If you've come across pubsub-shard1-13-2.zendesk.com and wondered whether it's safe, the short answer is yes. This is a technical subdomain owned by Zendesk, the well-known customer support software company. It's not a consumer website — it's a backend endpoint used for their pubsub messaging system and health monitoring.
Because this isn't a site you'd shop from or log into, many of the usual trust signals (like a privacy policy or contact page) simply don't apply. What matters here is security and longevity, and both are strong. The connection is encrypted, the site has been recorded in the Wayback Machine since 2017, and it's hosted behind Cloudflare's infrastructure. No blacklists or threat flags exist.
In short, pubsub-shard1-13-2.zendesk.com is exactly what it looks like: a small piece of Zendesk's technical backbone. There's no evidence of a scam, and no reason to treat it with suspicion.