diff --git a/lib/color-formatters.js b/lib/color-formatters.js
new file mode 100644
index 0000000000000..cf291e0be3528
--- /dev/null
+++ b/lib/color-formatters.js
@@ -0,0 +1,45 @@
+/**
+ * Commonly-used functions for determining the colour to use for a badge,
+ * including colours based off download count, version number, etc.
+ */
+'use strict';
+
+function versionFormatter(version) {
+  var first = version[0];
+  if (first === 'v') {
+    first = version[1];
+  } else if (/^[0-9]/.test(version)) {
+    version = 'v' + version;
+  }
+  if (first === '0' || (version.indexOf('-') !== -1)) {
+    return { version: version, color: 'orange' };
+  } else {
+    return { version: version, color: 'blue' };
+  }
+}
+exports.version = versionFormatter;
+
+function downloadCount(downloads) {
+  return floorCount(downloads, 10, 100, 1000);
+}
+exports.downloadCount = downloadCount;
+
+function coveragePercentage(percentage) {
+  return floorCount(percentage, 80, 90, 100);
+}
+exports.coveragePercentage = coveragePercentage;
+
+function floorCount(value, yellow, yellowgreen, green) {
+  if (value === 0) {
+    return 'red';
+  } else if (value < yellow) {
+    return 'yellow';
+  } else if (value < yellowgreen) {
+    return 'yellowgreen';
+  } else if (value < green) {
+    return 'green';
+  } else {
+    return 'brightgreen';
+  }
+}
+exports.floorCount = floorCount;
diff --git a/lib/php-version.js b/lib/php-version.js
new file mode 100644
index 0000000000000..fa501612253dc
--- /dev/null
+++ b/lib/php-version.js
@@ -0,0 +1,181 @@
+/**
+ * Utilities relating to PHP version numbers. This compares version numbers
+ * using the algorithm followed by Composer (see
+ * https://getcomposer.org/doc/04-schema.md#version).
+ */
+'use strict';
+
+const {listCompare} = require('./version.js');
+
+// Return a negative value if v1 < v2,
+// zero if v1 = v2,
+// a positive value otherwise.
+//
+// See https://getcomposer.org/doc/04-schema.md#version
+// and https://github.com/badges/shields/issues/319#issuecomment-74411045
+function compare(v1, v2) {
+  // Omit the starting `v`.
+  var rawv1 = omitv(v1);
+  var rawv2 = omitv(v2);
+  try {
+    var v1data = numberedVersionData(rawv1);
+    var v2data = numberedVersionData(rawv2);
+  } catch(e) {
+    return asciiVersionCompare(rawv1, rawv2);
+  }
+
+  // Compare the numbered part (eg, 1.0.0 < 2.0.0).
+  var numbersCompare = listCompare(v1data.numbers, v2data.numbers);
+  if (numbersCompare !== 0) {
+    return numbersCompare;
+  }
+
+  // Compare the modifiers (eg, alpha < beta).
+  if (v1data.modifier < v2data.modifier) {
+    return -1;
+  } else if (v1data.modifier > v2data.modifier) {
+    return 1;
+  }
+
+  // Compare the modifier counts (eg, alpha1 < alpha3).
+  if (v1data.modifierCount < v2data.modifierCount) {
+    return -1;
+  } else if (v1data.modifierCount > v2data.modifierCount) {
+    return 1;
+  }
+
+  return 0;
+}
+exports.compare = compare;
+
+function latest(versions) {
+  var latest = versions[0];
+  for (var i = 1; i < versions.length; i++) {
+    if (compare(latest, versions[i]) < 0) {
+      latest = versions[i];
+    }
+  }
+  return latest;
+}
+exports.latest = latest;
+
+// Whether a version is stable.
