diff --git a/.circleci/config.yml b/.circleci/config.yml
deleted file mode 100644
index d4270c7a..00000000
--- a/.circleci/config.yml
+++ /dev/null
@@ -1,71 +0,0 @@
----
-version: 2.1
-orbs:
-  prometheus: prometheus/prometheus@0.17.1
-executors:
-  golang:
-    docker:
-      - image: cimg/go:1.25
-      - image: quay.io/prometheus/node-exporter:latest
-
-jobs:
-  test:
-    executor: golang
-    environment:
-      prom_ver: 3.7.3
-    steps:
-      - prometheus/setup_environment
-      - run: wget https://github.com/prometheus/prometheus/releases/download/v${prom_ver}/prometheus-${prom_ver}.linux-amd64.tar.gz
-      - run: tar xzf prometheus-${prom_ver}.linux-amd64.tar.gz
-      - run: sudo cp -v prometheus-${prom_ver}.linux-amd64/prometheus /bin/prometheus
-      - run:
-          name: Configure Prometheus
-          command: |
-            cat \<< EOF > prometheus.yml
-            global:
-              scrape_interval: 1s
-            scrape_configs:
-              - job_name: pushprox
-                proxy_url: http://127.0.0.1:8080
-                static_configs:
-                  - targets: ['$(hostname):9100']
-            EOF
-      - run: make
-      - run:
-          name: Run everything and test that Prometheus can scrape node_exporter via pushprox
-          command: ./end-to-end-test.sh
-workflows:
-  version: 2
-  PushProx:
-    jobs:
-      - test:
-          filters:
-            tags:
-              only: /.*/
-      - prometheus/build:
-          name: build
-          filters:
-            tags:
-              only: /.*/
-      - prometheus/publish_master:
-          context: org-context
-          docker_hub_organization: prometheuscommunity
-          quay_io_organization: prometheuscommunity
-          requires:
-            - test
-            - build
-          filters:
-            branches:
-              only: master
-      - prometheus/publish_release:
-          context: org-context
-          docker_hub_organization: prometheuscommunity
-          quay_io_organization: prometheuscommunity
-          requires:
-            - test
-            - build
-          filters:
-            tags:
-              only: /^v.*/
-            branches:
-              ignore: /.*/
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 00000000..8f8eaae5
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,78 @@
+---
+name: CI
+on:
+  pull_request:
+  push:
+    branches: [main, master, 'release-*']
+    tags: ['v*']
+
+permissions:
+  contents: read
+
+jobs:
+  test_go:
+    name: Go tests
+    runs-on: ubuntu-latest
+    container:
+      # Whenever the Go version is updated here, .promu.yml
+      # should also be updated.
+      image: quay.io/prometheus/golang-builder:1.26-base
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
+      - uses: prometheus/promci-setup@5af30ba8c199a91d6c04ebdc3c48e630e355f62d # v0.1.0
+      - run: make GO_ONLY=1 SKIP_GOLANGCI_LINT=1
+      - run: git diff --exit-code
+
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        thread: [ 0, 1, 2, 3]
+    steps:
+      - uses: prometheus/promci/build@d9d4f5688814f0b77bf003d07fb8c00507390634 # v0.8.2
+        with:
+          parallelism: 4
+          thread: ${{ matrix.thread }}
+
+  publish_default:
+    name: Publish default branch artifacts
+    runs-on: ubuntu-latest
+    permissions:
+      packages: write
+    needs: [test_go, build]
+    if: |
