# Stats scrapy-zyte-api exposes the following [Scrapy stats](https://docs.scrapy.org/en/latest/topics/stats.md#topics-stats) with the `scrapy-zyte-api` prefix: `scrapy-zyte-api/429` : Number of Zyte API responses with status code 429. See [Zyte API rate limits](https://docs.zyte.com/zyte-api/usage/rate-limit.md#zapi-rate-limit). `scrapy-zyte-api/attempts` : Total number of Zyte API request attempts, including retries. `scrapy-zyte-api/auto_fields/{cls}` : Space-separated list of auto fields for the page object class `{cls}`, or the string `(all fields)` if all fields are auto fields.
Only set when [`ZYTE_API_AUTO_FIELD_STATS`](settings.md#std-setting-ZYTE_API_AUTO_FIELD_STATS) is `True`. `scrapy-zyte-api/error_ratio` : Ratio of [unsuccessful responses](https://docs.zyte.com/zyte-api/usage/errors.md#zapi-unsuccessful-responses) to `scrapy-zyte-api/processed`. `scrapy-zyte-api/error_types/{error_type}` : Number of [unsuccessful responses](https://docs.zyte.com/zyte-api/usage/errors.md#zapi-unsuccessful-responses) for each error type, where `{error_type}` is the `type` field from the Zyte API error response. `scrapy-zyte-api/errors` : Total number of [unsuccessful responses](https://docs.zyte.com/zyte-api/usage/errors.md#zapi-unsuccessful-responses). `scrapy-zyte-api/exception_types/{exception_type}` : Number of exceptions of type `{exception_type}` raised during Zyte API request processing. `scrapy-zyte-api/fatal_errors` : Number of unrecoverable Zyte API errors, such as requests with invalid parameters. `scrapy-zyte-api/mean_connection_seconds` : Mean connection time in seconds across all Zyte API requests. `scrapy-zyte-api/mean_response_seconds` : Mean total time in seconds from sending a Zyte API request to receiving the full response. `scrapy-zyte-api/processed` : Total number of Zyte API request attempts with a definitive outcome (either success or error). `scrapy-zyte-api/request_args/{arg}` : Number of Zyte API requests that used parameter `{arg}`.
For `experimental` sub-parameters, the stat name uses dot notation: `scrapy-zyte-api/request_args/experimental.{subarg}`. > ##### NOTE > > [Session](../usage/session.md#session) stats (`scrapy-zyte-api/sessions/…`) are > aggregated across all session pools by default. Set > [`ZYTE_API_SESSION_STATS_PER_POOL`](settings.md#std-setting-ZYTE_API_SESSION_STATS_PER_POOL) to `True` to enable per-pool > stats. The `pools/{pool}/` fragment in the stat names below is only > present when per-pool stats are enabled. `scrapy-zyte-api/sessions/pools/{pool}/init/check-error` : Number of times that a session for pool `{pool}` triggered an unexpected exception during its session validation check right after initialization.
It is most likely the result of a bad implementation of [`SessionConfig.check`](../usage/session.md#scrapy_zyte_api.SessionConfig.check); the logs should contain an error message with a traceback for such errors. `scrapy-zyte-api/sessions/pools/{pool}/init/check-failed` : Number of times that a session from pool `{pool}` failed its session validation check right after initialization. `scrapy-zyte-api/sessions/pools/{pool}/init/check-passed` : Number of times that a session from pool `{pool}` passed its session validation check right after initialization. `scrapy-zyte-api/sessions/pools/{pool}/init/failed` : Number of times that initializing a session for pool `{pool}` resulted in an [unsuccessful response](https://docs.zyte.com/zyte-api/usage/errors.md#zapi-unsuccessful-responses). `scrapy-zyte-api/sessions/pools/{pool}/init/param-error` : Number of times that initializing a session for pool `{pool}` triggered an unexpected exception when obtaining the Zyte API parameters for session initialization.
It is most likely the result of a bad implementation of [`SessionConfig.params`](../usage/session.md#scrapy_zyte_api.SessionConfig.params); the logs should contain an error message with a traceback for such errors. `scrapy-zyte-api/sessions/pools/{pool}/use/check-error` : Number of times that a response that used a session from pool `{pool}` triggered an unexpected exception during its session validation check.
It is most likely the result of a bad implementation of [`SessionConfig.check`](../usage/session.md#scrapy_zyte_api.SessionConfig.check); the logs should contain an error message with a traceback for such errors. `scrapy-zyte-api/sessions/pools/{pool}/use/check-failed` : Number of times that a response that used a session from pool `{pool}` failed its session validation check. `scrapy-zyte-api/sessions/pools/{pool}/use/check-passed` : Number of times that a response that used a session from pool `{pool}` passed its session validation check. `scrapy-zyte-api/sessions/pools/{pool}/use/expired` : Number of times that a session from pool `{pool}` expired. `scrapy-zyte-api/sessions/pools/{pool}/use/failed` : Number of times that a request that used a session from pool `{pool}` got an [unsuccessful response](https://docs.zyte.com/zyte-api/usage/errors.md#zapi-unsuccessful-responses). `scrapy-zyte-api/sessions/use/disabled` : Number of processed requests for which session management was disabled. `scrapy-zyte-api/status_codes/{status_code}` : Number of Zyte API responses with HTTP status code `{status_code}`, e.g. `429` for [rate limiting](https://docs.zyte.com/zyte-api/usage/rate-limit.md#zapi-rate-limit) or `520` for [temporary download errors](https://docs.zyte.com/zyte-api/usage/errors.md#zapi-temporary-download-errors).
> ##### NOTE > > The actual status code received from the target website, i.e. > the [statusCode](https://docs.zyte.com/zyte-api/usage/reference.md#operation/extract/response/200/statusCode) response field of a [Zyte API > successful response](https://docs.zyte.com/zyte-api/usage/errors.md#zapi-successful-responses), is accounted for in > the `downloader/response_status_count/{status_code}` stat, as with > any other Scrapy response. `scrapy-zyte-api/success` : Number of [successful Zyte API responses](https://docs.zyte.com/zyte-api/usage/errors.md#zapi-successful-responses). `scrapy-zyte-api/success_ratio` : Ratio of [successful responses](https://docs.zyte.com/zyte-api/usage/errors.md#zapi-successful-responses) to `scrapy-zyte-api/processed`. `scrapy-zyte-api/throttle_ratio` : Ratio of [rate-limited responses](https://docs.zyte.com/zyte-api/usage/rate-limit.md#zapi-rate-limit) to `scrapy-zyte-api/processed`.