[5] The OV-chipkaart works in two ways: either as a stored-value card which is used to travel on pre-loaded credit (Dutch: reizen op saldo); or as a means of storing so-called "travel products" (Dutch: reisproducten) such as single or return rail tickets, day passes, seasonal tickets and discount plans.

Card readers are placed at station entrances (metro and train) and on board vehicles (bus, tram, and light rail).

[7] But this is exceptional: for example, failing to check out and then in again when changing between trams will charge the user the whole deposit (currently €4) rather than the actual fare for their journey (further explained below).

In the event of a machine failure (e.g. if all card validators are out of service), or if the user can prove the real journey, such as checking into a local bus after leaving the train, the excess fee paid can be claimed back from the transport operator.

When checking in at a ticket barrier, the gates are opened after a deposit has been collected from the stored value on the passenger's OV-chipkaart or when an appropriate travel product has been acknowledged.

If no travel product (such as a single or return journey) has been loaded or no deposit can be collected because of insufficient funds on the card, the ticket barriers will refuse to open and access to the station is denied.

During a rail or metro journey, conductors or ticket inspectors use mobile card readers to verify whether passengers have properly checked in with their OV-chipkaart before boarding.

On most buses and trams in the Netherlands, passengers are required to board at a door near the driver or conductor, which allows for the check-in process to be monitored.

The screens on card validators and ticket barriers will display the amount deducted from the stored credit and remaining balance when a passenger checks out.

The anonymous and personal versions of the card used MIFARE Classic 4K chips, protected from unlawful access by security keys known only to the vendor.

The disposable version of the OV-chipkaart (Dutch: eenmalige chipkaart or wegwerpkaart) is made of thick paper, suitable for short use.

Since July 2014, international rail tickets are also issued in the form of disposable cards when purchased at a Dutch railway station, but without a surcharge.

Anonymous cards can also be used to store a limited number of non-personalized travel products, such as one-hour or day passes for specific public transport systems.

The personal OV-chipkaart is intended for use by residents of the Netherlands, as a Dutch permanent address and bank account must be provided when applying for a card.

The process, which started in 2005 and was finally completed in 2014, has been plagued with cost-overruns, delays because of technical difficulties, planning and co-ordination problems, and resistance from consumer groups and politicians because of concerns over the safety and user-friendliness of the system, resulting in waning public support.

[17] Passengers travelling on pre-loaded credit must always check out at the end of their journey in order for the deposit, which was deducted upon check-in, to be reimbursed to their OV-chipkaart.

In addition, the reimbursement procedure requires submitting a paper or online form with the transport operator concerned[19] which some passenger consider too cumbersome in relation to the amount lost.

An investigation commissioned by passenger associations showed that the check-out problem results in an estimated profit of nearly €23 million a year for public transport operators.

Transport operators have questioned the validity of the numbers, claiming the total amount is not more than a few million euros and that they are willing to reimburse lost deposits.

The check-out problem was one of the reasons the Rotterdam public transport operator RET began an experiment in March 2014 with travelling-on-account, whereby OV-chipkaart users do not need to pre-load credit or maintain a minimum balance for the deposit to be deducted, but instead receive a bill for their journeys at the end of the month.

By doing so, the Data Protection Authority concluded, "the risk of the unlawful monitoring of individual people’s travel behaviour will be limited considerably.

"[23] In a lawsuit brought by a group of students against main rail operator NS in 2012, the district court in Utrecht ruled that NS did not act unlawfully by requiring students to check in and check out when travelling on their government-sponsored public transport pass, which could only by used when loaded on a personal OV-chipkaart.

[25] Independent technological reviews and several hacking attempts continue to draw attention to the security and safety of the OV-chipkaart system.

In 2007, students at the University of Amsterdam discovered several vulnerabilities in the disposable, single-use chipcard technology used by municipal transport operator GVB, which allowed for the cards to be reprogrammed for unlimited use.

[26] German hackers reported later that year that the security code of the MIFARE Classic chips used for anonymous and personal OV-chipkaarts could easily be hacked with technology available for less than 100 euros.

A counter expertise review by the Information Security Group at Royal Holloway, University of London, commissioned by the Dutch Ministry of Transport, Public Works and Water Management, concluded that the TNO report underestimated (later acknowledged by TNO itself) the risk of more systematic hacking attempts in the future and the ease with which these could be carried out, as well as the loss of confidence in the system this may cause with passengers.

[28] When the Royal Holloway review was presented to the Dutch House of Representatives in April 2008, co-ordinating state secretary Huizinga expressed doubt as to whether the planning for the national roll-out of the OV-chipkaart and subsequent phasing out of the traditional paper ticketing systems, which was set to be completed by January 1, 2009, was still realistic.

Despite new publications that year of successful hacking attempts as well as fraud schemes,[30] transport minister Schultz concluded that the card was safe enough to fully replace the thirty-year-old strippenkaart system.