diff --git a/Library/Homebrew/brew.rb b/Library/Homebrew/brew.rb
index 41120b0b04..27b78a0acd 100644
--- a/Library/Homebrew/brew.rb
+++ b/Library/Homebrew/brew.rb
@@ -107,6 +107,24 @@ begin
     end
   end
 
+  developer_mode = if cmd == "developer" && ARGV.include?("on")
+    true
+  elsif cmd == "developer" && ARGV.include?("off")
+    false
+  else
+    Homebrew::EnvConfig.developer? || Homebrew::Settings.read("devcmdrun") == "true"
+  end
+
+  if internal_dev_cmd && Homebrew::EnvConfig.install_from_api?
+    odie "Developer commands cannot be run while HOMEBREW_INSTALL_FROM_API is set!"
+  elsif Homebrew::EnvConfig.install_from_api? && developer_mode
+    opoo <<~MESSAGE
+      Developers should not have HOMEBREW_INSTALL_FROM_API set!
+      Please unset HOMEBREW_INSTALL_FROM_API or turn developer mode off by running:
+        brew developer off
+    MESSAGE
+  end
+
   unless internal_cmd
     # Add contributed commands to PATH before checking.
     homebrew_path.append(Tap.cmd_directories)
diff --git a/Library/Homebrew/cask/cask.rb b/Library/Homebrew/cask/cask.rb
index bf274ec823..616a7bff43 100644
--- a/Library/Homebrew/cask/cask.rb
+++ b/Library/Homebrew/cask/cask.rb
@@ -149,7 +149,7 @@ module Cask
         return []
       end
 
-      latest_version = if ENV["HOMEBREW_INSTALL_FROM_API"].present? &&
+      latest_version = if Homebrew::EnvConfig.install_from_api? &&
                           (latest_cask_version = Homebrew::API::Versions.latest_cask_version(token))
         DSL::Version.new latest_cask_version.to_s
       else
diff --git a/Library/Homebrew/cli/named_args.rb b/Library/Homebrew/cli/named_args.rb
index 9a53f77cb5..bab7899a98 100644
--- a/Library/Homebrew/cli/named_args.rb
+++ b/Library/Homebrew/cli/named_args.rb
@@ -94,7 +94,7 @@ module Homebrew
         unreadable_error = nil
 
         if only != :cask
-          if prefer_loading_from_api && ENV["HOMEBREW_INSTALL_FROM_API"].present? &&
+          if prefer_loading_from_api && Homebrew::EnvConfig.install_from_api? &&
              Homebrew::API::Bottle.available?(name)
             Homebrew::API::Bottle.fetch_bottles(name)
           end
@@ -132,7 +132,7 @@ module Homebrew
         end
 
         if only != :formula
-          if prefer_loading_from_api && ENV["HOMEBREW_INSTALL_FROM_API"].present? &&
+          if prefer_loading_from_api && Homebrew::EnvConfig.install_from_api? &&
              Homebrew::API::CaskSource.available?(name)
             contents = Homebrew::API::CaskSource.fetch(name)
           end
diff --git a/Library/Homebrew/cmd/info.rb b/Library/Homebrew/cmd/info.rb
index bcba02b574..0c36d9b9d0 100644
--- a/Library/Homebrew/cmd/info.rb
+++ b/Library/Homebrew/cmd/info.rb
@@ -252,7 +252,7 @@ module Homebrew
   def info_formula(f, args:)
     specs = []
 
-    if ENV["HOMEBREW_INSTALL_FROM_API"].present? && Homebrew::API::Bottle.available?(f.name)
+    if Homebrew::EnvConfig.install_from_api? && Homebrew::API::Bottle.available?(f.name)
       info = Homebrew::API::Bottle.fetch(f.name)
 
       latest_version = info["pkg_version"].split("_").first
diff --git a/Library/Homebrew/cmd/outdated.rb b/Library/Homebrew/cmd/outdated.rb
index 17f52b1f68..80013e1856 100644
--- a/Library/Homebrew/cmd/outdated.rb
+++ b/Library/Homebrew/cmd/outdated.rb
@@ -98,7 +98,7 @@ module Homebrew
         if verbose?
           outdated_kegs = f.outdated_kegs(fetch_head: args.fetch_HEAD?)
 
