Slack Webhook Formatting

I am able to generate some nice webhooks thanks to this post by @MattHenry.

HOWEVER, my posts in slack are showing up as URL encoded. Here’s my Body:

{
	"blocks": [
		{
			"type": "header",
			"text": {
				"type": "plain_text",
				"text": "{Ticket.TicketNumber} - {Ticket.TicketSubject} ({Ticket.TicketPriority})",
				"emoji": true
			}
		},
		{
			"type": "divider"
		},
		{
			"type": "context",
			"elements": [
				{
					"type": "image",
					"image_url": "https://pbs.twimg.com/profile_images/625633822235693056/lNGUneLX_400x400.jpg",
					"alt_text": "cute cat"
				},
				{
					"type": "plain_text",
					"text": "{Ticket.TicketStatusName}. Response Time: {ServiceLevelAgreementResponseTime} | Resolution Time: {ServiceLevelAgreementResolutionTime}"
				}
			]
		},
		{
			"type": "section",
			"text": {
				"type": "plain_text",
				"text": "{Ticket.IssueDescription}"
			},
			"accessory": {
				"type": "button",
				"text": {
					"type": "plain_text",
					"text": "View Ticket",
					"emoji": true
				},
				"value": "open_ticket",
				"url": "https://MYORG.incidentiq.com/agent/tickets/open?flyout-type=agent-ticket&flyout-id={Ticket.TicketId}",
				"action_id": "button-action"
			}
		}
	]
}

FINALLY, does the Webhook simulator actually work for anyone? It says it sends the webhook, but it’s never recieved unless I actually create/update/resolve a real like ticket, which is tedious…