Developer URL helpers

Lightweight og image api helpers for building Dynamic OG Image API URLs. This is not a full SDK and is not published to npm.

This Hostinger build does not serve /api/og. Use the builder with a Cloudflare Pages origin, or generate PNGs in the browser with the OG Image Generator.

URL builder

Astro

---
import { buildOgApiUrl } from "../lib/og-sdk/url";
const og = buildOgApiUrl("https://socialimagekit.com", {
  title: "Ship better link previews",
  subtitle: "1200×630",
  template: "kit-feature",
  theme: "midnight",
});
---
<meta property="og:image" content={og} />

Next.js

import { buildOgApiUrl } from "@/lib/og-sdk/url";

export default function Page() {
  const og = buildOgApiUrl(process.env.NEXT_PUBLIC_OG_ORIGIN!, {
    title: "Launch notes",
    template: "blog-rule",
    format: "png",
  });
  return <meta property="og:image" content={og} />;
}

React

import { buildOgApiUrlStrict } from "./og-sdk/url";

const src = buildOgApiUrlStrict("https://socialimagekit.com", {
  title: "Weekly digest",
  template: "dispatch-digest",
  theme: "forest",
});
// <img src={src} width={1200} height={630} alt="" />

Plain HTML

<!-- Cloudflare origin only -->
<img
  src="https://socialimagekit.com/api/og?title=Hello&amp;template=kit-feature&amp;theme=indigo&amp;format=png"
  width="1200"
  height="630"
  alt=""
/>

Errors

  • invalid_params / unknown_template / unknown_font / invalid_color / invalid_size — JSON error body with short TTL cache.
  • Max title 120, subtitle 160, width 1200, height 630. No remote image URLs in v1.
  • Rate limited (~30/min/IP on Cloudflare). Not a guaranteed SLA.

Frequently asked questions

Short answers about OG images, sizes, missing previews and how this free site works.

Is this an npm package?

No. Helpers live in the open-source site repo (src/lib/og-sdk/url.ts). Copy the functions or import them in this monorepo. We do not auto-publish to npm.

Does /api/og work on Hostinger?

No. Hostinger builds ship PHP preview only. Dynamic /api/og requires Cloudflare Pages Functions. Point the URL builder at a Cloudflare origin if you use that stack.

Are there API keys?

Not for the free public endpoint. Rate limits and size caps apply. Do not claim unlimited uptime.

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