You can use the **[Purge History API](https://github.com/matrix-org/synapse/blob/master/docs/admin_api/purge_history_api.rst)** to delete old messages on a per-room basis. **This is destructive** (especially for non-federated rooms), because it means **people will no longer have access to history past a certain point**.
You can use the **[Purge History API](https://github.com/matrix-org/synapse/blob/master/docs/admin_api/purge_history_api.md)** to delete old messages on a per-room basis. **This is destructive** (especially for non-federated rooms), because it means **people will no longer have access to history past a certain point**.
To make use of this API, **you'll need an admin access token** first. You can find your access token in the setting of some clients (like Element).
To make use of this API, **you'll need an admin access token** first. You can find your access token in the setting of some clients (like Element).
Alternatively, you can log in and obtain a new access token like this:
Alternatively, you can log in and obtain a new access token like this:
Synapse's Admin API is not exposed to the internet by default. To expose it you will need to add `matrix_nginx_proxy_proxy_matrix_client_api_forwarded_location_synapse_admin_api_enabled: true` to your `vars.yml` file.
Synapse's Admin API is not exposed to the internet by default. To expose it you will need to add `matrix_nginx_proxy_proxy_matrix_client_api_forwarded_location_synapse_admin_api_enabled: true` to your `vars.yml` file.
Follow the [Purge History API](https://github.com/matrix-org/synapse/blob/master/docs/admin_api/purge_history_api.rst) documentation page for the actual purging instructions.
Follow the [Purge History API](https://github.com/matrix-org/synapse/blob/master/docs/admin_api/purge_history_api.md) documentation page for the actual purging instructions.
After deleting data, you may wish to run a [`FULL` Postgres `VACUUM`](./maintenance-postgres.md#vacuuming-postgresql).
After deleting data, you may wish to run a [`FULL` Postgres `VACUUM`](./maintenance-postgres.md#vacuuming-postgresql).