diff --git a/lib/modules/manager/mix/__fixtures__/mix.exs b/lib/modules/manager/mix/__fixtures__/mix.exs
index 9bc2b75a800d38d2c08c39cebebf8c3561a2ee8a..2ad51c305e58e17627d59bea32232cf48b924231 100644
--- a/lib/modules/manager/mix/__fixtures__/mix.exs
+++ b/lib/modules/manager/mix/__fixtures__/mix.exs
@@ -27,13 +27,19 @@ defmodule MyProject.MixProject do
       {:secret, "~> 1.0", organization: "acme"},
       {:also_secret, "~> 1.0", only: [:dev, :test], organization: "acme", runtime: false},
       {:metrics, ">0.2.0 and <=1.0.0"},
-      {:jason, ">= 1.0.0"},
+      {:jason, ">= 1.0.0", only: :prod},
       {:hackney, "~> 1.0",
         optional: true},
-      {:hammer_backend_redis, "~> 6.1"},
+      {:hammer_backend_redis, "~> 6.1", only: [:dev, :prod, :test]},
       {:castore, "== 1.0.10"},
       {:gun, "~> 2.0.0", hex: "grpc_gun"},
       {:another_gun, "~> 0.4.0", hex: :raygun},
+      {:credo, "~> 1.7", only:
+        [:test,
+        # prod,
+        :dev],
+        runtime: false},
+      {:floki, "== 0.37.0", only: :test},
     ]
   end
 end
diff --git a/lib/modules/manager/mix/__fixtures__/mix.lock b/lib/modules/manager/mix/__fixtures__/mix.lock
index d90b44ee2d1c3824748880ed9eaf81df687dded4..106d497cd6b91e606cb3cfd02c1082665bbace5b 100644
--- a/lib/modules/manager/mix/__fixtures__/mix.lock
+++ b/lib/modules/manager/mix/__fixtures__/mix.lock
@@ -1,13 +1,17 @@
 %{
   "another_gun": {:hex, :raygun, "0.4.0", "7744e99dd695f61e78ad5e047cce0affb3edfc6f93a92278598ab553b9c5091f", [:mix], [{:httpoison, "~> 0.8 or ~> 1.0", [hex: :httpoison, repo: "hexpm", optional: false]}, {:jason, "~> 1.2", [hex: :jason, repo: "hexpm", optional: false]}, {:plug, "~> 1.1", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm", "eee4b891e6e65c6a4b15386dc7b7a72b717f3c123cc0012cfd19e8f2ab21116d"},
+  "bunt": {:hex, :bunt, "1.0.0", "081c2c665f086849e6d57900292b3a161727ab40431219529f13c4ddcf3e7a44", [:mix], [], "hexpm", "dc5f86aa08a5f6fa6b8096f0735c4e76d54ae5c9fa2c143e5a1fc7c1cd9bb6b5"},
   "castore": {:hex, :castore, "1.0.10", "43bbeeac820f16c89f79721af1b3e092399b3a1ecc8df1a472738fd853574911", [:mix], [], "hexpm", "1b0b7ea14d889d9ea21202c43a4fa015eb913021cb535e8ed91946f4b77a8848"},
   "certifi": {:hex, :certifi, "2.12.0", "2d1cca2ec95f59643862af91f001478c9863c2ac9cb6e2f89780bfd8de987329", [:rebar3], [], "hexpm", "ee68d85df22e554040cdb4be100f33873ac6051387baf6a8f6ce82272340ff1c"},
   "cowboy": {:git, "https://github.com/ninenines/cowboy.git", "0c2e2224e372f01e6cf51a8e12d4856edb4cb8ac", [tag: "0.6.0"]},
   "cowlib": {:hex, :cowlib, "2.13.0", "db8f7505d8332d98ef50a3ef34b34c1afddec7506e4ee4dd4a3a266285d282ca", [:make, :rebar3], [], "hexpm", "e1e1284dc3fc030a64b1ad0d8382ae7e99da46c3246b815318a4b848873800a4"},
+  "credo": {:hex, :credo, "1.7.10", "6e64fe59be8da5e30a1b96273b247b5cf1cc9e336b5fd66302a64b25749ad44d", [:mix], [{:bunt, "~> 0.2.1 or ~> 1.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "71fbc9a6b8be21d993deca85bf151df023a3097b01e09a2809d460348561d8cd"},
   "decimal": {:hex, :decimal, "1.9.0", "83e8daf59631d632b171faabafb4a9f4242c514b0a06ba3df493951c08f64d07", [:mix], [], "hexpm", "b1f2343568eed6928f3e751cf2dffde95bfaa19dd95d09e8a9ea92ccfd6f7d85"},
   "ecto": {:git, "https://github.com/elixir-ecto/ecto.git", "795036d997c7503b21fb64d6bf1a89b83c44f2b5", [ref: "795036d997c7503b21fb64d6bf1a89b83c44f2b5"]},
