Snowflake ID

Short description: Unique identifiers used by Twitter

Template:TwitterSnowflake/gen

Snowflake ID

Other names| Twitter Snowflake

Components of a snowflake identifier in binary

Snowflake IDs, or snowflakes, are a form of unique identifier used in distributed computing. The format was created by Twitter and is used for the IDs of tweets. It is popularly believed that every snowflake has a unique structure, so they took the name "snowflake ID". The format has been adopted by other companies, including Discord and Instagram. The Mastodon social network uses a modified version.

## Contents

* 1 Format
* 1.1 Example
* 2 Usage
* 3 See also
* 4 References
* 5 External links

## Format

Snowflakes are 64 bits in binary. (Only 63 are used to fit in a signed integer.) The first 41 bits are a timestamp, representing milliseconds since the chosen epoch. The next 10 bits represent a machine ID, preventing clashes. Twelve more bits represent a per-machine sequence number, to allow creation of multiple snowflakes in the same millisecond. The final number is generally serialized in decimal.[1]

Snowflakes are sortable by time, because they are based on the time they were created.[1] Additionally, the time a snowflake was created can be calculated from the snowflake. This can be used to get snowflakes (and their associated objects) that were created before or after a particular date.[2]

Fixed header format  Offsets | Octet | 0  | 1  | 2  | 3

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Octet | Bit | 0  | 1  | 2  | 3  | 4  | 5  | 6  | 7  | 8  | 9  | 10  | 11  | 12  | 13  | 14  | 15  | 16  | 17  | 18  | 19  | 20  | 21  | 22  | 23  | 24  | 25  | 26  | 27  | 28  | 29  | 30  | 31
0  | 0  | Timestamp
4  | 32  |  | Machine ID | Machine Sequence Number

### Example

A tweet produced by @Wikipedia in June 2022[3] has the snowflake ID 1541815603606036480. The number may be converted to binary as 00 0001 0101 0110 0101 1010 0001 0001 1111 0110 0010 00|01 0111 1010|0000 0000 0000, with pipe symbols denoting the three parts of the ID.

* The first 41 (+ 1 top zero bit) bits convert to decimal as 367597485448. Add the value to the Twitter Epoch of 1288834974657 (in Unix time milliseconds),[4] the Unix time of the tweet is therefore 1656432460.105: June 28, 2022 16:07:40.105 UTC.
* The middle 10 bits 01 0111 1010 are the machine ID.
* The last 12 bits decode to all zero, meaning this tweet is the first tweet processed by the machine at the given millisecond.

## Usage

The format was first announced by Twitter in June 2010.[5] Due to implementation challenges, they waited until later in the year to roll out the update.[6]

* Twitter uses snowflake IDs for tweets, direct messages, users, lists, and all other objects available over the API.[7]
* Discord also uses snowflakes, with their epoch set to the first second of the year 2015.[2]
* Instagram uses a modified version of the format, with 41 bits for a timestamp, 13 bits for a shard ID, and 10 bits for a sequence number.[8]
* Mastodon's modified format has 48 bits for a millisecond-level timestamp, as it uses the UNIX epoch. The remaining 16 bits are for sequence data.[9]

## See also

* Universally unique identifier

## References

1. ↑ 1.0 1.1 "twitter-archive/snowflake at b3f6a3c6ca". October 1, 2012. https://github.com/twitter-archive/snowflake/tree/b3f6a3c6ca8e1b6847baa6ff42bf72201e2c2231.
2. ↑ 2.0 2.1 "API Reference". Discord. https://discord.com/developers/docs/reference#snowflakes.
3. ↑ @Wikipedia. "53 years ago today, members of the LGBTQI+ community began protesting in New York City in response to a police raid of the Stonewall Inn, a popular gay bar. The riots were a transformative event in the 20th century fight for LGBTQI+ rights in the US. (1/2)". https://twitter.com/Wikipedia/status/1541815603606036480. Missing or empty `|date=` (help)
4. ↑ "2019-08-03: TweetedAt: Finding Tweet Timestamps for Pre and Post Snowflake Tweet IDs". https://ws-dl.blogspot.com/2019/08/2019-08-03-tweetedat-finding-tweet.html.
5. ↑ King, Ryan (June 1, 2010). "Announcing Snowflake". Twitter. https://blog.twitter.com/engineering/en_us/a/2010/announcing-snowflake.html.
6. ↑ Siegler, MG (October 12, 2010). "Tweet IDs About To Get Jumbled In A Blizzard As Snowflake Is Set To Roll Live". https://techcrunch.com/2010/10/12/twitter-snowflake/.
7. ↑ "Twitter IDs". Twitter. https://developer.twitter.com/en/docs/twitter-ids.
8. ↑ "Sharding & IDs at Instagram" (in en). May 2, 2016. https://instagram-engineering.com/sharding-ids-at-instagram-1cf5a71e5a5c.
9. ↑ Source Code  mastodon/mastodon, Mastodon, 2022-11-11, https://github.com/mastodon/mastodon/blob/5e796dc6f85b37c8378fe01cfd8ac23222c89eea/lib/mastodon/snowflake.rb, retrieved 2022-11-11

## External links

* on GitHub

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