diff --git a/.github/create-issue-on-failure.md b/.github/create-issue-on-failure.md
new file mode 100644
index 000000000..c13edfff8
--- /dev/null
+++ b/.github/create-issue-on-failure.md
@@ -0,0 +1,13 @@
+---
+name: "Issue on workflow failure"
+about: "Issue template for workflow failures"
+title: 'Workflow "{{ env.WORKFLOW_NAME }}" failed'
+labels: "build-failure"
+---
+
+The workflow "**{{ env.WORKFLOW_NAME }}**" failed. See logs:
+https://github.com/{{ env.REPO_SLUG }}/actions/runs/{{ env.RUN_ID }}
+
+Commit: https://github.com/{{ env.REPO_SLUG }}/commit/{{ tools.context.sha }}
+
+// cc: {{ env.MENTION }} — please triage and resolve this issue
diff --git a/.github/workflows/test-timely-master.yml b/.github/workflows/test-timely-master.yml
new file mode 100644
index 000000000..2af4f1c35
--- /dev/null
+++ b/.github/workflows/test-timely-master.yml
@@ -0,0 +1,50 @@
+name: "Test build against Timely master"
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '38 3 * * *'
+
+jobs:
+  tests:
+    strategy:
+      matrix:
+        os:
+          - ubuntu
+        toolchain:
+          - stable
+    name: cargo test on ${{ matrix.os }}, rust ${{ matrix.toolchain }}
+    runs-on: ${{ matrix.os }}-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions-rust-lang/setup-rust-toolchain@v1
+        with:
+          toolchain: ${{ matrix.toolchain }}
+      - name: Cargo check against Timely master
+        working-directory: timely_master
+        run: cargo check --all-targets
+      - name: Cargo test against Timely master
+        working-directory: timely_master
+        run: cargo test
+
+  notify:
+    name: Notify failed build
+    if: failure() && github.event.pull_request == null
+    needs: [tests]
+    permissions:
+      contents: read
+      issues: write
+    runs-on: ubuntu-latest
+    steps:
+      # We need to checkout the repository to access the issue template
+      - uses: actions/checkout@v4
+      - uses: JasonEtco/create-an-issue@v2
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          WORKFLOW_NAME: ${{ github.workflow }}
+          REPO_SLUG: ${{ github.repository }}
+          RUN_ID: ${{ github.run_id }}
+          MENTION: '@frankmcsherry, @antiguru'
+        with:
+          filename: '.github/create-issue-on-failure.md'
+          update_existing: true
+          search_existing: open
diff --git a/.gitignore b/.gitignore
index 06aba01b6..fa8d85ac5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,2 @@
 Cargo.lock
-/target
+target
diff --git a/timely_master/Cargo.toml b/timely_master/Cargo.toml
new file mode 100644
index 000000000..3080b03a0
--- /dev/null
+++ b/timely_master/Cargo.toml
@@ -0,0 +1,10 @@
+# This is not part of the regular workspace.
+[workspace]
+members = ["differential-dataflow", "differential-dogs3"]
+resolver = "2"
+
+[workspace.dependencies]
+timely = { git = "https://github.com/TimelyDataflow/timely-dataflow", default-features = false }
+
+[patch.crates-io]
+timely = { git = "https://github.com/TimelyDataflow/timely-dataflow" }
diff --git a/timely_master/README.md b/timely_master/README.md
new file mode 100644
index 000000000..da3923f89
--- /dev/null
+++ b/timely_master/README.md
@@ -0,0 +1,7 @@
+# Tests for Differential against Timely master
+
+This directory contains tests for Differential against Timely master. The tests are run in the same way as the tests
+for Differential against released versions of Timely, but the crate is replaced with the `timely` crate from Github.
+
+Nobody should ever rely on the contents of this directory for any other purpose than testing differential
+against timely master.
diff --git a/timely_master/differential-dataflow/Cargo.toml b/timely_master/differential-dataflow/Cargo.toml
new file mode 100644
index 000000000..9c496fb2e
--- /dev/null
+++ b/timely_master/differential-dataflow/Cargo.toml
@@ -0,0 +1,21 @@
+[package]
+name = "differential-dataflow"
+version = "0.0.0"
+authors = ["Moritz Hoffmann <antiguru@gmail.com>"]
+license = "MIT"
+edition = "2021"
+publish = false
+description = "A fake package to test differential against timely master."
+
+# Point at the regular differential crate.
+[lib]
+path = "../../src/lib.rs"
+
+# Dependencies to build against timely master. Must mirror the dependencies in the main Cargo.toml.
+[dependencies]
+fnv="1.0.2"
+serde = { version = "1.0", features = ["derive"] }
+timely = { workspace = true }
+
+[features]
+default = ["timely/getopts"]
diff --git a/timely_master/differential-dogs3/Cargo.toml b/timely_master/differential-dogs3/Cargo.toml
new file mode 100644
index 000000000..1fc0ecfcd
--- /dev/null
+++ b/timely_master/differential-dogs3/Cargo.toml
@@ -0,0 +1,18 @@
+[package]
+name = "differential-dogs3"
+version = "0.0.0"
+authors = ["Moritz Hoffmann <antiguru@gmail.com>"]
+license = "MIT"
+edition = "2021"
+publish = false
+description = "A fake package to test dogsdogsdogs against timely master."
+
+# Point at the regular dogsdogsdogs crate.
+[lib]
+path = "../../dogsdogsdogs/src/lib.rs"
+
+# Dependencies to build against timely master. Must mirror the dependencies in the main Cargo.toml.
+[dependencies]
+differential-dataflow = { path = "../differential-dataflow", default-features = false }
+serde = { version = "1.0", features = ["derive"] }
+timely = { workspace = true }