diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7459ebd..0d290d2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
### Added
+- Failed job trend chart — "Failures — last 12 hours" sparkline added to the Solid Queue dashboard card below the throughput sparkline; bars render in the danger color to make failure spikes immediately visible
- Error frequency report — `GET /failed_jobs/errors` groups all failed jobs by exception class and message prefix, showing count and an expandable sample backtrace per group; links through to a filtered failed jobs list via `?error_class=`; the failed jobs index gains an "Error Summary" button and shows an active-filter breadcrumb with a clear link
## [1.0.0] - 2026-05-27
diff --git a/app/assets/stylesheets/solid_stack_web/_07_dashboard.css b/app/assets/stylesheets/solid_stack_web/_07_dashboard.css
index f37fa29..bc24208 100644
--- a/app/assets/stylesheets/solid_stack_web/_07_dashboard.css
+++ b/app/assets/stylesheets/solid_stack_web/_07_dashboard.css
@@ -86,6 +86,10 @@ a.sqw-inline-stat:hover { opacity: 0.7; text-decoration: none; }
color: var(--primary);
}
+.sqw-sparkline-wrap--failures {
+ color: var(--danger);
+}
+
.sqw-sparkline-label {
display: block;
font-size: 10px;
diff --git a/app/controllers/solid_stack_web/dashboard_controller.rb b/app/controllers/solid_stack_web/dashboard_controller.rb
index e91fc62..90e1947 100644
--- a/app/controllers/solid_stack_web/dashboard_controller.rb
+++ b/app/controllers/solid_stack_web/dashboard_controller.rb
@@ -5,6 +5,7 @@ def index
@cache_stats = CacheStats.new.to_h
@cable_stats = CableStats.new.to_h
@throughput = ThroughputSparkline.new
+ @failures = FailedJobSparkline.new
end
end
end
diff --git a/app/helpers/solid_stack_web/application_helper.rb b/app/helpers/solid_stack_web/application_helper.rb
index 20b7c36..48ecb99 100644
--- a/app/helpers/solid_stack_web/application_helper.rb
+++ b/app/helpers/solid_stack_web/application_helper.rb
@@ -87,6 +87,17 @@ def queue_depth_sparkline_svg(sparkline)
end
end
+ def failed_job_sparkline_svg(sparkline)
+ build_sparkline_svg(sparkline, aria_label: "Failed jobs over the last 12 hours") do |count, i|
+ hours_ago = SolidStackWeb::FailedJobSparkline::HOURS - i
+ if hours_ago == 1
+ "#{count} #{count == 1 ? "failure" : "failures"} in the last hour"
+ else
+ "#{count} #{count == 1 ? "failure" : "failures"} (#{hours_ago}h–#{hours_ago - 1}h ago)"
+ end
+ end
+ end
+
private
def build_sparkline_svg(sparkline, css_class: "sqw-sparkline", aria_label: nil, &tooltip_text)
diff --git a/app/models/solid_stack_web/failed_job_sparkline.rb b/app/models/solid_stack_web/failed_job_sparkline.rb
new file mode 100644
index 0000000..617df57
--- /dev/null
+++ b/app/models/solid_stack_web/failed_job_sparkline.rb
@@ -0,0 +1,23 @@
+module SolidStackWeb
+ class FailedJobSparkline
+ HOURS = 12
+
+ def buckets
+ @buckets ||= begin
+ now = Time.current
+ origin = now - HOURS.hours
+ times = ::SolidQueue::FailedExecution.where(created_at: origin..now).pluck(:created_at)
+
+ HOURS.times.map do |i|
+ from = origin + i.hours
+ to = origin + (i + 1).hours
+ times.count { |t| t >= from && t < to }
+ end
+ end
+ end
+
+ def max
+ buckets.max || 0
+ end
+ end
+end
diff --git a/app/views/solid_stack_web/dashboard/index.html.erb b/app/views/solid_stack_web/dashboard/index.html.erb
index 79438fa..f6bbc99 100644
--- a/app/views/solid_stack_web/dashboard/index.html.erb
+++ b/app/views/solid_stack_web/dashboard/index.html.erb
@@ -68,6 +68,18 @@
now
+
+
Failures — last 12 hours
+
+ <%= failed_job_sparkline_svg(@failures) %>
+
+
+
+ 12h ago
+ 6h ago
+ now
+
+
diff --git a/spec/models/solid_stack_web/failed_job_sparkline_spec.rb b/spec/models/solid_stack_web/failed_job_sparkline_spec.rb
new file mode 100644
index 0000000..bce6fa1
--- /dev/null
+++ b/spec/models/solid_stack_web/failed_job_sparkline_spec.rb
@@ -0,0 +1,50 @@
+require "rails_helper"
+
+RSpec.describe SolidStackWeb::FailedJobSparkline do
+ def create_failed(created_at:)
+ SolidQueue::Job.skip_callback(:create, :after, :prepare_for_execution)
+ job = SolidQueue::Job.create!(class_name: "FailingJob", queue_name: "default",
+ priority: 0, arguments: {})
+ SolidQueue::FailedExecution.create!(
+ job: job,
+ error: { exception_class: "RuntimeError", message: "boom", backtrace: [] },
+ created_at: created_at
+ )
+ ensure
+ SolidQueue::Job.set_callback(:create, :after, :prepare_for_execution)
+ end
+
+ describe "#buckets" do
+ it "returns 12 buckets" do
+ expect(described_class.new.buckets.size).to eq(12)
+ end
+
+ it "returns all zeros when there are no failed executions" do
+ expect(described_class.new.buckets).to all(eq(0))
+ end
+
+ it "counts a failure within the window in the correct bucket" do
+ create_failed(created_at: 2.hours.ago)
+ buckets = described_class.new.buckets
+ expect(buckets[9]).to eq(1)
+ expect(buckets.sum).to eq(1)
+ end
+
+ it "excludes failures outside the 12-hour window" do
+ create_failed(created_at: 13.hours.ago)
+ expect(described_class.new.buckets).to all(eq(0))
+ end
+ end
+
+ describe "#max" do
+ it "returns 0 when there are no failures" do
+ expect(described_class.new.max).to eq(0)
+ end
+
+ it "returns the highest bucket count" do
+ 3.times { create_failed(created_at: 1.hour.ago) }
+ create_failed(created_at: 5.hours.ago)
+ expect(described_class.new.max).to eq(3)
+ end
+ end
+end