   "secret": {:hex, :secret, "1.5.0", "344dbbf6610d205760ec37e2848bff2aab5a2de182bb5cdaa72cc2fd19d74535", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: false]}], "hexpm", "19c205c8de0e2e5817f2250100281c58e717cb11ff1bb410bf661ee78c24e79b"},
   "also_secret": {:hex, :also_secret, "1.3.4", "344dbbf6610d205760ec37e2848bff2aab5a2de182bb5cdaa72cc2fd19d74535", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: false]}], "hexpm", "19c205c8de0e2e5817f2250100281c58e717cb11ff1bb410bf661ee78c24e79b"},
+  "file_system": {:hex, :file_system, "1.0.1", "79e8ceaddb0416f8b8cd02a0127bdbababe7bf4a23d2a395b983c1f8b3f73edd", [:mix], [], "hexpm", "4414d1f38863ddf9120720cd976fce5bdde8e91d8283353f0e31850fa89feb9e"},
+  "floki": {:hex, :floki, "0.37.0", "b83e0280bbc6372f2a403b2848013650b16640cd2470aea6701f0632223d719e", [:mix], [], "hexpm", "516a0c15a69f78c47dc8e0b9b3724b29608aa6619379f91b1ffa47109b5d0dd3"},
   "gun": {:hex, :grpc_gun, "2.0.1", "221b792df3a93e8fead96f697cbaf920120deacced85c6cd3329d2e67f0871f8", [:rebar3], [{:cowlib, "~> 2.11", [hex: :cowlib, repo: "hexpm", optional: false]}], "hexpm", "795a65eb9d0ba16697e6b0e1886009ce024799e43bb42753f0c59b029f592831"},
   "hackney": {:hex, :hackney, "1.20.1", "8d97aec62ddddd757d128bfd1df6c5861093419f8f7a4223823537bad5d064e2", [:rebar3], [{:certifi, "~> 2.12.0", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "~> 6.1.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "~> 1.0.0", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~> 1.1", [hex: :mimerl, repo: "hexpm", optional: false]}, {:parse_trans, "3.4.1", [hex: :parse_trans, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "~> 1.1.0", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}, {:unicode_util_compat, "~> 0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "fe9094e5f1a2a2c0a7d10918fee36bfec0ec2a979994cff8cfe8058cd9af38e3"},
   "hammer": {:hex, :hammer, "6.2.1", "5ae9c33e3dceaeb42de0db46bf505bd9c35f259c8defb03390cd7556fea67ee2", [:mix], [{:poolboy, "~> 1.5", [hex: :poolboy, repo: "hexpm", optional: false]}], "hexpm", "b9476d0c13883d2dc0cc72e786bac6ac28911fba7cc2e04b70ce6a6d9c4b2bdc"},
diff --git a/lib/modules/manager/mix/extract.spec.ts b/lib/modules/manager/mix/extract.spec.ts
index 3663073aabc20c6846ac741501b0405acd194378..a20ea0327fd715d6798b89de6018b5b34e71e4c7 100644
--- a/lib/modules/manager/mix/extract.spec.ts
+++ b/lib/modules/manager/mix/extract.spec.ts
@@ -20,12 +20,14 @@ describe('modules/manager/mix/extract', () => {
           currentValue: '~> 0.8.1',
           datasource: 'hex',
           depName: 'postgrex',
+          depType: 'prod',
           packageName: 'postgrex',
         },
         {
           currentValue: '<1.7.0 or ~>1.7.1',
           datasource: 'hex',
           depName: 'ranch',
+          depType: 'prod',
           packageName: 'ranch',
         },
         {
@@ -33,6 +35,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: '0.6.0',
           datasource: 'github-tags',
           depName: 'cowboy',
+          depType: 'prod',
           packageName: 'ninenines/cowboy',
         },
         {
@@ -40,6 +43,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: 'main',
           datasource: 'git-tags',
           depName: 'phoenix',
+          depType: 'prod',
           packageName: 'https://github.com/phoenixframework/phoenix.git',
         },
         {
@@ -47,42 +51,49 @@ describe('modules/manager/mix/extract', () => {
           currentValue: undefined,
