Realtime Database Limits

The following are restrictions on data storage and operations inFirebase Realtime Database. To scale beyond any of these limits,use multiple databases.

Global

OperationLimitDescription
Simultaneous connections200,000*

A simultaneous connection is equivalent to one mobile device, browser tab,or server app connected to the database.

This isn't the same as the total number of users of your app, because yourusers don't all connect at once. For example, apps with 10 million monthlyactive users usually have fewer than 200,000 simultaneous connections. Your maxsimultaneous connections depends on your total user count and the average timeusers spend in your app.

However, if you need to scale beyond this limit, tryusing multiple databases.

*The Spark plan limit on simultaneous connections is 100.

Simultaneous responses sent from a single database.~100,000/secondResponses include simultaneous broadcast and read operations sent by theserver from a single database at a given time. The limit refers to the datapackets that represent each individual read or broadcast operation, includingpush notifications, sent from the database. This guidance is for sustained load,but the database can handle occasional higher bursts.
Number of Cloud Functions triggered by a single write1000; or, forCloud Functions v2, 500 per regionWhile there isn't a limit to how many read or write operations you cantrigger from a single function, a single database write operation can onlytrigger 1000 functions, or 500 functions per region forCloud Functions v2.

Cloud Functions can only be triggered by write operations, and each function can also trigger more write operations that trigger more functions (each with their own 1000-function or 500-per-region limit).

Size of a single event triggered by a write1 MBThe size of an event consists of the following values:
  1. The existing data at the write location.
  2. The update value, or the delta in data necessary to write the new data to the location.
Write operations larger than 1MB succeed on the database, but they don't trigger a function invocation.
Data transfer toCloud Functions10MB/sec sustainedThe rate of event data that can be forwarded toCloud Functions.
Disable strict enforcement for trigger limits

Strict validation is enabled by default for write operations that trigger events. Any write operations that trigger more than 1000 Cloud Functions or a single event greater than 1 MB in size will fail and return an error reporting the limit that was hit. This might mean that some Cloud Functions aren't triggered at all if they fail the pre-validation.

If you're performing a larger write operation (for example, deleting your entire database), you might want to disable this validation, as the errors themselves might block the operation.

To turn offstrictTriggerValidation, follow these steps:

  1. Get your Database secret from theService accounts tab of yourProject settings in theFirebase console.
  2. Run the following CURL request from your command line:
    3. curl -X PUT -d "false" https://<namespace>.firebaseio.com/.settings/strictTriggerValidation/.json?auth\=<SECRET>

Data tree

PropertyLimitDescription
Maximum depth of child nodes32Each path in your data tree must be less than 32 levels deep.
Length of a key768 BytesKeys are UTF-8 encoded and can't contain new lines or any of the followingcharacters:
. $ # [ ] / or any ASCII control characters (0x00 - 0x1F and 0x7F)
Maximum size of a string10 MBData is UTF-8 encoded.

Reads

DescriptionLimitNotes
Size of a single response served by the database256 MBThe size of data downloaded from the database at a single location should beless than 256 MB for each read operation.

To perform a read operation at a larger location, try one of the followingoptions:

Total nodes in a path with listeners or queries on it75 million*You can't listen to or query paths with more than 75 million nodes,cumulative. However, you can still listen to or query child nodes. Try drillingdown deeper into the path or creating separate listeners or queries for morespecific portions of the path.

*You can't view paths with more than 30,000 total nodes from the dataviewer in theFirebase console.

Length of time a single query can run15 minutes*A single query can run for up to 15 minutes before failing.

*A single query performed in theFirebase console can only run for upto 5 seconds before failing.

Writes

DescriptionLimitNotes
Write rate1,000 writes/secondThe limit on write operations per second on a single database. While not a hard limit, if you sustain more than 1,000 writes per second, your write activity may be rate-limited.
Size of a single write request to the database256 MB from the REST API; 16 MB from the SDKs.The total data in each write operation should be less than 256 MB.Multi-path updates are subject to the same size limitation.
Bytes written64 MB/minuteThe total bytes written through simultaneous write operations on thedatabase at any given time.

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Last updated 2025-07-10 UTC.