Signed URLs
HMAC-SHA256 covers the method, path, and canonical query. Your secret never belongs in browser code or a public page.
Open Graph as an API
Generate dynamic og:image URLs.
FastOG turns signed query parameters into branded social preview images for product pages, blog posts, SaaS pages, and other links. Keep the HMAC secret on your server and put the returned URL in your page metadata.
Template props
Pass titles, branding, colors, product prices, ratings, badges, and image URLs to the template that fits the page.
Framework examples
Use the single-file signer examples for Node.js, Svelte, PHP, Ruby, Python, or Go, then embed the resulting URL as og:image.
The request model
GET /api/v1/og?template=product&title=...&key=...&s=...- 1. Build the query. Include the template and content props you want rendered.
- 2. Sign it server-side. Use the HMAC-SHA256 canonicalization contract.
- 3. Embed the result. Set the signed URL as the page's
og:image.
Common questions
What does the FastOG API generate?
FastOG generates Open Graph images from signed GET URLs. The default canvas is 1200x630, and templates can receive titles, subtitles, branding, colors, product data, and image URLs.
How is an API URL authenticated?
A server creates a signature with HMAC-SHA256 using the HTTP method, API path, and canonical query. The secret stays on your server; the public key and signature are placed in the image URL.
Can I use FastOG in Next.js or another framework?
Yes. The repository publishes single-file signer examples for Node.js, Svelte, PHP, Ruby, Python, and Go, with framework tutorials for common web stacks.
Is the Dynamic API metered like Studio exports?
They are separate products in the current configuration. Dynamic API access requires an active API subscription and renders are unmetered; Studio is the separate prepaid static PNG export product.