Updated dnsapi2 (markdown)

dnsapi2.md

@@ -112,6 +112,7 @@
 - [188. Use Hetzner Cloud DNS API](#dns_hetznercloud)
 - [189. Use QUIC.cloud DNS API](#dns_qc)
 - [190. Use Infoblox UDDI DNS API](#dns_infoblox_uddi)
+- [191. Use HostUp DNS API](#dns_hostup)
 - [Use custom API](#dns_myapi)
 - [Use lexicon DNS API](#dns_lexicon)
 
@@ -2873,6 +2874,27 @@ To issue a cert:
 
 Report any bugs or issues [here](https://github.com/acmesh-official/acme.sh/issues/6645)
 
+<a name="dns_hostup"/>
+
+## 191. Use HostUp DNS API
+
+Create an API key in the HostUp panel with `read:dns`, `write:dns`, and `read:domains` scopes.
+
+```sh
+export HOSTUP_API_KEY="your_api_key"                  # required
+export HOSTUP_API_BASE="https://cloud.hostup.se/api"  # optional override
+export HOSTUP_TTL="60"                                # optional TTL (default 60s)
+export HOSTUP_ZONE_ID="1234"                          # optional: force a specific zone ID
+```
+
+Issue a cert:
+```sh
+./acme.sh --issue --dns dns_hostup -d example.com -d *.example.com --dnssleep 120
+```
+The variables above are saved in ~/.acme.sh/account.conf for reuse.
+
+Report any bugs or issues [here](https://github.com/hostup/acme.sh/issues/1).
+
 
 <a name="dns_myapi"/>