+      (github.event_name == 'push' && github.event.ref == 'refs/heads/main')
+      ||
+      (github.event_name == 'push' && github.event.ref == 'refs/heads/master')
+    steps:
+      - uses: prometheus/promci/publish_main@13941414d409d227afd67544e5d306827db5a1a2 # v0.8.5
+        with:
+          docker_hub_organization: prometheuscommunity
+          docker_hub_password: ${{ secrets.docker_hub_password }}
+          ghcr_io_organization: prometheus-community
+          ghcr_io_password: ${{ github.token }}
+          quay_io_organization: prometheuscommunity
+          quay_io_password: ${{ secrets.quay_io_password }}
+
+  publish_release:
+    name: Publish release artefacts
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      packages: write
+    needs: [test_go, build]
+    if: |
+      (github.event_name == 'push' && startsWith(github.ref, 'refs/tags/v'))
+    steps:
+      - uses: prometheus/promci/publish_release@d9d4f5688814f0b77bf003d07fb8c00507390634 # v0.8.2
+        with:
+          docker_hub_organization: prometheuscommunity
+          docker_hub_password: ${{ secrets.docker_hub_password }}
+          ghcr_io_organization: prometheus-community
+          ghcr_io_password: ${{ github.token }}
+          quay_io_organization: prometheuscommunity
+          quay_io_password: ${{ secrets.quay_io_password }}
+          github_token: ${{ github.token }}
diff --git a/.github/workflows/integration.yml b/.github/workflows/integration.yml
new file mode 100644
index 00000000..f0caccaf
--- /dev/null
+++ b/.github/workflows/integration.yml
@@ -0,0 +1,33 @@
+---
+name: Integration
+on:
+  pull_request:
+  push:
+    branches: [main, master, 'release-*']
+    tags: ['v*']
+
+permissions:
+  contents: read
+
+jobs:
+  integration:
+    name: Integration test
+    runs-on: ubuntu-latest
+    services:
+      node-exporter:
+        image: quay.io/prometheus/node-exporter:latest
+        ports:
+          - 9100:9100
+    env:
+      PROM_VERSION: 3.12.0
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - uses: actions/setup-go@924ae3a1cded613372ab5595356fb5720e22ba16 # v6.5.0
+        with:
+          go-version: 1.26.x
+      - run: make build
+      - run: curl -sSf -L https://github.com/prometheus/prometheus/releases/download/v${PROM_VERSION}/prometheus-${PROM_VERSION}.linux-amd64.tar.gz | tar xz
+      - run: sudo cp -v prometheus-${PROM_VERSION}.linux-amd64/prometheus /usr/bin/prometheus
+      - run: sed -i "s/node-exporter/${HOSTNAME}/" ./end-to-end/prometheus.yml
+      - run: cat ./end-to-end/prometheus.yml
+      - run: ./end-to-end/test.sh
diff --git a/.promu.yml b/.promu.yml
index 05f1645f..cfcc84ff 100644
--- a/.promu.yml
+++ b/.promu.yml
@@ -1,6 +1,6 @@
 go:
-    # This must match .circle/config.yml.
-    version: 1.25
+    # This must match .github/workflows/ci.yml.
+    version: 1.26
 repository:
     path: github.com/prometheus-community/pushprox
 build:
diff --git a/end-to-end-test.sh b/end-to-end-test.sh
deleted file mode 100755
index 3ceb681b..00000000
--- a/end-to-end-test.sh
+++ /dev/null
@@ -1,51 +0,0 @@
-#!/bin/bash
-
-set -u -o pipefail
-
-tmpdir=$(mktemp -d /tmp/pushprox_e2e_test.XXXXXX)
-
-cleanup() {
-  for f in "${tmpdir}"/*.pid ; do
-    kill -9 "$(< $f)"
-  done
-  rm -r "${tmpdir}"
-}
-
-trap cleanup EXIT
-
-if type node_exporter > /dev/null 2>&1 ; then
-  node_exporter &
-  echo $! > "${tmpdir}/node_exporter.pid"
-fi
-while ! curl -s -f -L http://localhost:9100; do
