diff --git a/.ackrc b/.ackrc
new file mode 100644
index 0000000..26be235
--- /dev/null
+++ b/.ackrc
@@ -0,0 +1 @@
+--ignore-dir=vendor
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..9933946
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+/monohook
+/release
+/vendor
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..1eba45e
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,18 @@
+language: go
+
+go:
+  - "1.7"
+  - "1.8"
+  - "1.9"
+  - "1.10"
+  - "1.11"
+  - "1.x"
+
+os: ubuntu
+dist: xenial
+
+before_install:
+  - curl https://raw.githubusercontent.com/golang/dep/master/install.sh | sh
+
+install:
+  - make install
diff --git a/Gopkg.lock b/Gopkg.lock
new file mode 100644
index 0000000..a8083c6
--- /dev/null
+++ b/Gopkg.lock
@@ -0,0 +1,61 @@
+# This file is autogenerated, do not edit; changes may be undone by the next 'dep ensure'.
+
+
+[[projects]]
+  branch = "master"
+  digest = "1:c6872fbc5399e91e4854bd32e842998722ed8419a82aa8a6aaeaad9068fcd0af"
+  name = "github.com/buildkite/interpolate"
+  packages = ["."]
+  pruneopts = ""
+  revision = "973457fa2b4c81e6b755ac41509d41f18027ca77"
+
+[[projects]]
+  digest = "1:e988ed0ca0d81f4d28772760c02ee95084961311291bdfefc1b04617c178b722"
+  name = "github.com/fatih/color"
+  packages = ["."]
+  pruneopts = ""
+  revision = "5b77d2a35fb0ede96d138fc9a99f5c9b6aef11b4"
+  version = "v1.7.0"
+
+[[projects]]
+  digest = "1:9ea83adf8e96d6304f394d40436f2eb44c1dc3250d223b74088cc253a6cd0a1c"
+  name = "github.com/mattn/go-colorable"
+  packages = ["."]
+  pruneopts = ""
+  revision = "167de6bfdfba052fa6b2d3664c8f5272e23c9072"
+  version = "v0.0.9"
+
+[[projects]]
+  digest = "1:d0600e4cf07697303f37130791b2ce4577367931416bea8ec4f601bde3f7c5bf"
+  name = "github.com/mattn/go-isatty"
+  packages = ["."]
+  pruneopts = ""
+  revision = "c2a7a6ca930a4cd0bc33a3f298eb71960732a3a7"
+  version = "v0.0.7"
+
+[[projects]]
+  digest = "1:cbaf13cdbfef0e4734ed8a7504f57fe893d471d62a35b982bf6fb3f036449a66"
+  name = "github.com/spf13/pflag"
+  packages = ["."]
+  pruneopts = ""
+  revision = "298182f68c66c05229eb03ac171abe6e309ee79a"
+  version = "v1.0.3"
+
+[[projects]]
+  branch = "master"
+  digest = "1:55c52474bb389797ed66db92966e2b9ddc98a25d9d05c8aa55787fe03d4d4084"
+  name = "golang.org/x/sys"
+  packages = ["unix"]
+  pruneopts = ""
+  revision = "4b34438f7a67ee5f45cc6132e2bad873a20324e9"
+
+[solve-meta]
+  analyzer-name = "dep"
+  analyzer-version = 1
+  input-imports = [
+    "github.com/buildkite/interpolate",
+    "github.com/fatih/color",
+    "github.com/spf13/pflag",
+  ]
+  solver-name = "gps-cdcl"
+  solver-version = 1
diff --git a/Gopkg.toml b/Gopkg.toml
new file mode 100644
index 0000000..328d9fb
--- /dev/null
+++ b/Gopkg.toml
@@ -0,0 +1,32 @@
+# Gopkg.toml example
+#
+# Refer to https://github.com/golang/dep/blob/master/docs/Gopkg.toml.md
+# for detailed Gopkg.toml documentation.
