Caution: You are viewing documentation for the API's REST interface. Most of our official client libraries use gRPC. See the REST Introduction for details.
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When using the Google Ads API's REST interface, you're working with JSON
representations of the same resources and types defined in the Google Ads API's
.proto descriptor files. The JSON encoding scheme follows the
canonical encoding scheme described in the
JSON Mapping section of the protocol
buffers Language Guide.
In general, all top-level messages to and from
services are single JSON objects.
Most mutate requests contain an operations array that itself contains many
create, update, or delete operations. Similarly, search responses are
JSON objects containing a results array with your query's result set.
Identifiers are transformed from snake_case (in protocol buffers) to
lowerCamelCase in JSON. One notable caveat to this rule is when using
search or searchStream to send Google Ads Query Language
queries. The query language itself uses snake case, regardless of which
interface you're using. However, the results of a query in REST are returned as
normal JSON objects and have their identifiers in lowerCamelCase.
For example, a query to fetch a list of active keywords in an account uses
snake case inside the query itself (ad_group_criterion, not adGroupCriterion):
POST/v21/customers/CUSTOMER_ID/googleAds:searchStreamHTTP/1.1Host:googleads.googleapis.comContent-Type:application/jsonAuthorization:Bearer ACCESS_TOKENdeveloper-token:DEVELOPER_TOKEN{"query":"SELECT ad_group_criterion.keyword.text FROM ad_group_criterion WHERE ad_group_criterion.type = 'KEYWORD' AND ad_group_criterion.status = 'ENABLED'"}
However, the response is a JSON representation of the objects (wrapped in a JSON
array since this request uses searchStream) and uses the camelCase identifier
adGroupCriterion instead:
[{"results":[{"adGroupCriterion":{"resourceName":"customers/1842689525/adGroupCriteria/55771861891~10003060","keyword":{"text":"pay per click"}}},...]}]
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-03 UTC."],[[["\u003cp\u003eThe Google Ads API's REST interface uses JSON to represent resources and types, following the protocol buffers' JSON encoding scheme.\u003c/p\u003e\n"],["\u003cp\u003eTop-level messages in the REST interface are JSON objects, with mutate requests typically containing an \u003ccode\u003eoperations\u003c/code\u003e array and search responses containing a \u003ccode\u003eresults\u003c/code\u003e array.\u003c/p\u003e\n"],["\u003cp\u003eIdentifiers are generally transformed from \u003cem\u003esnake_case\u003c/em\u003e to \u003cem\u003elowerCamelCase\u003c/em\u003e in JSON, with the exception of Google Ads Query Language queries, which use snake case.\u003c/p\u003e\n"],["\u003cp\u003eWhile Google Ads Query Language queries use snake case, the results returned through the REST interface utilize \u003cem\u003elowerCamelCase\u003c/em\u003e for identifiers within the JSON response objects.\u003c/p\u003e\n"]]],[],null,["# JSON Mappings\n\nWhen using the Google Ads API's REST interface, you're working with JSON\nrepresentations of the same resources and types defined in the Google Ads API's\n[.proto descriptor](https://github.com/googleapis/googleapis/tree/master/google/ads/googleads) files. The JSON encoding scheme follows the\ncanonical encoding scheme described in the\n[JSON Mapping](/protocol-buffers/docs/proto3#json) section of the protocol\nbuffers *Language Guide*.\n\nIn general, all top-level messages to and from\n[services](https://github.com/googleapis/googleapis/tree/master/google/ads/googleads/v21/services) are single JSON objects.\nMost mutate requests contain an `operations` array that itself contains many\n`create`, `update`, or `delete` operations. Similarly, `search` responses are\nJSON objects containing a `results` array with your query's result set.\n\nIdentifiers are transformed from *snake_case* (in protocol buffers) to\n*lowerCamelCase* in JSON. One notable caveat to this rule is when using\n`search` or `searchStream` to send [Google Ads Query Language](/google-ads/api/docs/query/overview)\nqueries. The query language itself uses snake case, regardless of which\ninterface you're using. However, the results of a query in REST are returned as\nnormal JSON objects and have their identifiers in lowerCamelCase.\n\nFor example, a query to fetch a list of active keywords in an account uses\nsnake case inside the query itself (`ad_group_criterion`, not `adGroupCriterion`): \n\n```http\nPOST /v21/customers/\u003cvar translate=\"no\"\u003eCUSTOMER_ID\u003c/var\u003e/googleAds:searchStream HTTP/1.1\nHost: googleads.googleapis.com\nContent-Type: application/json\nAuthorization: Bearer \u003cvar translate=\"no\"\u003eACCESS_TOKEN\u003c/var\u003e\ndeveloper-token: DEVELOPER_TOKEN\n\n{\n \"query\": \"SELECT ad_group_criterion.keyword.text\n FROM ad_group_criterion\n WHERE ad_group_criterion.type = 'KEYWORD'\n AND ad_group_criterion.status = 'ENABLED'\"\n}\n```\n\nHowever, the response is a JSON representation of the objects (wrapped in a JSON\narray since this request uses `searchStream`) and uses the camelCase identifier\n`adGroupCriterion` instead: \n\n```javascript\n[\n {\n \"results\": [\n {\n \"adGroupCriterion\": {\n \"resourceName\": \"customers/1842689525/adGroupCriteria/55771861891~10003060\",\n \"keyword\": {\n \"text\": \"pay per click\"\n }\n }\n },\n ...\n ]\n }\n]\n```"]]