Place Autocomplete uses session tokens to group the query and selection
phases of a user autocomplete search into a discrete session for billing
purposes. The session begins when the user starts typing a query, and concludes
when they select a place and a call to Place Details is made. Each session can
have multiple autocomplete queries, followed by one place selection. The API
key(s) used for each request within a session must belong to the same
Google Cloud console project. Once a session has concluded, the token is no longer
valid; your app must generate a fresh token for each session. If the
sessiontoken parameter is omitted, or if you reuse a session
token, the session is charged as if no session token was provided (each request
is billed separately).
We recommend the following guidelines:
- Use session tokens for all autocomplete sessions.
- Generate a fresh token for each session.
- Ensure that the API key(s) used for all Place Autocomplete and Place Details requests within a session belong to the same Google Cloud console project.
- Be sure to pass a unique session token for each new session. Using the same token for more than one session will result in each request being billed individually.
You can optionally omit the autocomplete session token from a request. If the session token is omitted, each request is billed separately, triggering the Autocomplete - Per Request SKU. If you reuse a session token, the session is considered invalid and the requests are charged as if no session token was provided.
Example
As the user types a query, an autocomplete request is called every few keystrokes (not per-character), and a list of possible results is returned. When the user makes a selection from the result list, the selection counts as a request, and all of the requests made during the search are bundled and counted as a single request. If the user selects a place, the search query is available at no charge, and only the Place data request is charged. If the user does not make a selection within a few minutes of the beginning of the session, only the search query is charged.
Let's examine this flow of events from the perspective of an app.
- A user begins typing a query to search for "Paris, France".
- Upon detecting user input, the app creates a new session token, "Token A".
- As the user types, the API makes an autocomplete request every few
characters, displaying a new list of potential results for each:
"P"
"Par"
"Paris,"
"Paris, Fr"
- When the user makes a selection:
- All requests resulting from the query are grouped and added to the session represented by "Token A", as a single request.
- The user's selection is counted as a Place Detail request, and added to the session represented by "Token A".
- The session is concluded, and the app discards "Token A".
For more information about how Autocomplete requests are billed, see Usage and Billing.
Create session tokens
You can create session tokens using whichever programmatic mechanism you prefer. We recommend using a version 4 UUID for session tokens.