Limits

Every limit that can change what you receive is documented here. An undocumented limit is indistinguishable from a bug, and a customer who hits one with no way to find out will reasonably conclude the product is broken.

Slots and cadence

There are three ceilings here and they bound each other rather than multiplying. Read the row across before you read any single number: on Growth, 30, 25 and 3 are three different quantities, not three descriptions of the same allowance.

A monitor slot is one monitor row, whatever it watches. A distinct subreddit is one named subreddit counted once across every monitor on the account, however many monitors name it. An all-of-Reddit watch is a monitor with no subreddit named, matching a keyword against every new post on Reddit.

Each is metered on its own because each costs something different. One monitor may name up to 50 subreddits, so without the second column a Starter account could stand up 400 poll streams from 15 monitors, and each distinct subreddit is its own poll against a shared budget. All-of-Reddit watches are the opposite shape: every one of them rides the same single r/all/new stream, so the hundredth costs no more Reddit calls than the first. What they do cost is delivery volume and matching work, which is why they are capped rather than unlimited. A monitor row on its own costs nothing, which is why the slot count is the loosest of the three.

Exceeding any of them returns 402, naming which one: monitor_slots_exhausted, distinct_subreddit_limit_reached, or sitewide_slots_exhausted. Every one of these caps, and how many monitors and distinct subreddits you are currently using, is reported on /reddit/monitor/list, so you never have to guess where you stand.

What you get for free

Every account gets one watch for free, with no card. It covers new posts matching one keyword anywhere on Reddit, checked about every 60 seconds, sent to your webhook, Slack or Discord, up to 10,000 alerts a day.

The free watch cannot name a subreddit. Watching a named subreddit is on the paid plans, because each named subreddit is its own poll, while every all-of-Reddit watch shares a single one. Asking for a subreddit on the free watch returns 402 and names the upgrade.

Comment matches, checks faster than 60 seconds, and a second watch are also on the paid plans.

A slot is a monitor, not a match and not a delivery. One monitor may name up to 50 subreddits; what bounds how many different subreddits you may watch is the distinct-subreddit column above, counted across the whole account, and what bounds how many of your monitors may skip the subreddit entirely is the all-of-Reddit column beside it. Creating a monitor beyond any of the three ceilings returns 402, and the error names which one.

Detection times are typical, not guaranteed. Reddit has no push stream, so everything here is poll-bound.

Per-monitor daily delivery ceiling

There are no per-match charges and no API credits spent, so match volume never moves your bill. There is a per-monitor daily delivery ceiling, it is enforced, and here is the number:

The count is per monitor, not per account, and it resets at midnight UTC. It exists for a reason worth being honest about.

A monitor on a very high-volume subreddit with kind: "both" and no filter can match tens of thousands of items a day. Delivering all of them means a sustained flood of outbound requests, from us, with our name on them, at your server. That is a denial of service we would be committing on your behalf.

When the ceiling engages:

• Deliveries stop for that monitor for the rest of the day.
• Suppressed alerts are recorded as delivery rows with status suppressed, counted into suppressed_24h on /reddit/monitor/health, and readable individually on /reddit/monitor/deliveries?status=suppressed with the same post content a delivered alert carries.
• The counter resets daily.

A suppressed alert is visible as suppressed, which is the difference between a documented limit and a bug.

suppressed_24h counts more than the ceiling. The freshness gate also withholds matches, and those are recorded the same way, with payload.suppressed.reason = stale_item instead of delivery_ceiling. Read suppressed_breakdown on /reddit/monitor/health to split them, and read ceiling_reached rather than suppressed_24h > 0 to answer "am I over my limit" -- a stale withhold never sets that flag, because no limit rejected it. See Endpoints.

suppressed_24h is a floor, not a total. We store up to 500 ceiling suppression records per monitor per UTC day. The stored rows are a sample of what was held back, not a ledger of every one: a monitor matching many times over its ceiling would otherwise write hundreds of thousands of rows a day for alerts it is not sending. Past the cap, suppression still stops deliveries and still resets at midnight UTC, it just stops adding rows. The row that reaches the cap says so, in its payload, at payload.suppressed.record_cap_reached. So a suppressed_24h in the hundreds means "at least this many, and the real number may be far larger", never "this is the total". Treat any monitor whose suppressed_breakdown.ceiling is above zero as one whose ceiling is doing real work. A monitor with suppressed_24h above zero and ceiling at zero has not touched its limit at all: those are freshness withholds, and raising the ceiling would not change them.

If you are hitting it, the fix is a narrower filter rather than a bigger plan. The ceiling is per monitor, not per plan.

For scale: the busiest monitor we have ever run in production peaked at 2,091 deliveries in a day, so the lowest number in the table above is roughly 4.8x that. That figure is context for sizing your own workload, not a suggestion that the ceiling is soft. It is checked on every delivery and a monitor that reaches it stops sending until the next UTC day.

Retention

Polled items are retained for 14 days by default and never more than 30. The window exists to deduplicate the poll stream, not to build an archive.

This is not a product limitation we would remove if asked. Reddit's terms require deleting data not needed for the approved use, and monitoring's approved use is detection, which needs days rather than years. If you need history, keep what we deliver on your side, or use the per-call API.

Rate limits on management calls

Management endpoints are rate limited in fixed 60-second windows, shared across all API keys on your account. Exceeding it returns 429. Delivery is unaffected: a management limit never delays an alert.

What happens when a payment fails

• A failed payment starts a 3-day grace period. Nothing changes during it: monitors keep running while you fix the card. That is the entire point.
• After grace, monitors pause. They are never deleted.
• Cancelling pauses at period end: not immediately. You keep what you paid for.
• Downgrading keeps your newest monitors active up to the new ceiling and pauses the rest. You are told which ones stopped.

Nothing in this system deletes a monitor for a billing reason. A monitor holds a filter you wrote by hand; pausing is reversible the moment you pay, and deleting is not reversible at all.

Concurrency

Deliveries to a single target are ordered. If your endpoint is slow, deliveries queue rather than fanning out and arriving out of order.

If the delivery queue is saturated, callers receive a 503 with Retry-After rather than hanging. A request that waits forever is worse than one that fails quickly, because it ties up a connection on both ends and tells you nothing.