+function isStable(version) {
+  var rawVersion = omitv(version);
+  try {
+    var versionData = numberedVersionData(rawVersion);
+  } catch(e) {
+    return false;
+  }
+  // normal or patch
+  return (versionData.modifier === 3) || (versionData.modifier === 4);
+}
+exports.isStable = isStable;
+
+// === Private helper functions ===
+
+// Remove the starting v in a string.
+function omitv(version) {
+  if (version.charCodeAt(0) === 118) { // v
+    return version.slice(1);
+  } else {
+    return version;
+  }
+}
+
+// Return a negative value if v1 < v2,
+// zero if v1 = v2, a positive value otherwise.
+function asciiVersionCompare(v1, v2) {
+  if (v1 < v2) {
+    return -1;
+  } else if (v1 > v2) {
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
+// Take a version without the starting v.
+// eg, '1.0.x-beta'
+// Return { numbers: [1,0,something big], modifier: 2, modifierCount: 1 }
+function numberedVersionData(version) {
+  // A version has a numbered part and a modifier part
+  // (eg, 1.0.0-patch, 2.0.x-dev).
+  var parts = version.split('-');
+  var numbered = parts[0];
+
+  // Aliases that get caught here.
+  if (numbered === 'dev') {
+    return {
+      numbers: parts[1],
+      modifier: 5,
+      modifierCount: 1,
+    };
+  }
+
+  var modifierLevel = 3;
+  var modifierLevelCount = 0;
+
+  if (parts.length > 1) {
+    var modifier = parts[parts.length - 1];
+    var firstLetter = modifier.charCodeAt(0);
+    var modifierLevelCountString;
+
+    // Modifiers: alpha < beta < RC < normal < patch < dev
+    if (firstLetter === 97) { // a
+      modifierLevel = 0;
+      if (/^alpha/.test(modifier)) {
+        modifierLevelCountString = + (modifier.slice(5));
+      } else {
+        modifierLevelCountString = + (modifier.slice(1));
+      }
+    } else if (firstLetter === 98) { // b
+      modifierLevel = 1;
+      if (/^beta/.test(modifier)) {
+        modifierLevelCountString = + (modifier.slice(4));
+      } else {
+        modifierLevelCountString = + (modifier.slice(1));
+      }
+    } else if (firstLetter === 82) { // R
+      modifierLevel = 2;
+      modifierLevelCountString = + (modifier.slice(2));
+    } else if (firstLetter === 112) { // p
+      modifierLevel = 4;
+      if (/^patch/.test(modifier)) {
+        modifierLevelCountString = + (modifier.slice(5));
+      } else {
+        modifierLevelCountString = + (modifier.slice(1));
+      }
+    } else if (firstLetter === 100) { // d
+      modifierLevel = 5;
+      if (/^dev/.test(modifier)) {
+        modifierLevelCountString = + (modifier.slice(3));
+      } else {
+        modifierLevelCountString = + (modifier.slice(1));
+      }
+    }
+
+    // If we got the empty string, it defaults to a modifier count of 1.
+    if (!modifierLevelCountString) {
+      modifierLevelCount = 1;
+    } else {
+      modifierLevelCount = + modifierLevelCountString;
+    }
+  }
+
+  // Try to convert to a list of numbers.
+  var toNum = function(s) {
+    var n = +s;
+    if (n !== n) {  // If n is NaN…
+      n = 0xffffffff;
+    }
+    return n;
+  };
+  var numberList = numbered.split('.').map(toNum);
+
+  return {
+    numbers: numberList,
+    modifier: modifierLevel,
+    modifierCount: modifierLevelCount,
+  };
+}
diff --git a/lib/text-formatters.js b/lib/text-formatters.js
new file mode 100644
index 0000000000000..24a0bafd87c11
--- /dev/null
+++ b/lib/text-formatters.js
@@ -0,0 +1,47 @@
+/**
+ * Commonly-used functions for formatting text in badge labels. Includes
+ * ordinal numbers, currency codes, star ratings, etc.