+#
+# required = ["github.com/user/thing/cmd/thing"]
+# ignored = ["github.com/user/project/pkgX", "bitbucket.org/user/project/pkgA/pkgY"]
+#
+# [[constraint]]
+#   name = "github.com/user/project"
+#   version = "1.0.0"
+#
+# [[constraint]]
+#   name = "github.com/user/project2"
+#   branch = "dev"
+#   source = "github.com/myfork/project2"
+#
+# [[override]]
+#  name = "github.com/x/y"
+#  version = "2.4.0"
+
+[[constraint]]
+  name = "github.com/fatih/color"
+  version = "1.5.0"
+
+[[constraint]]
+  name = "github.com/spf13/pflag"
+  version = "1.0.0"
+
+[[constraint]]
+  branch = "master"
+  name = "github.com/buildkite/interpolate"
diff --git a/LICENSE.txt b/LICENSE.txt
new file mode 100644
index 0000000..dffd084
--- /dev/null
+++ b/LICENSE.txt
@@ -0,0 +1,20 @@
+Copyright (c) 2019 Simon Oulevay (Alpha Hydrae)
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..fb8da1b
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,13 @@
+SHELL := /usr/bin/env bash
+
+test:
+	go test -count=1 -v ./...
+
+install:
+	dep ensure
+
+build:
+	./scripts/build.sh
+
+doctoc:
+	command -v doctoc &>/dev/null && doctoc README.md || { >&2 echo "Error: install doctoc with \`npm install -g doctoc\`"; exit 1; }
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..aa2a228
--- /dev/null
+++ b/README.md
@@ -0,0 +1,86 @@
+# monohook
+
+Run a single HTTP webhook endpoint that executes a command (e.g. a deployment script).
+
+```
+$> monohook --authorization letmein --concurrency 1 --port 3000 -- deploy.sh
+```
+
+<!-- START doctoc generated TOC please keep comment here to allow auto update -->
+<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
+
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+
+[![version](https://img.shields.io/badge/Version-v1.0.0-blue.svg)](https://github.com/AlphaHydrae/monohook/releases/tag/v1.0.0)
+[![build status](https://travis-ci.org/AlphaHydrae/monohook.svg?branch=master)](https://travis-ci.org/AlphaHydrae/monohook)
+[![license](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE.txt)
+
+
+
+## Installation
+
+* **Linux**
+
+  ```
+  wget -O /usr/local/bin/monohook \
+    https://github.com/AlphaHydrae/monohook/releases/download/v2.2.0/monohook_linux_amd64 && \
+    chmod +x /usr/local/bin/monohook
+  ```
+* **Linux (arm64)**
+
+  ```
+  wget -O /usr/local/bin/monohook \
+    https://github.com/AlphaHydrae/monohook/releases/download/v2.2.0/monohook_linux_arm64 && \
+    chmod +x /usr/local/bin/monohook
+  ```
+* **macOS**
+
+  ```
+  wget -O /usr/local/bin/monohook \
+    https://github.com/AlphaHydrae/monohook/releases/download/v2.2.0/monohook_darwin_amd64 && \
+    chmod +x /usr/local/bin/monohook
+  ```
+* **Windows**
+
+  ```
+  wget -O /usr/local/bin/monohook \
+    https://github.com/AlphaHydrae/monohook/releases/download/v2.2.0/monohook_windows_amd64 && \
+    chmod +x /usr/local/bin/monohook
+  ```
+
+
+
+## Usage
+
+```
+monohook runs a single HTTP webhook endpoint that executes a command.
+
+Usage:
+  monohook [OPTION...] [--] [EXEC...]
+
+Options:
+  -a, --authorization string   Bearer token that must be sent in the Authorization header to authenticate
+  -b, --buffer string          Maximum number of requests to queue before refusing subsequent ones until the queue is freed (zero for infinite) (default "10")
+  -c, --concurrency string     Maximum number of times the command should be executed in parallel (zero for infinite concurrency) (default "1")
+  -C, --cwd string             Working directory in which to run the command
+  -p, --port string            Port on which to listen to (default "5000")
+  -q, --quiet                  Do not print anything (default false)
+
+Examples:
+  Update a file when the hook is triggered:
+    monohook -- touch hooked.txt
+  Deploy an application when the hook is triggered:
+    monohook -a letmein -- deploy-stuff.sh
+```
+
+
+
+## Exit codes
+
+**monohook** may exit with the following status codes:
+
+Code | Description
+:--- | :---
+`1`  | Invalid arguments were given.
+`2`  | An unrecoverable error occurred while trying to interpolate environment variables into options or command arguments.
