetch prompts directly over HTTP - no SDK required. Use it from any language or tool that can make HTTP requests.

Base URL

All API requests use the following base URL:

https://api.promptlycms.com

Authentication

Authenticate every request with a Bearer token in the Authorization header. Get your API key from the Promptly CMS dashboard.

Authorization: Bearer pk_live_...

Quick start

Get your API key

Copy your API key from the dashboard settings.
Make your first request
- curl
- fetch
Terminal window
curl https://api.promptlycms.com/prompts/your-prompt-id \ -H "Authorization: Bearer pk_live_..."
const response = await fetch( 'https://api.promptlycms.com/prompts/your-prompt-id', { headers: { Authorization: 'Bearer pk_live_...', }, }, ); const prompt = await response.json();

Use the response

The API returns JSON with the prompt content, model configuration, and template variables:

{
  "promptId": "your-prompt-id",
  "promptName": "My Prompt",
  "version": "1.0.0",
  "systemMessage": "You are a helpful assistant.",
  "userMessage": "Help ${name} with ${task}.",
  "config": {
    "model": "claude-sonnet-4.5",
    "temperature": 0.7,
    "schema": [],
    "inputData": null,
    "inputDataRootName": null
  }
}

CORS

The API supports CORS for all origins. Only GET and OPTIONS methods are allowed - the API is read-only.

REST API vs SDK

	REST API	TypeScript SDK
Language	Any	TypeScript/JavaScript
Type safety	Manual	Automatic (with codegen)
Model resolution	Manual	Automatic (AI SDK models)
Template interpolation	Manual string replacement	Built-in `userMessage()` function
Best for	Non-TypeScript apps, debugging, scripting	TypeScript apps with AI SDK

Next steps

Endpoints - full reference for all API endpoints
Rate Limits - usage quotas and rate limit headers
Errors - error codes and troubleshooting