+ */
+'use strict';
+
+function starRating(rating) {
+  var stars = '';
+  while (stars.length < rating) { stars += '★'; }
+  while (stars.length < 5) { stars += '☆'; }
+  return stars;
+}
+exports.starRating = starRating;
+
+// Convert ISO 4217 code to unicode string.
+function currencyFromCode(code) {
+  return ({
+    CNY: '¥',
+    EUR: '€',
+    GBP: '₤',
+    USD: '$',
+  })[code] || code;
+}
+exports.currencyFromCode = currencyFromCode;
+
+function ordinalNumber(n) {
+  var s=["ᵗʰ","ˢᵗ","ⁿᵈ","ʳᵈ"], v=n%100;
+  return n+(s[(v-20)%10]||s[v]||s[0]);
+}
+exports.ordinalNumber = ordinalNumber;
+
+// Given a number, string with appropriate unit in the metric system, SI.
+// Note: numbers beyond the peta- cannot be represented as integers in JS.
+var metricPrefix = ['k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'];
+var metricPower = metricPrefix
+    .map(function(a, i) { return Math.pow(1000, i + 1); });
+function metric(n) {
+  for (var i = metricPrefix.length - 1; i >= 0; i--) {
+    var limit = metricPower[i];
+    if (n >= limit) {
+      n = Math.round(n / limit);
+      return ''+n + metricPrefix[i];
+    }
+  }
+  return ''+n;
+}
+exports.metric = metric;
diff --git a/lib/version.js b/lib/version.js
new file mode 100644
index 0000000000000..09b7d5500b922
--- /dev/null
+++ b/lib/version.js
@@ -0,0 +1,80 @@
+/**
+ * Utilities relating to generating badges relating to version numbers. Includes
+ * comparing versions to determine the latest, and determining the color to use
+ * for the badge based on whether the version is a stable release.
+ *
+ * For utilities specific to PHP version ranges, see php-version.js.
+ */
+'use strict';
+
+const semver = require('semver');
+
+// Given a list of versions (as strings), return the latest version.
+// Return undefined if no version could be found.
+function latest(versions) {
+  var version = '';
+  var origVersions = versions;
+  versions = versions.filter(function(version) {
+    return (/^v?[0-9]/).test(version);
+  });
+  try {
+    version = semver.maxSatisfying(versions, '');
+  } catch(e) {
+    version = latestDottedVersion(versions);
+  }
+  if (version === undefined) {
+    origVersions = origVersions.sort();
+    version = origVersions[origVersions.length - 1];
+  }
+  return version;
+}
+exports.latest = latest;
+
+function listCompare(a, b) {
+  var alen = a.length, blen = b.length;
+  for (var i = 0; i < alen; i++) {
+    if (a[i] < b[i]) {
+      return -1;
+    } else if (a[i] > b[i]) {
+      return 1;
+    }
+  }
+  return alen - blen;
+}
+exports.listCompare = listCompare;
+
+// === Private helper functions ===
+
+// Take a list of string versions.
+// Return the latest, or undefined, if there are none.
+function latestDottedVersion(versions) {
+  var len = versions.length;
+  if (len === 0) { return; }
+  var version = versions[0];
+  for (var i = 1; i < len; i++) {
+    if (compareDottedVersion(version, versions[i]) < 0) {
+      version = versions[i];
+    }
+  }
+  return version;
+}
+
+// Take string versions.
+// -1 if v1 < v2, 1 if v1 > v2, 0 otherwise.