           datasource: 'github-tags',
           depName: 'ecto',
+          depType: 'prod',
           packageName: 'elixir-ecto/ecto',
         },
         {
           currentValue: '~> 1.0',
           datasource: 'hex',
           depName: 'secret',
+          depType: 'prod',
           packageName: 'secret:acme',
         },
         {
           currentValue: '~> 1.0',
           datasource: 'hex',
           depName: 'also_secret',
+          depType: 'dev',
           packageName: 'also_secret:acme',
         },
         {
           currentValue: '>0.2.0 and <=1.0.0',
           datasource: 'hex',
           depName: 'metrics',
+          depType: 'prod',
           packageName: 'metrics',
         },
         {
           currentValue: '>= 1.0.0',
           datasource: 'hex',
           depName: 'jason',
+          depType: 'prod',
           packageName: 'jason',
         },
         {
           currentValue: '~> 1.0',
           datasource: 'hex',
           depName: 'hackney',
+          depType: 'prod',
           packageName: 'hackney',
         },
         {
           currentValue: '~> 6.1',
           datasource: 'hex',
           depName: 'hammer_backend_redis',
+          depType: 'prod',
           packageName: 'hammer_backend_redis',
         },
         {
@@ -90,20 +101,38 @@ describe('modules/manager/mix/extract', () => {
           currentVersion: '1.0.10',
           datasource: 'hex',
           depName: 'castore',
+          depType: 'prod',
           packageName: 'castore',
         },
         {
           currentValue: '~> 2.0.0',
           datasource: 'hex',
           depName: 'gun',
+          depType: 'prod',
           packageName: 'grpc_gun',
         },
         {
           currentValue: '~> 0.4.0',
           datasource: 'hex',
           depName: 'another_gun',
+          depType: 'prod',
           packageName: 'raygun',
         },
+        {
+          currentValue: '~> 1.7',
+          datasource: 'hex',
+          depName: 'credo',
+          depType: 'dev',
+          packageName: 'credo',
+        },
+        {
+          currentValue: '== 0.37.0',
+          currentVersion: '0.37.0',
+          datasource: 'hex',
+          depName: 'floki',
+          depType: 'dev',
+          packageName: 'floki',
+        },
       ]);
     });
 
@@ -116,6 +145,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: '~> 0.8.1',
           datasource: 'hex',
           depName: 'postgrex',
+          depType: 'prod',
           packageName: 'postgrex',
           lockedVersion: '0.8.4',
         },
@@ -123,6 +153,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: '<1.7.0 or ~>1.7.1',
           datasource: 'hex',
           depName: 'ranch',
+          depType: 'prod',
           packageName: 'ranch',
           lockedVersion: '1.7.1',
         },
@@ -131,6 +162,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: '0.6.0',
           datasource: 'github-tags',
           depName: 'cowboy',
+          depType: 'prod',
           packageName: 'ninenines/cowboy',
           lockedVersion: '0.6.0',
         },
@@ -139,6 +171,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: 'main',
           datasource: 'git-tags',
           depName: 'phoenix',
+          depType: 'prod',
           packageName: 'https://github.com/phoenixframework/phoenix.git',
           lockedVersion: undefined,
         },
