We started checking Courier on November 2, 2026, which is 5 days ago. Everything below covers that period, not the full 90 days a longer-tracked service would show.
Email me when Courier reports an incident on its status page, and again when it reports it resolved.
01
The last 24 hours
What happened most recently, on one time axis: our own probe readings by surface, how many people reported a problem, and what Courier's own status page declared. Below it, any public chatter we saw about Courier and the extra probe it triggered.
The last 24 hours on one axis: what our probes read for each surface we check, how many people reported a problem, and what Courier's own status page declared. Three records side by side; none of them changes another.
Our probes, web
Our probes, api (primary)
Unverified user reportsNo reports about Courier in the last 24 hours, which is not evidence that nothing is wrong.
Courier's status pageNo incident declared in the last 24 hours.
24h ago18h ago12h ago6h agonow
Each check cell is the worst reading across every region in that quarter hour: one region that did not answer colours the cell, never an average. An amber cell is a reading that answered, but at three times or more its 7-day median for three checks running: slow is not down, and we say which. A filtered reading stays neutral, because a refused check is not a failed check. Report bars count reports as submitted; we do not check who sent them, and they never change our reading. The status-page lane is Courier's own declaration, shown as they made it.
Third-party chatter, labeled
Public posts from the last hour that mention Courier next to an outage word (“down”, “outage”, “not working”). This is what other people said in public, collected by keyword: not something we measured, and not the user reports above. It never affects the verdict.
No matching public posts in the last hour from the sources we watch.
02
Checks passing by region
Checks passing is the checks that passed, divided by every check we attempted, per region. Not interpolated, not smoothed, and never computed for a region with zero recorded samples.
Region
Checks passing
Probes recorded
US-East
100.00%
469
US-West
99.73%
367
Europe
100.00%
332
Asia-Pacific
100.00%
202
Their declared record
Courier's own incident history, taken from their public status feed. This is their account of what happened, not our check reading.
Queued MessagesMinor incident
Oct 10, 2026, 12:25 AM UTC to Oct 10, 2026, 12:40 AM UTC (15 min)resolved
their latest update (Oct 10, 2026, 12:40 AM UTC): All queued messages have been processed.
Delayed MessagesMinor incident
Oct 9, 2026, 11:15 PM UTC to Oct 9, 2026, 11:52 PM UTC (37 min)resolved
their latest update (Oct 9, 2026, 11:52 PM UTC): This incident has been resolved.
Send Pipeline LatencyMinor incident
Jun 18, 2026, 8:11 PM UTC to Jun 18, 2026, 10:09 PM UTC (1h 57m)resolved
their latest update (Jun 18, 2026, 10:09 PM UTC): Send pipeline has resolved and enqueued messages are now sending properly.
Slack Deliverability IssuesMinor incident
May 27, 2026, 11:06 PM UTC to May 27, 2026, 11:16 PM UTC (10 min)resolved
their latest update (May 27, 2026, 11:16 PM UTC): Please continue to monitor Slack's statuspage for any updates related to message deliverability: https://slack-status.com/
Courier Multi Service OutageMajor outage
Feb 2, 2026, 8:07 PM UTC to Feb 2, 2026, 11:13 PM UTC (3h 7m)postmortem published
their latest update (Feb 12, 2026, 6:10 PM UTC): # RFO: February 2, 2026 — Service Interruption
## Executive Summary
On February 2, 2026, a deployment introduced a configuration change that referenced a file not present in our production build artifacts, causing backend services to become unavailable. API endpoints, automatio…
Observability DegradationMinor incident
Jan 29, 2026, 10:00 AM UTC to Jan 29, 2026, 10:00 AM UTC (0 min)resolved
their latest update (Jan 29, 2026, 10:00 AM UTC): The Courier team identified an issue affecting observability metrics between 21:38 UTC and 22:13 UTC, during which metrics briefly experienced an outage. A fix was released and metrics are stabilized through observability channels. Metrics received during the outage window will n…
Courier Web App PerformanceMinor incident
Jan 14, 2026, 9:47 PM UTC to Jan 15, 2026, 12:56 AM UTC (3h 9m)resolved
their latest update (Jan 15, 2026, 12:56 AM UTC): Fix is out and application is stable
All services impactedMajor outage
Oct 20, 2025, 9:19 AM UTC to Oct 20, 2025, 10:11 AM UTC (52 min)resolved
their latest update (Oct 20, 2025, 10:11 AM UTC): The incident has been resolved
Microsoft Teams Tenant Id ErrorsMinor incident
Oct 17, 2025, 5:33 AM UTC to Oct 17, 2025, 6:01 AM UTC (29 min)resolved
their latest update (Oct 17, 2025, 6:01 AM UTC): Release is in production and Microsoft Teams messages are passing successfully.
Mailgun Message Delivery LatencyAll systems operational
Oct 13, 2025, 4:19 PM UTC to Oct 13, 2025, 4:19 PM UTC (0 min)resolved
their latest update (Oct 13, 2025, 4:19 PM UTC): Courier experienced a slowdown in message delivery with Mailgun providers around 2AM PST. Our monitoring systems caught the spike in the bottleneck, which eventually stabilized. Our infrastructure team is actively monitoring.
Showing the 10 most recent of 50 incidents Courier has declared in the history we hold.
These entries are Courier's own declarations, taken from their public status feed, shown separately from our own check readings. Their page publishes what they choose to publish: an incident missing here means they did not declare one, not that nothing happened, and an incident here is their account, not our measurement. Neither record ever changes the other.
Courier's own status feed works, so its declared incidents are the record and our probe events are not listed or counted. Our check results by region are above, as a reading beside the statement.
Full detail on what a probe does and does not prove is in the methodology page.