+function compareDottedVersion(v1, v2) {
+  var parts1 = /([0-9\.]+)(.*)$/.exec(v1);
+  var parts2 = /([0-9\.]+)(.*)$/.exec(v2);
+  if (parts1 != null && parts2 != null) {
+    var numbers1 = parts1[1];
+    var numbers2 = parts2[1];
+    var distinguisher1 = parts1[2];
+    var distinguisher2 = parts2[2];
+    var numlist1 = numbers1.split('.').map(function(e) { return +e; });
+    var numlist2 = numbers2.split('.').map(function(e) { return +e; });
+    var cmp = listCompare(numlist1, numlist2);
+    if (cmp !== 0) { return cmp; }
+    else { return distinguisher1 < distinguisher2? -1:
+                  distinguisher1 > distinguisher2? 1: 0; }
+  }
+  return v1 < v2? -1: v1 > v2? 1: 0;
+}
diff --git a/server.js b/server.js
index 88af91f8c4365..fefac6595e77a 100644
--- a/server.js
+++ b/server.js
@@ -38,6 +38,25 @@ if (serverSecrets && serverSecrets.gh_client_id) {
   githubAuth.setRoutes(camp);
 }
 
+const {latest: latestVersion} = require('./lib/version.js');
+const {
+  compare: phpVersionCompare,
+  latest: phpLatestVersion,
+  isStable: phpStableVersion,
+} = require('./lib/php-version.js');
+const {
+  currencyFromCode,
+  metric,
+  ordinalNumber,
+  starRating,
+} = require('./lib/text-formatters.js');
+const {
+  coveragePercentage: coveragePercentageColor,
+  downloadCount: downloadCountColor,
+  floorCount: floorCountColor,
+  version: versionColor,
+} = require('./lib/color-formatters.js');
+
 var semver = require('semver');
 var serverStartTime = new Date((new Date()).toGMTString());
 
@@ -6276,23 +6295,6 @@ function regularUpdate(url, interval, scraper, cb) {
   });
 }
 
-// Given a number, string with appropriate unit in the metric system, SI.
-// Note: numbers beyond the peta- cannot be represented as integers in JS.
-var metricPrefix = ['k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'];
-var metricPower = metricPrefix
-    .map(function(a, i) { return Math.pow(1000, i + 1); });
-function metric(n) {
-  for (var i = metricPrefix.length - 1; i >= 0; i--) {
-    var limit = metricPower[i];
-    if (n >= limit) {
-      n = Math.round(n / limit);
-      return ''+n + metricPrefix[i];
-    }
-  }
-  return ''+n;
-}
-
-
 // Get data from a svg-style badge.
 // cb: function(err, string)
 function fetchFromSvg(request, url, cb) {
@@ -6308,295 +6310,3 @@ function fetchFromSvg(request, url, cb) {
     }
   });
 }
-
-function ordinalNumber(n) {
-  var s=["ᵗʰ","ˢᵗ","ⁿᵈ","ʳᵈ"], v=n%100;
-  return n+(s[(v-20)%10]||s[v]||s[0]);
-}
-
-// Convert ISO 4217 code to unicode string.
-function currencyFromCode(code) {
-  return ({
-    CNY: '¥',
-    EUR: '€',
-    GBP: '₤',
-    USD: '$',
-  })[code] || code;
-}
-
-function starRating(rating) {
-  var stars = '';
-  while (stars.length < rating) { stars += '★'; }
-  while (stars.length < 5) { stars += '☆'; }
-  return stars;
-}
-
-function coveragePercentageColor(percentage) {
-  return floorCountColor(percentage, 80, 90, 100);
-}
-
-function downloadCountColor(downloads) {
-  return floorCountColor(downloads, 10, 100, 1000);
-}
-
-function floorCountColor(value, yellow, yellowgreen, green) {
-  if (value === 0) {
-    return 'red';
-  } else if (value < yellow) {
-    return 'yellow';
-  } else if (value < yellowgreen) {
-    return 'yellowgreen';
-  } else if (value < green) {
-    return 'green';
-  } else {
-    return 'brightgreen';
-  }
-}
-
-function versionColor(version) {
-  var first = version[0];
-  if (first === 'v') {
-    first = version[1];
-  } else if (/^[0-9]/.test(version)) {
-    version = 'v' + version;
-  }
-  if (first === '0' || (version.indexOf('-') !== -1)) {
-    return { version: version, color: 'orange' };
-  } else {
-    return { version: version, color: 'blue' };
-  }
-}
-
-// Take string versions.
