Jualah, الجعا لة, contract form for promise of reward. While in Ijarah the reward is due without success, in Jualah the success must be delivered, while the amount of work is not central. Another difference is that Jualah can be a public offer and whoever delivers first may receive the reward, while in Ijarah the tenant or worker must be known in advance. A Jualah is also different as it is not binding on the worker.
It's applications in finance are among others debt collection and brokerage.