At least four such job portals, with mobile-friendly websites and apps, have sprung up in the past two years. Openings tend towards lower-skill positions, such as service crew and bartender, which are paid by the hour, unlike on typical portals which offer mainly white-collar jobs in areas such as website design or copywriting.
Mr Mark Koh, who founded such a portal called Temploy last year, believes it is hard for employers to find freelancers without help, especially with mismatched expectations about pay.
The newest app, FastJobs, was launched officially last weekend by Singapore Press Holdings. It has received more than 26,000 job listings and 1,000 applications since the test version was launched in January.
"People are constantly on the move," said senior product manager Ang Yinghui. "We felt it was timely to introduce an app that allows people to search for and apply for non-executive or general jobs in a fuss-free manner."
Job seekers range from students to housewives to retirees. One of them was Ms Edna Loh, 18, who found a weekend job at Cedele over a month ago through an app by Matchimi. "It's convenient for me. I don't have to use a computer or a newspaper to search for jobs," said the final-year opticianry student at the Institute of Technical Education.
Employers using the new portals said they speed up the hiring process by making it easy for on-the-go job seekers to access postings. They also do not require long resumes.
Some employers, such as The Bakery Depot, which owns Cedele, also report shorter waiting times for matches, compared with traditional hiring avenues such as physical advertisements or traineeships.
"These portals have made applying for a job far less intimidating, especially for fresh school leavers," said Mr Lin Ming Kai, human resources executive of Irish pub Muddy Murphy's, referring to LifeOpp and Matchimi. "They also offer smaller organisations an opportunity to reach out to part-time staff at a lower cost than a traditional medium does."
The prices for job posts and applications vary across portals, and some are free of charge. Temploy, for example, charges employers US$2 (S$2.70) for each vacancy and employees US$1 for every job they pick up through the system.
But while most companies see the new portals as a way to diversify their hiring channels in the tight labour market, they have not replaced other forms of hiring. "We are still reliant on internal references by existing employees," said Mr Lin of Muddy Murphy's.
He added that the convenience of the portals cuts both ways - some applicants apply across many postings and get hired for jobs they are not that keen on, resulting in higher turnover.
The number of applicants whom 7-Eleven sees is still higher for traditional forms of hiring, said a spokesman from Dairy Farm, which owns the convenience store chain.
At Capella Singapore, online hiring is done only through the national Jobs Bank and the hotel's website. Human resources director Ervinna Ong said this is done "to keep the hiring process very exclusive".
But the portals could catch on among employees.
"I've tried applying online, responding to newspaper ads and going for walk-in interviews. But many of (the employers) never call back or reply," said Ms Loh, adding that she was contacted by Cedele within a day after applying for the job through Matchimi. "It makes a whole lot of difference if you need a job urgently."