Setting up Demfilz Shipping Rates for Australia Post

Before you start

There are two ways to get rates — you only need one:

• PAC API (easiest) — a single free API key that returns standard retail postage. Register at developers.auspost.com.au and request the Postage Assessment Calculation (PAC) API.
• Shipping & Tracking API (account rates) — uses your Australia Post charge-account number, API key and password to return your negotiated rates (eParcel / MyPost Business / Enterprise).

Step 1 — Install & activate

• In WordPress admin, go to Plugins → Add New → Upload Plugin.
• Choose the plugin .zip, click Install Now, then Activate.
• If WooCommerce isn't active yet, install and activate it first — this plugin depends on it.

After activating, a new tab appears at WooCommerce → Settings → Australia Post. Everything below is configured there.

Step 2 — Connect Australia Post

• Rate source — choose PAC API or Shipping & Tracking API. The credential fields update to match.
• Enter credentials — for PAC, paste the API key (AUTH-KEY); for the account API, enter your account number, API key and password.
• Save changes. Credentials are stored masked — once saved, the field shows a placeholder; leave it blank to keep the stored value.
• Click "Test credentials". The plugin sends a sample Sydney → Melbourne quote and tells you immediately whether your credentials work.

Step 3 — Set your origin & packaging

• Origin postcode — where you dispatch from (e.g. 2000). Falls back to your WooCommerce store postcode.
• Use product dimensions — when on, parcel size is calculated from your products' length/width/height (when every item has them set).
• Default weight & box — fallback values for items without weight or dimensions. Set a realistic default box in centimetres.

Cart weights are summed and converted to kilograms automatically; dimensions are converted to centimetres for Australia Post.

Step 4 — Choose services, fees & options

• Enabled services — tick the services to offer (Parcel Post, Express, Courier, satchels, international). Leave empty to show everything Australia Post returns. A service only appears if it's valid for that parcel's size, weight and destination.
• Handling fee & markup — a flat fee per order and/or a percentage on top of the Australia Post price.
• Delivery time estimate — optionally append an indicative delivery window to each service.
• Remove GST — strip the 10% GST from quoted prices (useful if you add tax separately via WooCommerce).
• Free shipping — optionally offer a free option once the cart subtotal hits a threshold.
• Fallback rate — a flat rate offered only if the API is briefly unreachable, so checkout is never blocked.

Step 5 — Add Australia Post to a shipping zone

WooCommerce only quotes a method once it's added to the zone a customer ships to.

• Go to WooCommerce → Settings → Shipping and open the relevant zone (e.g. "Australia"), or add one.
• Click Add shipping method, choose Australia Post, and add it.
• Open the method's settings to set the title customers see and the tax status. Leave tax status on None — Australia Post domestic prices already include GST, so "Taxable" would charge GST twice.

Step 6 — Test before going live

• Turn on Test mode (admin only) — live rates then show only to logged-in administrators while you check.
• Add a product with a real weight and run a checkout to an Australian address, and an international one, to confirm the right services and prices appear.
• If something's off, enable Debug logging and review WooCommerce → Status → Logs.
• Happy? Turn Test mode off — you're live.

Settings reference

Troubleshooting

No rates appear at checkout

Check, in order: credentials are saved and "Test credentials" succeeds; an origin postcode is set; the Australia Post method is added to the customer's zone; products have a weight; and if you set an enabled-services list, that those services are actually available for the parcel and destination.

The shipping price looks doubled

Australia Post domestic prices already include GST. If WooCommerce also adds tax, customers pay it twice. Set the method's tax status to None, or enable Remove GST if you intend to add tax yourself.

A specific service isn't showing

Australia Post only returns services valid for the exact parcel — an Express satchel won't appear for a parcel heavier or larger than that satchel allows. Try a smaller test parcel, or leave the service list empty to see everything.

Rates seem out of date

Responses are cached to keep checkout fast. Lower the cache duration under Advanced, or set it to 0 while testing, then raise it for production.

The plugin won't activate

It requires WooCommerce to be installed and active. Activate WooCommerce first, then this plugin.