Roll Modifier Question

I've been looking around for a way to add or subtract form a roll on crits or failures. For example when we roll a d20 if it is a 20 add 10. If it is a 1 minus 10. How would I go about doing this?

There isn't really a way to do this with a free account.  You'll need to do it manually. With a Pro Subscription, you could do this with an API script, or with a Custom Character Sheet's Roll Template.

Interesting my friend the DM has a pro account we are all just trying to help him out.  How would you do it then?

So, it will largely come down to interface.  The very simplest script I can write for this is: on('ready',()=>on('chat:message',(msg)=>{   if('api'===msg.type && /^!roll\b/i.test(msg.content)){     let roll = randomInteger(20);     let res = roll + (20===roll ? 10 : 0) - (1===roll ? 10 : 0);     sendChat(msg.who,`Roll: ${res}  (${roll})`);     } })); !roll This is probably not even close to what you need, but that shows how you can start to get there.