-  echo 'Waiting for node_exporter'
-  sleep 2
-done
-
-./pushprox-proxy --log.level=debug &
-echo $! > "${tmpdir}/proxy.pid"
-while ! curl -s -f -L http://localhost:8080/clients; do
-  echo 'Waiting for proxy'
-  sleep 2
-done
-
-./pushprox-client  --log.level=debug --proxy-url=http://localhost:8080 &
-echo $! > "${tmpdir}/client.pid"
-while [ "$(curl -s -L 'http://localhost:8080/clients' | jq 'length')" != '1' ] ; do
-  echo 'Waiting for client'
-  sleep 2
-done
-
-prometheus --config.file=prometheus.yml --log.level=debug &
-echo $! > "${tmpdir}/prometheus.pid"
-while ! curl -s -f -L http://localhost:9090/-/ready; do
-  echo 'Waiting for Prometheus'
-  sleep 2
-done
-sleep 15
-
-query='http://localhost:9090/api/v1/query?query=node_exporter_build_info'
-while [ $(curl -s -L "${query}" | jq '.data.result | length') != '1' ]; do
-  echo 'Waiting for results'
-  sleep 2
-done
diff --git a/end-to-end/prometheus.yml b/end-to-end/prometheus.yml
new file mode 100644
index 00000000..58488776
--- /dev/null
+++ b/end-to-end/prometheus.yml
@@ -0,0 +1,8 @@
+global:
+  scrape_interval: 1s
+scrape_configs:
+  - job_name: pushprox
+    proxy_url: http://localhost:8080
+    static_configs:
+      - targets:
+          - node-exporter:9100
diff --git a/end-to-end/test.sh b/end-to-end/test.sh
new file mode 100755
index 00000000..37a7350b
--- /dev/null
+++ b/end-to-end/test.sh
@@ -0,0 +1,84 @@
+#!/usr/bin/env bash
+
+set -u -o pipefail
+
+tmpdir=$(mktemp -d /tmp/pushprox_e2e_test.XXXXXX)
+
+cleanup() {
+  for f in "${tmpdir}"/*.pid ; do
+    kill -9 "$(< $f)"
+  done
+  rm -r "${tmpdir}"
+}
+
+trap cleanup EXIT
+
+get_clients() {
+  curl -s -f -L http://localhost:8080/clients
+}
+
+run_client() {
+  ./pushprox-client --log.level=debug --fqdn="${HOSTNAME}" --proxy-url=http://localhost:8080 2>&1 | sed 's/^/pushprox-client: /'
+}
+
+run_proxy() {
+  ./pushprox-proxy --log.level=debug 2>&1 | sed 's/^/pushprox-proxy: /'
+}
+
+run_node_exporter() {
+  node_exporter 2>&1 | sed 's/^/node_exporter: /'
+}
+
+run_prometheus() {
+  prometheus --config.file=end-to-end/prometheus.yml --log.level=debug 2>&1 | sed 's/^/prometheus: /'
+}
+
+if type node_exporter > /dev/null 2>&1 ; then
+  echo "INFO: Starting node_exporter"
+  run_node_exporter &
+  pidof node_exporter > "${tmpdir}/node_exporter.pid"
+fi
+while ! curl -s -f -L "http://localhost:9100" > /dev/null; do
+  echo 'INFO: Waiting for node_exporter'
+  sleep 2
+done
+
+if [[ ! -f 'pushprox-proxy' ]] ; then
+  echo 'ERROR: Missing pushprox-proxy binary'
+  exit 1
+fi
+run_proxy &
+pidof pushprox-proxy > "${tmpdir}/proxy.pid"
+while ! get_clients > /dev/null; do
+  echo 'INFO: Waiting for proxy'
+  sleep 2
+done
+
+if [[ ! -f 'pushprox-client' ]] ; then
+  echo 'ERROR: Missing pushprox-client binary'
+  exit 1
+fi
+run_client &
+pidof pushproxy-proxy > "${tmpdir}/client.pid"
+while [ "$(get_clients | jq 'length')" != '1' ] ; do
+  echo 'INFO: Waiting for client'
+  sleep 2
+done
+
+echo "INFO: Found clients: $(get_clients | jq -rc .)"
+
+if type prometheus > /dev/null 2>&1 ; then
+  run_prometheus &
+  pidof prometheus > "${tmpdir}/prometheus.pid"
+fi
+while ! curl -s -f -L "http://localhost:9090/-/ready"; do
+  echo 'INFO: Waiting for Prometheus'
+  sleep 2
+done
+sleep 15
+
+query="http://localhost:9090/api/v1/query?query=node_exporter_build_info"
+while [ $(curl -s -L "${query}" | jq '.data.result | length') != '1' ]; do
+  echo 'INFO: Waiting for results'
+  sleep 2
+done