Osto encrypts both legs of every request — between the user and Osto, and between Osto and your origin. There are two ways to control which certificate Osto presents:Documentation Index
Fetch the complete documentation index at: https://docs.osto.one/llms.txt
Use this file to discover all available pages before exploring further.
- Auto-generate — Osto provisions and renews a free SSL certificate for you (ACME-based, requires a one-time CNAME at your DNS provider).
- Bring your own — you upload your own certificate bundle and Osto uses it.
Path: Assets → Domains → Manage Certificate
The certificate list
| Column | What it shows |
|---|---|
| Name | The name of the certificate (derived from the bundle or the domain it serves). |
| Valid To | The certificate’s expiry date. |
| Status | Current state — e.g. active, expired. |
| Managed By | Whether Osto auto-generated and manages this certificate, or you uploaded it. |
| Actions | Delete only — see Editing below. |
Adding an SSL Certificate
Certificates land in your pool from two places:- Directly here, via Add Certificate + on this page.
- Inside the Add Website wizard, when you uncheck Auto-generate certificate and upload a ZIP — that upload is added to the pool for future reuse.
Upload your certificate archive
In the Upload Certificate Archive dialog, drag-and-drop or click to upload a
.zip file containing your certificate bundle.The ZIP must contain valid certificate files (.crt or .pem) and private key files (.key or .pem).The upload accepts only a single
.zip file. If you have separate cert and key files, package them together into a ZIP before uploading.Editing a certificate
There is no edit action on this page. To replace or update a certificate (for instance after renewal), delete the existing one and upload the new one. Domains that referenced the old certificate will pick up the new one automatically, as long as the new cert covers the same domain.Deleting a certificate
- Click the Delete button on the certificate’s row.
- Confirm.
Tips
- Wildcard certificates simplify operations. One
*.example.comupload covers every subdomain you register. Use them unless you have a compliance reason to issue per-host. - Don’t have a certificate? Use the Auto-generate certificate option in Add Website — Osto handles provisioning and renewal for you.
- Track your own renewal cycle for uploaded certs. Osto surfaces expiry in the Valid To and Status columns and in alerts, but renewal happens at your CA.
Related
- Managing Websites & Subdomains — the Add Website wizard step that uses these certs (and where the auto-generate flow lives).
- What is Web Application Protection — how Osto’s dual-layer TLS works in practice.

