Is There a UPCS SDK or Client Library?

No. UPCS does not provide official SDKs or client libraries for any language. There is no npm package, Composer package or Python package to install from UPCS. Integration is done with two documented building blocks.

Building block 1: REST calls

Every server-side call is a plain HTTPS request to https://api.upcs.io/api with an x-api-key header and, for POST requests, a JSON body:

• POST /v1/embed/sessions: create an embed session.
• POST /v1/embed/resolve: coordinates to a code.
• GET /v1/upcs/lookup/{code}: code to a location.
• POST /v1/upcs/generate: create a code for a point.

Any language with an HTTP client can do this. See examples for cURL, Node.js, PHP and Python.

Building block 2: the embed script

For the browser, load https://api.upcs.io/api/embed/upcs-embed.js and call UPCS.mount. It returns { iframe, destroy() }. See UPCS.mount options explained.

Writing your own thin wrapper

Because the surface is small, many teams write a single internal module:

// upcsClient.js - a tiny wrapper of your own, not an official SDK
const BASE = 'https://api.upcs.io/api';

async function call(method, path, body) {
  const res = await fetch(BASE + path, {
    method,
    headers: { 'x-api-key': process.env.UPCS_API_KEY, 'Content-Type': 'application/json' },
    body: body ? JSON.stringify(body) : undefined,
  });
  const data = await res.json().catch(() => ({}));
  if (!res.ok) throw Object.assign(new Error(data.message || 'UPCS error'),
    { status: res.status, code: data.code });
  return data;
}

export const lookup   = (code) => call('GET', '/v1/upcs/lookup/' + encodeURIComponent(code));
export const generate = (latitude, longitude) => call('POST', '/v1/upcs/generate', { latitude, longitude });

Centralising calls makes key rotation, caching and backoff a one-place change.

Plugins are not SDKs

Ready-made plugins exist for WordPress/WooCommerce, PrestaShop and OpenCart; they are store modules, not libraries. See the plugins page.