Step 2. Post the status Make a POST call to: https://[YOUR MASTODON SERVER]/api/v1/statuses?access_token=[YOUR ACCESS TOKEN] Set the type to application/x-www-form-urlencoded and pass the status field containing your status message. If you are attaching an image as well, pass the media_ids[] field with the media id you retrieved in the previous step. More info: Documentation for the /statuses endpoint on Mastodon.
URL form for a POST call to my Mastodon endpoints. Form submission with just status is enough. Repurpose jsonclassic.php for it.