-// -1 if v1 < v2, 1 if v1 > v2, 0 otherwise.
-function compareDottedVersion(v1, v2) {
-  var parts1 = /([0-9\.]+)(.*)$/.exec(v1);
-  var parts2 = /([0-9\.]+)(.*)$/.exec(v2);
-  if (parts1 != null && parts2 != null) {
-    var numbers1 = parts1[1];
-    var numbers2 = parts2[1];
-    var distinguisher1 = parts1[2];
-    var distinguisher2 = parts2[2];
-    var numlist1 = numbers1.split('.').map(function(e) { return +e; });
-    var numlist2 = numbers2.split('.').map(function(e) { return +e; });
-    var cmp = listCompare(numlist1, numlist2);
-    if (cmp !== 0) { return cmp; }
-    else { return distinguisher1 < distinguisher2? -1:
-                  distinguisher1 > distinguisher2? 1: 0; }
-  }
-  return v1 < v2? -1: v1 > v2? 1: 0;
-}
-
-// Take a list of string versions.
-// Return the latest, or undefined, if there are none.
-function latestDottedVersion(versions) {
-  var len = versions.length;
-  if (len === 0) { return; }
-  var version = versions[0];
-  for (var i = 1; i < len; i++) {
-    if (compareDottedVersion(version, versions[i]) < 0) {
-      version = versions[i];
-    }
-  }
-  return version;
-}
-
-// Given a list of versions (as strings), return the latest version.
-// Return undefined if no version could be found.
-function latestVersion(versions) {
-  var version = '';
-  var origVersions = versions;
-  versions = versions.filter(function(version) {
-    return (/^v?[0-9]/).test(version);
-  });
-  try {
-    version = semver.maxSatisfying(versions, '');
-  } catch(e) {
-    version = latestDottedVersion(versions);
-  }
-  if (version === undefined) {
-    origVersions = origVersions.sort();
-    version = origVersions[origVersions.length - 1];
-  }
-  return version;
-}
-
-// Return a negative value if v1 < v2,
-// zero if v1 = v2, a positive value otherwise.
-function asciiVersionCompare(v1, v2) {
-  if (v1 < v2) {
-    return -1;
-  } else if (v1 > v2) {
-    return 1;
-  } else {
-    return 0;
-  }
-}
-
-// Remove the starting v in a string.
-function omitv(version) {
-  if (version.charCodeAt(0) === 118) { // v
-    return version.slice(1);
-  } else {
-    return version;
-  }
-}
-
-// Take a version without the starting v.
-// eg, '1.0.x-beta'
-// Return { numbers: [1,0,something big], modifier: 2, modifierCount: 1 }
-function phpNumberedVersionData(version) {
-  // A version has a numbered part and a modifier part
-  // (eg, 1.0.0-patch, 2.0.x-dev).
-  var parts = version.split('-');
-  var numbered = parts[0];
-
-  // Aliases that get caught here.
