Call pricing and fees

The Alarm service operates under a scheduler pays model, which means that the scheduler of a call is responsible for paying for the full gas cost and fees associated with executing the call.

This payment is automatic and happens during the course of the execution of the scheduled call.

Minimum Balance

In order to guarantee reimbursment of gas costs and payment to the account which executes the scheduled call, the scheduler of the call must have an account balance sufficient to pay for the call at the time of execution. Since, it is unknown how much gas the call will consume the Alarm service requires a minimum balance equal to the maximum possible transaction cost plus fees.

Call Fees and Caller Payment

The account which executes the scheduled call is reimbursed 100% of the gas cost + payment for their service. The creator of the Alarm service is also paid the same payment.

The payment value is computed with the formula 1% of GasUsed * BaseGasPrice * GasPriceScalar where:

• GasUsed: is the total gas consumption for the call execution. This includes all of the gas used by the Alarm service to do things like looking up call data, checking for sufficient account balance to pay for the call, paying the caller, etc.
• BaseGasPrice is the gas price that was used by the scheduler when they scheduled the function call.
• GasPriceScalar is a multiplier that ranges from 0 - 2 which is based on the difference between the gas priced used for call execution and the gas price used during call scheduling. This number incentivises the call executor to use as low a gas price as possible.

The GasPriceScalar multiplier

This multiplier is computed with the following formula.

• IF gasPrice > baseGasPrice

baseGasPrice / gasPrice

• IF gasPrice <= baseGasPrice

baseGasPrice / (2 * baseGasPrice - gasPrice)

Where:

• baseGasPrice is the tx.gasprice used when the call was scheduled.
• gasPrice is the tx.gasprice used to execute the call.

At the time of call execution, the baseGasPrice has already been set, so the only value that is variable is the gasPrice which is set by the account executing the transaction. Since the scheduler is the one who ends up paying for the actual gas cost, this multiplier is designed to incentivize the caller using the lowest gas price that can be expected to be reliably picked up and promptly executed by miners.

Here are the values this formula produces for a baseGasPrice of 20 and a gasPrice ranging from 10 - 40 which uses 5000 gas;

gasPrice	multiplier	payout
15	1.20	120
16	1.17	117
17	1.13	113
18	1.09	109
19	1.05	105
20	1.00	100
21	0.95	95
22	0.91	91
23	0.87	87
24	0.83	83
25	0.80	80
26	0.77	77
27	0.74	74
28	0.71	71
29	0.69	69
30	0.67	67
31	0.65	65
32	0.63	63
33	0.61	61
34	0.59	59
35	0.57	57
36	0.56	56
37	0.54	54
38	0.53	53
39	0.51	51
40	0.50	50

You can see from this table that as the gasPrice for the executing transaction increases, the total payout for executing the call decreases. This provides a strong incentive for the entity executing the transaction to use a reasonably low value.

Alternatively, if the gasPrice is set too low (potentially attempting to maximize payout) and the call is not picked up by miners in a reasonable amount of time, then the entity executing the call will not get paid at all. This provides a strong incentive to provide a value high enough to ensure the transaction will be executed.

Overhead

The gas overhead that you can expect to pay for your function call is approximately 150,000 gas.