+`3`  | The command to execute (provided after `--`) could not be found in the `$PATH`.
diff --git a/monohook.go b/monohook.go
new file mode 100644
index 0000000..70a141b
--- /dev/null
+++ b/monohook.go
@@ -0,0 +1,228 @@
+// The monohook command runs a single HTTP webhook endpoint that executes a command.
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"os/exec"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/buildkite/interpolate"
+	"github.com/fatih/color"
+	flag "github.com/spf13/pflag"
+)
+
+const usageHeader = `%s runs a single HTTP webhook endpoint that executes a command.
+
+Usage:
+  %s [OPTION...] [--] [EXEC...]
+
+Options:
+`
+
+const usageFooter = `
+Examples:
+  Update a file when the hook is triggered:
+    monohook -- touch hooked.txt
+  Deploy an application when the hook is triggered:
+    monohook -a letmein -- deploy-stuff.sh
+`
+
+type commandOptions struct {
+	command string
+	args    []string
+	cwd     string
+}
+
+func main() {
+
+	var authString string
+	var bufferString string
+	var concurrencyString string
+	var cwdString string
+	var quiet bool
+	var portString string
+
+	flag.CommandLine.SetOutput(os.Stdout)
+
+	flag.StringVarP(&authString, "authorization", "a", "", "Bearer token that must be sent in the Authorization header to authenticate")
+	flag.StringVarP(&bufferString, "buffer", "b", "10", "Maximum number of requests to queue before refusing subsequent ones until the queue is freed (zero for infinite)")
+	flag.StringVarP(&concurrencyString, "concurrency", "c", "1", "Maximum number of times the command should be executed in parallel (zero for infinite concurrency)")
+	flag.StringVarP(&cwdString, "cwd", "C", "", "Working directory in which to run the command")
+	flag.BoolVarP(&quiet, "quiet", "q", false, "Do not print anything (default false)")
+	flag.StringVarP(&portString, "port", "p", "5000", "Port on which to listen to")
+
+	flag.Usage = func() {
+		fmt.Printf(usageHeader, os.Args[0], os.Args[0])
+		flag.PrintDefaults()
+		fmt.Print(usageFooter)
+	}
+
+	flag.Parse()
+
+	auth := parseStringOption(authString, "authorization", quiet)
+	buffer := parseUint64Option(bufferString, "buffer", quiet)
+	concurrency := parseUint64Option(concurrencyString, "concurrency", quiet)
+	cwd := parseStringOption(cwdString, "cwd", quiet)
+	port := parseUint64Option(portString, "port", quiet)
+
+	if port > 65535 {
+		fail(1, quiet, "port number must be smaller than or equal to 65535")
+	}
+
+	terminator := -1
+	for i := 0; i < len(os.Args); i++ {
+		if os.Args[i] == "--" {
+			terminator = i
+			break
+		}
+	}
+
+	var extra []string
+	var execCommand string
+	var execArgs []string
+	if terminator >= 0 && terminator < len(os.Args)-1 {
+		extra = flag.Args()[0 : len(flag.Args())-(len(os.Args)-terminator-1)]
+
+		var err error
+		execCommand, err = exec.LookPath(parseStringOption(os.Args[terminator+1], "command", quiet))
+		if err != nil {
+			fail(3, quiet, "could not find command \"%s\"", os.Args[terminator+1])
+		}
+
+		execArgs = os.Args[terminator+2 : len(os.Args)]
+
+		for k := range execArgs {
+			execArgs[k] = parseStringOption(execArgs[k], "command argument "+strconv.FormatInt(int64(k), 10), quiet)
+		}
+	} else {
+		extra = flag.Args()
+	}
+
+	if len(extra) != 0 {
+		fail(1, quiet, "no argument expected before the terminator")
+	} else if execCommand == "" {
+		fail(1, quiet, "no command to execute was provided")
+	}
+
+	opts := &commandOptions{}
+	opts.command = execCommand
+	opts.args = execArgs
+	opts.cwd = cwd
+
+	execCh := make(chan *commandOptions, buffer)
+
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+
+		if auth != "" {
+			// Refuse request if unauthorized.
+			header := r.Header.Get("Authorization")
+			if header == "" || header[0:7] != "Bearer " || header[7:] != auth {
+				w.WriteHeader(403)
+				return
+			}
+		}
+
+		// Refuse extra requests if buffer is full.