@@ -147,6 +180,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: undefined,
           datasource: 'github-tags',
           depName: 'ecto',
+          depType: 'prod',
           packageName: 'elixir-ecto/ecto',
           lockedVersion: undefined,
         },
@@ -154,6 +188,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: '~> 1.0',
           datasource: 'hex',
           depName: 'secret',
+          depType: 'prod',
           packageName: 'secret:acme',
           lockedVersion: '1.5.0',
         },
@@ -161,6 +196,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: '~> 1.0',
           datasource: 'hex',
           depName: 'also_secret',
+          depType: 'dev',
           packageName: 'also_secret:acme',
           lockedVersion: '1.3.4',
         },
@@ -168,6 +204,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: '>0.2.0 and <=1.0.0',
           datasource: 'hex',
           depName: 'metrics',
+          depType: 'prod',
           packageName: 'metrics',
           lockedVersion: '1.0.0',
         },
@@ -175,6 +212,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: '>= 1.0.0',
           datasource: 'hex',
           depName: 'jason',
+          depType: 'prod',
           packageName: 'jason',
           lockedVersion: '1.4.4',
         },
@@ -182,6 +220,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: '~> 1.0',
           datasource: 'hex',
           depName: 'hackney',
+          depType: 'prod',
           packageName: 'hackney',
           lockedVersion: '1.20.1',
         },
@@ -189,6 +228,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: '~> 6.1',
           datasource: 'hex',
           depName: 'hammer_backend_redis',
+          depType: 'prod',
           packageName: 'hammer_backend_redis',
           lockedVersion: '6.2.0',
         },
@@ -197,6 +237,7 @@ describe('modules/manager/mix/extract', () => {
           currentVersion: '1.0.10',
           datasource: 'hex',
           depName: 'castore',
+          depType: 'prod',
           packageName: 'castore',
           lockedVersion: '1.0.10',
         },
@@ -204,6 +245,7 @@ describe('modules/manager/mix/extract', () => {
           currentValue: '~> 2.0.0',
           datasource: 'hex',
           depName: 'gun',
+          depType: 'prod',
           packageName: 'grpc_gun',
           lockedVersion: '2.0.1',
         },
@@ -211,9 +253,27 @@ describe('modules/manager/mix/extract', () => {
           currentValue: '~> 0.4.0',
           datasource: 'hex',
           depName: 'another_gun',
+          depType: 'prod',
           packageName: 'raygun',
           lockedVersion: '0.4.0',
         },
+        {
+          currentValue: '~> 1.7',
+          datasource: 'hex',
+          depName: 'credo',
+          depType: 'dev',
+          packageName: 'credo',
+          lockedVersion: '1.7.10',
+        },
+        {
+          currentValue: '== 0.37.0',
+          currentVersion: '0.37.0',
+          datasource: 'hex',
+          depName: 'floki',
+          depType: 'dev',
+          lockedVersion: '0.37.0',
+          packageName: 'floki',
+        },
       ]);
     });
   });
diff --git a/lib/modules/manager/mix/extract.ts b/lib/modules/manager/mix/extract.ts
index 3d9c45e00d74f4f90ac48d7938d4189ae46d20ed..9d8c5a90b6539213088b4d9f3df04517841e5af8 100644
--- a/lib/modules/manager/mix/extract.ts
+++ b/lib/modules/manager/mix/extract.ts