-          current_version = if !f.head? && ENV["HOMEBREW_INSTALL_FROM_API"].present? &&
+          current_version = if !f.head? && Homebrew::EnvConfig.install_from_api? &&
                                (f.core_formula? || f.tap.blank?)
             Homebrew::API::Versions.latest_formula_version(f.name)&.to_s || f.pkg_version.to_s
           elsif f.alias_changed? && !f.latest_formula.latest_version_installed?
diff --git a/Library/Homebrew/cmd/reinstall.rb b/Library/Homebrew/cmd/reinstall.rb
index 08e197b5e3..c29675f3f7 100644
--- a/Library/Homebrew/cmd/reinstall.rb
+++ b/Library/Homebrew/cmd/reinstall.rb
@@ -88,7 +88,7 @@ module Homebrew
     # We need to use the bottle API instead of just using the formula file
     # from an installed keg because it will not contain bottle information.
     # As a consequence, `brew reinstall` will also upgrade outdated formulae
-    if ENV["HOMEBREW_INSTALL_FROM_API"].present?
+    if Homebrew::EnvConfig.install_from_api?
       args.named.each do |name|
         formula = Formulary.factory(name)
         next unless formula.any_version_installed?
diff --git a/Library/Homebrew/cmd/untap.rb b/Library/Homebrew/cmd/untap.rb
index 6e076bba81..3c51d60dfa 100644
--- a/Library/Homebrew/cmd/untap.rb
+++ b/Library/Homebrew/cmd/untap.rb
@@ -25,7 +25,7 @@ module Homebrew
     args = untap_args.parse
 
     args.named.to_installed_taps.each do |tap|
-      odie "Untapping #{tap} is not allowed" if tap.core_tap? && ENV["HOMEBREW_INSTALL_FROM_API"].blank?
+      odie "Untapping #{tap} is not allowed" if tap.core_tap? && !Homebrew::EnvConfig.install_from_api?
 
       installed_tap_formulae = Formula.installed.select { |formula| formula.tap == tap }
       installed_tap_casks = Cask::Caskroom.casks.select { |cask| cask.tap == tap }
diff --git a/Library/Homebrew/cmd/update-report.rb b/Library/Homebrew/cmd/update-report.rb
index 49fa06d917..15baa2695f 100644
--- a/Library/Homebrew/cmd/update-report.rb
+++ b/Library/Homebrew/cmd/update-report.rb
@@ -136,9 +136,7 @@ module Homebrew
     updated_taps = []
     Tap.each do |tap|
       next unless tap.git?
-      if (tap.core_tap? || tap == "homebrew/cask") && ENV["HOMEBREW_INSTALL_FROM_API"].present? && args.preinstall?
-        next
-      end
+      next if (tap.core_tap? || tap == "homebrew/cask") && Homebrew::EnvConfig.install_from_api? && args.preinstall?
 
       if ENV["HOMEBREW_MIGRATE_LINUXBREW_FORMULAE"].present? && tap.core_tap? &&
          Settings.read("linuxbrewmigrated") != "true"
@@ -266,7 +264,7 @@ module Homebrew
 
   def install_core_tap_if_necessary
     return if ENV["HOMEBREW_UPDATE_TEST"]
-    return if ENV["HOMEBREW_INSTALL_FROM_API"].present?
+    return if Homebrew::EnvConfig.install_from_api?
 
     core_tap = CoreTap.instance
     return if core_tap.installed?
diff --git a/Library/Homebrew/cmd/upgrade.rb b/Library/Homebrew/cmd/upgrade.rb
index aad5f5aa4a..6c4514acd1 100644
--- a/Library/Homebrew/cmd/upgrade.rb
+++ b/Library/Homebrew/cmd/upgrade.rb
@@ -158,7 +158,7 @@ module Homebrew
       puts pinned.map { |f| "#{f.full_specified_name} #{f.pkg_version}" } * ", "
     end
 
-    if ENV["HOMEBREW_INSTALL_FROM_API"].present?
+    if Homebrew::EnvConfig.install_from_api?
       formulae_to_install.map! do |formula|
         next formula if formula.head?
         next formula if formula.tap.present? && !formula.core_formula?
@@ -223,7 +223,7 @@ module Homebrew
   def upgrade_outdated_casks(casks, args:)
     return false if args.formula?
 
