Task: Check for preview for a link 

n8n workflow JSON:
{"nodes":[{"name":"On clicking 'execute'","type":"n8n-nodes-base.manualTrigger","position":[310,300],"parameters":{},"typeVersion":1},{"name":"Peekalink","type":"n8n-nodes-base.peekalink","position":[510,300],"parameters":{"url":"https://n8n1.io","operation":"isAvailable"},"credentials":{"peekalinkApi":"Peekalink API Credentials"},"typeVersion":1},{"name":"IF","type":"n8n-nodes-base.if","position":[710,300],"parameters":{"conditions":{"string":[],"boolean":[{"value1":"={{$json[\"isAvailable\"]}}","value2":true}]}},"typeVersion":1},{"name":"Peekalink1","type":"n8n-nodes-base.peekalink","position":[910,200],"parameters":{"url":"={{$node[\"Peekalink\"].parameter[\"url\"]}}"},"credentials":{"peekalinkApi":"Peekalink API Credentials"},"typeVersion":1},{"name":"NoOp","type":"n8n-nodes-base.noOp","position":[910,400],"parameters":{},"typeVersion":1}],"connections":{"IF":{"main":[[{"node":"Peekalink1","type":"main","index":0}],[{"node":"NoOp","type":"main","index":0}]]},"Peekalink":{"main":[[{"node":"IF","type":"main","index":0}]]},"On clicking 'execute'":{"main":[[{"node":"Peekalink","type":"main","index":0}]]}}}