-  if (numbered === 'dev') {
-    return {
-      numbers: parts[1],
-      modifier: 5,
-      modifierCount: 1,
-    };
-  }
-
-  var modifierLevel = 3;
-  var modifierLevelCount = 0;
-
-  if (parts.length > 1) {
-    var modifier = parts[parts.length - 1];
-    var firstLetter = modifier.charCodeAt(0);
-    var modifierLevelCountString;
-
-    // Modifiers: alpha < beta < RC < normal < patch < dev
-    if (firstLetter === 97) { // a
-      modifierLevel = 0;
-      if (/^alpha/.test(modifier)) {
-        modifierLevelCountString = + (modifier.slice(5));
-      } else {
-        modifierLevelCountString = + (modifier.slice(1));
-      }
-    } else if (firstLetter === 98) { // b
-      modifierLevel = 1;
-      if (/^beta/.test(modifier)) {
-        modifierLevelCountString = + (modifier.slice(4));
-      } else {
-        modifierLevelCountString = + (modifier.slice(1));
-      }
-    } else if (firstLetter === 82) { // R
-      modifierLevel = 2;
-      modifierLevelCountString = + (modifier.slice(2));
-    } else if (firstLetter === 112) { // p
-      modifierLevel = 4;
-      if (/^patch/.test(modifier)) {
-        modifierLevelCountString = + (modifier.slice(5));
-      } else {
-        modifierLevelCountString = + (modifier.slice(1));
-      }
-    } else if (firstLetter === 100) { // d
-      modifierLevel = 5;
-      if (/^dev/.test(modifier)) {
-        modifierLevelCountString = + (modifier.slice(3));
-      } else {
-        modifierLevelCountString = + (modifier.slice(1));
-      }
-    }
-
-    // If we got the empty string, it defaults to a modifier count of 1.
-    if (!modifierLevelCountString) {
-      modifierLevelCount = 1;
-    } else {
-      modifierLevelCount = + modifierLevelCountString;
-    }
-  }
-
-  // Try to convert to a list of numbers.
-  var toNum = function(s) {
-    var n = +s;
-    if (n !== n) {  // If n is NaN…
-      n = 0xffffffff;
-    }
-    return n;
-  };
-  var numberList = numbered.split('.').map(toNum);
-
-  return {
-    numbers: numberList,
-    modifier: modifierLevel,
-    modifierCount: modifierLevelCount,
-  };
-}
-
-function listCompare(a, b) {
-  var alen = a.length, blen = b.length;
-  for (var i = 0; i < alen; i++) {
-    if (a[i] < b[i]) {
-      return -1;
-    } else if (a[i] > b[i]) {
-      return 1;
-    }
-  }
-  return alen - blen;
-}
-
-// Return a negative value if v1 < v2,
-// zero if v1 = v2,
-// a positive value otherwise.
-//
-// See https://getcomposer.org/doc/04-schema.md#version
-// and https://github.com/badges/shields/issues/319#issuecomment-74411045
-function phpVersionCompare(v1, v2) {
-  // Omit the starting `v`.
-  var rawv1 = omitv(v1);
-  var rawv2 = omitv(v2);
-  try {
-    var v1data = phpNumberedVersionData(rawv1);
-    var v2data = phpNumberedVersionData(rawv2);
-  } catch(e) {
-    return asciiVersionCompare(rawv1, rawv2);
-  }
-
-  // Compare the numbered part (eg, 1.0.0 < 2.0.0).
-  var numbersCompare = listCompare(v1data.numbers, v2data.numbers);
-  if (numbersCompare !== 0) {
-    return numbersCompare;
-  }
-
-  // Compare the modifiers (eg, alpha < beta).
-  if (v1data.modifier < v2data.modifier) {
-    return -1;
-  } else if (v1data.modifier > v2data.modifier) {
-    return 1;
-  }
-
-  // Compare the modifier counts (eg, alpha1 < alpha3).
-  if (v1data.modifierCount < v2data.modifierCount) {
-    return -1;
-  } else if (v1data.modifierCount > v2data.modifierCount) {
-    return 1;
-  }
-
-  return 0;
-}
-
-function phpLatestVersion(versions) {
-  var latest = versions[0];
-  for (var i = 1; i < versions.length; i++) {
-    if (phpVersionCompare(latest, versions[i]) < 0) {
-      latest = versions[i];
-    }
-  }
-  return latest;
-}
-
-// Whether a version is stable.
-function phpStableVersion(version) {
-  var rawVersion = omitv(version);
-  try {
-    var versionData = phpNumberedVersionData(rawVersion);
-  } catch(e) {
-    return false;
-  }
-  // normal or patch
-  return (versionData.modifier === 3) || (versionData.modifier === 4);
-}