diff --git a/README.md b/README.md
index a1b97910c4..9b350fe47a 100644
--- a/README.md
+++ b/README.md
@@ -254,6 +254,8 @@ Grist can be configured in many ways. Here are the main environment variables it
 
 | Variable                           | Purpose                                                                                                                                                                                                                                                                                                                                                       |
 |------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| ACTION_HISTORY_MAX_ROWS | Maximum number of rows allowed in ActionHistory before pruning (up to a 1.25 grace factor). Defaults to 1000.   |
+| ACTION_HISTORY_MAX_BYTES | Maximum number of rows allowed in ActionHistory before pruning (up to a 1.25 grace factor). Defaults to 1.25Gb.   |
 | ALLOWED_WEBHOOK_DOMAINS            | comma-separated list of permitted domains to use in webhooks (e.g. webhook.site,zapier.com). You can set this to `*` to allow all domains, but if doing so, we recommend using a carefully locked-down proxy (see `GRIST_HTTPS_PROXY`) if you do not entirely trust users. Otherwise services on your internal network may become vulnerable to manipulation.   |
 | APP_DOC_URL                        | doc worker url, set when starting an individual doc worker (other servers will find doc worker urls via redis)                                                                                                                                                                                                                                                |
 | APP_DOC_INTERNAL_URL               | like `APP_DOC_URL` but used by the home server to reach the server using an internal domain name resolution (like in a docker environment). It only makes sense to define this value in the doc worker. Defaults to `APP_DOC_URL`.                                                                                                                                     |
diff --git a/app/server/lib/ActionHistoryImpl.ts b/app/server/lib/ActionHistoryImpl.ts
index 3930d864ec..fdd0ee48d7 100644
--- a/app/server/lib/ActionHistoryImpl.ts
+++ b/app/server/lib/ActionHistoryImpl.ts
@@ -17,9 +17,9 @@ import {ISQLiteDB, ResultRow} from './SQLiteDB';
 // on rows and the maximum total number of bytes in the "body" column.
 // Pruning is done when the history has grown above these limits, to
 // the specified factor.
-const ACTION_HISTORY_MAX_ROWS = 1000;
-const ACTION_HISTORY_MAX_BYTES = 1000 * 1000 * 1000;  // 1 GB.
-const ACTION_HISTORY_GRACE_FACTOR = 1.25;  // allow growth to 1250 rows / 1.25 GB.
+const ACTION_HISTORY_MAX_ROWS = parseInt(process.env.ACTION_HISTORY_MAX_ROWS, 10) || 1000;
+const ACTION_HISTORY_MAX_BYTES = parseInt(process.env.ACTION_HISTORY_MAX_BYTES, 10) || 1000 * 1000 * 1000;  // 1 GB.
+const ACTION_HISTORY_GRACE_FACTOR = 1.25;  // allow growth to 1.25 times the above limits.
 const ACTION_HISTORY_CHECK_PERIOD = 10;    // number of actions between size checks.
 
 /**