+		select {
+		case execCh <- opts:
+			w.WriteHeader(202)
+		default:
+			w.WriteHeader(429)
+		}
+	})
+
+	s := &http.Server{
+		Addr:           ":" + strconv.FormatUint(port, 10),
+		Handler:        nil,
+		ReadTimeout:    10 * time.Second,
+		WriteTimeout:   10 * time.Second,
+		MaxHeaderBytes: 1 << 20,
+	}
+
+	go worker(concurrency, execCh)
+
+	s.ListenAndServe()
+}
+
+func interpolateValue(value string) (string, error) {
+	return interpolate.Interpolate(interpolate.NewSliceEnv(os.Environ()), value)
+}
+
+func parseStringOption(value string, name string, quiet bool) string {
+
+	interpolated, err := interpolateValue(value)
+	if err != nil {
+		fail(2, quiet, "%s could not be interpolated", name)
+	}
+
+	return interpolated
+}
+
+func parseUint64Option(value string, name string, quiet bool) uint64 {
+
+	interpolated, err := interpolate.Interpolate(interpolate.NewSliceEnv(os.Environ()), value)
+	if err != nil {
+		fail(2, quiet, "the \"%s\" option could not be interpolated", name)
+	}
+
+	parsed, err := strconv.ParseUint(interpolated, 10, 64)
+	if err != nil {
+		fail(1, quiet, "the \"%s\" option must be an unsigned 64-bit integer", name)
+	}
+
+	return parsed
+}
+
+func worker(concurrency uint64, execChannel chan *commandOptions) {
+	fmt.Fprintf(os.Stderr, "Execution worker started\n")
+
+	n := uint64(0)
+	wait := &sync.WaitGroup{}
+
+	for job := range execChannel {
+
+		if concurrency >= 1 {
+			n++
+			wait.Add(1)
+		}
+
+		go execCommand(job, wait)
+
+		// Wait for queue to clear if concurrency is limited.
+		if concurrency >= 1 && n >= concurrency {
+			wait.Wait()
+			n -= concurrency
+		}
+	}
+}
+
+func execCommand(opts *commandOptions, waitGroup *sync.WaitGroup) {
+
+	fmt.Fprintf(os.Stderr, "Executing %s\n", opts.command)
+
+	cmd := exec.Command(opts.command, opts.args...)
+	cmd.Env = os.Environ()
+	cmd.Stderr = os.Stdout
+	cmd.Stdout = os.Stdout
+
+	err := cmd.Run()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, color.RedString("Command %s error: %s\n"), opts.command, err)
+	} else {
+		fmt.Fprintf(os.Stderr, color.GreenString("Successfully executed %s\n"), opts.command)
+	}
+
+	waitGroup.Done()
+}
+
+func fail(code int, quiet bool, format string, values ...interface{}) {
+	if !quiet {
+		fmt.Fprintf(os.Stderr, color.RedString("Error: "+format+"\n"), values...)
+	}
+
+	os.Exit(code)
+}
diff --git a/scripts/build.sh b/scripts/build.sh
new file mode 100755
index 0000000..beb51d9
--- /dev/null
+++ b/scripts/build.sh
@@ -0,0 +1,36 @@
+#!/usr/bin/env bash
+set -e
+
+bold=$(tput bold)
+normal=$(tput sgr0)
+versions="darwin_amd64 linux_amd64 linux_arm64 windows_amd64"
+
+test -z "$RELEASE" && RELEASE="$(git describe --tags || echo -n)"
+
+if test -z "$RELEASE"; then
+  >&2 echo No Git tag found
+  exit 1
+fi
+
+rm -fr release/${RELEASE}
+
+printf "\n${bold}○ Building binaries...${normal}\n"
+
+for version in $versions; do
+  os="$(echo $version | cut -d _ -f 1)"
+  arch="$(echo $version | cut -d _ -f 2)"
+  env GOOS=$os GOARCH=$arch go build -ldflags="-s -w" -o release/${RELEASE}/monohook_${os}_${arch} &
+done
+
+wait
+
+for version in $versions; do
+  file="release/${RELEASE}/monohook_${version}"
+  printf "\n${bold}○ Compressing ${file}...${normal}\n\n"
+  upx --ultra-brute "$file"
+done
+
+printf "\n${bold}○ Calculating digests...${normal}\n\n"
+dgstore 'release/**/*'
+
+echo