-    if ENV["HOMEBREW_INSTALL_FROM_API"].present?
+    if Homebrew::EnvConfig.install_from_api?
       casks = casks.map do |cask|
         next cask if cask.tap.present? && cask.tap != "homebrew/cask"
         next cask unless Homebrew::API::CaskSource.available?(cask.token)
diff --git a/Library/Homebrew/env_config.rb b/Library/Homebrew/env_config.rb
index 8d85b31197..b0039ae23f 100644
--- a/Library/Homebrew/env_config.rb
+++ b/Library/Homebrew/env_config.rb
@@ -189,6 +189,11 @@ module Homebrew
         default_text: 'The "Beer Mug" emoji.',
         default:      "🍺",
       },
+      HOMEBREW_INSTALL_FROM_API:               {
+        description: "If set, install formulae and casks in homebrew/core and homebrew/cask taps using Homebrew's " \
+                     "API instead of needing (large, slow) local checkouts of these repositories.",
+        boolean:     true,
+      },
       HOMEBREW_LIVECHECK_WATCHLIST:            {
         description: "Consult this file for the list of formulae to check by default when no formula argument " \
                      "is passed to `brew livecheck`.",
diff --git a/Library/Homebrew/extend/os/mac/tap.rb b/Library/Homebrew/extend/os/mac/tap.rb
index d88902a1d3..b6a9e7b63e 100644
--- a/Library/Homebrew/extend/os/mac/tap.rb
+++ b/Library/Homebrew/extend/os/mac/tap.rb
@@ -4,7 +4,7 @@
 class Tap
   def self.install_default_cask_tap_if_necessary(force: false)
     return false if default_cask_tap.installed?
-    return false if ENV["HOMEBREW_INSTALL_FROM_API"].present?
+    return false if Homebrew::EnvConfig.install_from_api?
     return false if !force && Tap.untapped_official_taps.include?(default_cask_tap.name)
 
     default_cask_tap.install
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 6573a85262..2c8a856e3a 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -529,7 +529,7 @@ class Formula
   # exists and is not empty.
   # @private
   def latest_version_installed?
-    latest_prefix = if !head? && ENV["HOMEBREW_INSTALL_FROM_API"].present? &&
+    latest_prefix = if !head? && Homebrew::EnvConfig.install_from_api? &&
                        (latest_pkg_version = Homebrew::API::Versions.latest_formula_version(name))
       prefix latest_pkg_version
     else
@@ -1349,7 +1349,7 @@ class Formula
     Formula.cache[:outdated_kegs][cache_key] ||= begin
       all_kegs = []
       current_version = T.let(false, T::Boolean)
-      latest_version = if !head? && ENV["HOMEBREW_INSTALL_FROM_API"].present? && (core_formula? || tap.blank?)
+      latest_version = if !head? && Homebrew::EnvConfig.install_from_api? && (core_formula? || tap.blank?)
         Homebrew::API::Versions.latest_formula_version(name) || pkg_version
       else
         pkg_version
diff --git a/Library/Homebrew/formulary.rb b/Library/Homebrew/formulary.rb
index dc88595f48..589fa5373b 100644
--- a/Library/Homebrew/formulary.rb
+++ b/Library/Homebrew/formulary.rb
@@ -361,7 +361,7 @@ module Formulary
     end
 
     def get_formula(*)
-      if !CoreTap.instance.installed? && ENV["HOMEBREW_INSTALL_FROM_API"].present?
+      if !CoreTap.instance.installed? && Homebrew::EnvConfig.install_from_api?
         raise CoreTapFormulaUnavailableError, name
       end
 
@@ -399,7 +399,7 @@ module Formulary
   )
     raise ArgumentError, "Formulae must have a ref!" unless ref
 
