The Queue

When a user wants a stablecoin that isn't currently in supply, they can get in line for it. The queue is processed in strict FIFO (First In, First Out) order.

How it works

Getting in line is simple: specify which stablecoin you want and how much. Your spot is held until either:

• The stablecoin becomes available and you receive it
• You leave the line

If you leave, you can withdraw any available stablecoin instantly. If you want to get back in line, you go to the back.

Queue for USDC:
  Position 1: Alice wants 500 USDC
  Position 2: Bob wants 1,000 USDC
  Position 3: Carol wants 200 USDC

Someone supplies 800 USDC:
  → Alice receives 500 USDC (leaves queue)
  → Bob receives 300 USDC (still in line for 700 more)
  → Carol still waiting

Queue for USDC (after):
  Position 1: Bob wants 700 USDC
  Position 2: Carol wants 200 USDC

Partial fills

Positions can be partially filled. When this happens:

• The user receives the partial amount immediately
• The position remains in queue for the rest
• The QueueFilled event shows both filled and remaining amounts

Leaving the queue

Users can leave the queue at any time:

dollarStore.cancelQueue(positionId);

After leaving, users can immediately withdraw any stablecoin that's available in supply. If they want to get back in line for a specific stablecoin, they join at the back.

Queue limits

Parameter	Value	Purpose
Max positions	150	Prevents unbounded gas costs
Min order (base)	$100	Prevents spam at low queue depth
Min order scaling	10x per 25 positions	Higher minimums as queue grows

Minimum order scaling

The minimum order size increases as the queue gets deeper:

Queue positions	Minimum order
0-24	$100
25-49	$1,000
50-74	$10,000
75-99	$100,000
100-124	$1,000,000
125-149	$10,000,000

This prevents queue spam and ensures positions are meaningful at scale.