While there is generally no issue with using an old-fashioned conventional lock and key (or combination locks that are entirely mechanical), there is of course the issue of transporting the key in a permissible way on Shabbat.

Moreover, with advancements of technology, locks and keys have become more sophisticated, posing a host of potential problems. We will discuss some of the issues together with possible solutions for using these doors and locks on Shabbat.

Carrying a Key on Shabbat

One of the 39 melachot (categories of work) prohibited on Shabbat is hotza’ah—carrying from a private to a public domain, or carrying even four cubits within a public area. Clothing, jewellery or fashion accessories, however, are not considered “carrying,” since they’re part of what you wear.

That exception led to some creative Shabbat solutions over the generations. After all, people needed to lock their doors—but how could they take their keys outside without an eruv?

Simply hanging a key from your belt or bracelet doesn’t help; the key isn’t serving any function, so it’s still considered carrying. But if the key becomes part of the garment itself—something that actually holds or fastens it—then it’s viewed as part of your clothing and you can wear it outside on Shabbat.1

Creative Solutions

One old-fashioned fix was to make the key the tongue of the belt buckle—the piece that goes through the hole. That way, the belt couldn’t fasten without the key.2 Others turned it into a piece of jewelry, like a decorative silver key, which served as an ornament such as a brooch or a tie clip.3

In recent years, a more practical option has become popular: the “Shabbos belt.” It’s made from elastic or string, with each end securely attached to opposite sides of the bow of the key, so the key itself keeps it closed.4

You can even attach multiple keys this way using small clips or carabiners.5

Wearing It Properly

To count as part of your clothing, the Shabbat belt must be worn in the normal way people wear belts. If you’re already wearing a regular belt or have your shirt tucked in, put the Shabbat belt on a different layer of your clothing.6

Another option: unbutton part of your shirt and use the Shabbat belt to keep it closed—again making the key serve a real purpose.7

Unlocking the Door

What about when you get home and actually need to use the key? If you are in the public domain and the door goes into a private domain, you need to be careful not to transport (“carry”) the key from one domain to another.

At what point does this happen? If the keyhole goes completely through the door (such an old-fashioned mortise lock), that lock is considered part of a reshut hayachid (private domain). In that case, if you’re standing in a public area, you must unlock the door while still wearing the belt.8

But most modern locks don’t go all the way through, so inserting the key into the keyhole is not an issue. But transporting it through the open doorway is. So while you can remove the belt with the key from your waist to unlock the door, be sure to remove the key and put it back on your waist before pushing the door open and walking through.

Keys in Shared Areas

If you hid a key before Shabbat in a shared hallway or lobby where no eruv chatzeirot was made, it may be carried within that shared area.9 However, you may not bring the key into your apartment, since that would be transferring between domains. The key should also be removed from the keyhole before opening the door.

Automatic Doors

Many buildings and facilities have doors that open automatically when triggered by a motion or proximity sensor. Before Shabbat, try to find out if there’s a regular door (such as a side or service entrance) that can be used instead.

If using the automatic door is unavoidable, wait for a non-Jew to trigger the sensor and then follow them through the open doorway—taking care not to activate the sensor yourself (nor bump into the person ahead).10

Electronic Keys

Doors that open with electronic key cards, fobs, or keypads may not be used on Shabbat, as doing so activates electrical circuits. These devices are also considered muktzeh and should not be handled.

Where possible, arrange before Shabbat to use a door with a standard key, or to have staff open the door for you as needed.11

If security isn’t a concern, you can use simple mechanical workarounds:

  • Insert a small object (like a folded paper) into the latch hole, tape the latch down, or weigh the handle from the inside so the door doesn’t fully lock.
  • Alternatively, attach a long string to the inside handle and feed it under the door so that it protrudes slightly into the hallway. You can then pull the string to open the door from outside.

Always test these methods before Shabbat to ensure they work smoothly and discreetly.

Smart Locks

Smart locks present new Shabbat challenges. Some models automatically lock after a set time, creating an electrical impulse when triggered, and are therefore problematic on Shabbat.

Even when the auto-lock is off, most smart locks record every use, sending signals to an app each time the door opens or closes. This raises the question: does that background logging violate Shabbat?

If the homeowner benefits from this recordkeeping, it’s a problem even though it is inevitable (the technical term for this is Pesik Reisha DeNeicha Lei), even if only rabbinically prohibited. However, since most people don’t care about individual log entries, some authorities view it as a non-beneficial result, which allows for leniency in times of need.12

For the homeowner, the system’s ongoing operation may still be seen as beneficial, since it was installed intentionally. For a guest, however, who gains nothing from the log, entering or leaving would be permitted.13

Practically, you should ideally disable smart locks before Shabbat. If that wasn’t done, then at least the non-homeowner may rely on lenient opinions to enter or exit the home (there are some rabbis who, in a time of need, are lenient regarding homeowners who have this device installed as well).14

(It needs to be emphasized that this only applies to smart locks. Broader smart-home systems that activate lights, climate control, or other similar devices must be disabled before Shabbat, and if left on, may not be operated by a Jew.)

Opening a Door Near a Candle

When a candle is burning, one should not open a nearby door (or window), since the wind might blow out the flame. Even if the wind seems weak, it could strengthen just as the door is opened, and the act of opening it could extinguish the flame.15

If the candle is far from the door (or positioned so that even a strong wind couldn’t reach it and definitely put it out), the door may be opened—even if the flame may flicker.16

Additionally, If the wind begins to blow after the candles are lit, the door may be closed to protect the flame, since this only prevents the wind from reaching it.17

Trapping Pets Inside

Trapping, defined as any act which restricts the freedom of an animal, is forbidden on Shabbat. Generally this does not apply to most household pets, since the prohibition of “trapping” only concerns animals that might escape and are difficult to catch. Domesticated animals that usually stay near their owners are considered already “trapped” by nature or training.18

However, if your pet tends to run away, you may not close a door (or window) through which it could realistically escape.19 To avoid this issue, make sure to secure your pet before opening or closing the door, or stand in the doorway to block the exit so there is no chance for the animal to slip out and your subsequent closing of the door is thus not considered “trapping.”

For more on the laws of Shabbat and pet ownership, see How does Shabbat observance affect pet owners?