-    if ENV["HOMEBREW_INSTALL_FROM_API"].present? &&
+    if Homebrew::EnvConfig.install_from_api? &&
        @formula_name_local_bottle_path_map.present? &&
        @formula_name_local_bottle_path_map.key?(ref)
       ref = @formula_name_local_bottle_path_map[ref]
@@ -431,7 +431,7 @@ module Formulary
   # @param formula_name the formula name string to map.
   # @param local_bottle_path a path pointing to the target bottle archive.
   def self.map_formula_name_to_local_bottle_path(formula_name, local_bottle_path)
-    if ENV["HOMEBREW_INSTALL_FROM_API"].blank?
+    unless Homebrew::EnvConfig.install_from_api?
       raise UsageError, "HOMEBREW_INSTALL_FROM_API not set but required for #{__method__}!"
     end
 
diff --git a/Library/Homebrew/sorbet/rbi/hidden-definitions/hidden.rbi b/Library/Homebrew/sorbet/rbi/hidden-definitions/hidden.rbi
index fd59852672..2cd77dd314 100644
--- a/Library/Homebrew/sorbet/rbi/hidden-definitions/hidden.rbi
+++ b/Library/Homebrew/sorbet/rbi/hidden-definitions/hidden.rbi
@@ -4588,6 +4588,8 @@ module Homebrew::EnvConfig
 
   def self.install_badge(); end
 
+  def self.install_from_api?(); end
+
   def self.livecheck_watchlist(); end
 
   def self.logs(); end
diff --git a/Library/Homebrew/tap.rb b/Library/Homebrew/tap.rb
index 01eb2a37c4..671272713f 100644
--- a/Library/Homebrew/tap.rb
+++ b/Library/Homebrew/tap.rb
@@ -772,7 +772,7 @@ class CoreTap < Tap
 
   def self.ensure_installed!
     return if instance.installed?
-    return if ENV["HOMEBREW_INSTALL_FROM_API"].present?
+    return if Homebrew::EnvConfig.install_from_api?
 
     safe_system HOMEBREW_BREW_FILE, "tap", instance.name
   end
@@ -795,7 +795,7 @@ class CoreTap < Tap
   # @private
   sig { params(manual: T::Boolean).void }
   def uninstall(manual: false)
-    raise "Tap#uninstall is not available for CoreTap" if ENV["HOMEBREW_INSTALL_FROM_API"].blank?
+    raise "Tap#uninstall is not available for CoreTap" unless Homebrew::EnvConfig.install_from_api?
 
     super
   end
diff --git a/docs/Manpage.md b/docs/Manpage.md
index 53be4196d4..2a564d6bd1 100644
--- a/docs/Manpage.md
+++ b/docs/Manpage.md
@@ -2029,6 +2029,9 @@ example, run `export HOMEBREW_NO_INSECURE_REDIRECT=1` rather than just
 
   *Default:* The "Beer Mug" emoji.
 
+- `HOMEBREW_INSTALL_FROM_API`
+  <br>If set, install formulae and casks using Homebrew's formulae.brew.sh API instead of using local definitions. This allows formulae and casks in homebrew/core and homebrew/cask to be installed even if their respective tap is not installed locally.
+
 - `HOMEBREW_LIVECHECK_WATCHLIST`
   <br>Consult this file for the list of formulae to check by default when no formula argument is passed to `brew livecheck`.
 
diff --git a/manpages/brew.1 b/manpages/brew.1
index 41bcc00e10..dabd715357 100644
--- a/manpages/brew.1
+++ b/manpages/brew.1
@@ -2928,6 +2928,12 @@ Print this text before the installation summary of each successful build\.
 \fIDefault:\fR The "Beer Mug" emoji\.
 .
 .TP
+\fBHOMEBREW_INSTALL_FROM_API\fR
+.
+.br
+If set, install formulae and casks using Homebrew\'s formulae\.brew\.sh API instead of using local definitions\. This allows formulae and casks in homebrew/core and homebrew/cask to be installed even if their respective tap is not installed locally\.
+.
+.TP
 \fBHOMEBREW_LIVECHECK_WATCHLIST\fR
 .
 .br