@@ -20,6 +20,8 @@ const lockedVersionRegExp = regEx(
   /^\s+"(?<app>\w+)".*?"(?<lockedVersion>\d+\.\d+\.\d+)"/,
 );
 const hexRegexp = regEx(/hex:\s*(?:"(?<strValue>[^"]+)"|:(?<atomValue>\w+))/);
+const onlyValueRegexp = regEx(/only:\s*(?<only>\[[^\]]*\]|:\w+)/);
+const onlyEnvironmentsRegexp = regEx(/:(\w+)/gm);
 
 export async function extractPackageFile(
   content: string,
@@ -48,22 +50,28 @@ export async function extractPackageFile(
         const hexGroups = hexRegexp.exec(opts)?.groups;
         const hex = hexGroups?.strValue ?? hexGroups?.atomValue;
 
-        let dep: PackageDependency;
+        const onlyValue = onlyValueRegexp.exec(opts)?.groups?.only;
+        const onlyEnvironments = [];
+        let match;
+        if (onlyValue) {
+          while ((match = onlyEnvironmentsRegexp.exec(onlyValue)) !== null) {
+            onlyEnvironments.push(match[1]);
+          }
+        }
+
+        const dep: PackageDependency = {
+          depName: app,
+          depType: 'prod',
+        };
 
         if (git ?? github) {
-          dep = {
-            depName: app,
-            currentDigest: ref,
-            currentValue: branchOrTag,
-            datasource: git ? GitTagsDatasource.id : GithubTagsDatasource.id,
-            packageName: git ?? github,
-          };
+          dep.currentDigest = ref;
+          dep.currentValue = branchOrTag;
+          dep.datasource = git ? GitTagsDatasource.id : GithubTagsDatasource.id;
+          dep.packageName = git ?? github;
         } else {
-          dep = {
-            depName: app,
-            currentValue: requirement,
-            datasource: HexDatasource.id,
-          };
+          dep.currentValue = requirement;
+          dep.datasource = HexDatasource.id;
           if (organization) {
             dep.packageName = `${app}:${organization}`;
           } else if (hex) {
@@ -71,11 +79,16 @@ export async function extractPackageFile(
           } else {
             dep.packageName = app;
           }
+
           if (requirement?.startsWith('==')) {
             dep.currentVersion = requirement.replace(regEx(/^==\s*/), '');
           }
         }
 
+        if (onlyValue !== undefined && !onlyEnvironments.includes('prod')) {
+          dep.depType = 'dev';
+        }
+
         deps.set(app, dep);
         logger.trace({ dep }, `setting ${app}`);
         depMatchGroups = depMatchRegExp.exec(depBuffer)?.groups;
diff --git a/lib/modules/manager/mix/readme.md b/lib/modules/manager/mix/readme.md
index f63ab44019224e3466343733021d45aa18a5a1e4..175d75a90031231febaa96a1737d7cb82a882d44 100644
--- a/lib/modules/manager/mix/readme.md
+++ b/lib/modules/manager/mix/readme.md
@@ -1,3 +1,8 @@
-The `mix` manager extracts dependencies for the `hex` datasource and uses Renovate's implementation of Hex SemVer to evaluate updates.
+The `mix` manager uses Renovate's implementation of [Elixir SemVer](https://hexdocs.pm/elixir/Version.html#module-requirements) to evaluate update ranges.
 
-The `mix` package manager itself is also used to keep the lock file up-to-date.
+The `mix` package manager itself is used to keep the lock file up-to-date.
+
+The following `depTypes` are currently supported by the `mix` manager :
+
+- `prod`: all dependencies by default
+- `dev`: dependencies with [`:only` option](https://hexdocs.pm/mix/Mix.Tasks.Deps.html#module-dependency-definition-options) not containing `:prod`