diff --git a/modules/runtime-common/src/test/resources/config_parser_test/config.hocon b/modules/runtime-common/src/test/resources/config_parser_test/config.hocon
new file mode 100644
index 0000000..89aba02
--- /dev/null
+++ b/modules/runtime-common/src/test/resources/config_parser_test/config.hocon
@@ -0,0 +1,9 @@
+{
+  "field1": "value1",
+  "field2": 10,
+  "field3": true,
+  "field4": {
+    "field41": "value41",
+    "field42": "value42"
+  }
+}
\ No newline at end of file
diff --git a/modules/runtime-common/src/test/resources/config_parser_test/config_correct_namespace.hocon b/modules/runtime-common/src/test/resources/config_parser_test/config_correct_namespace.hocon
new file mode 100644
index 0000000..ed8ec5e
--- /dev/null
+++ b/modules/runtime-common/src/test/resources/config_parser_test/config_correct_namespace.hocon
@@ -0,0 +1,9 @@
+snowplow {
+  "field1": "value1",
+  "field2": 10,
+  "field3": true,
+  "field4": {
+    "field41": "value41",
+    "field42": "value42"
+  }
+}
\ No newline at end of file
diff --git a/modules/runtime-common/src/test/resources/config_parser_test/config_invalid.hocon b/modules/runtime-common/src/test/resources/config_parser_test/config_invalid.hocon
new file mode 100644
index 0000000..adf602a
--- /dev/null
+++ b/modules/runtime-common/src/test/resources/config_parser_test/config_invalid.hocon
@@ -0,0 +1,9 @@
+{
+  "field1": "value1",
+  "field2": 10,
+  "field3": true,
+  "field4":
+    "field41": "value41",
+    "field42": "value42"
+  }
+}
\ No newline at end of file
diff --git a/modules/runtime-common/src/test/resources/config_parser_test/config_missing_field.hocon b/modules/runtime-common/src/test/resources/config_parser_test/config_missing_field.hocon
new file mode 100644
index 0000000..952cea2
--- /dev/null
+++ b/modules/runtime-common/src/test/resources/config_parser_test/config_missing_field.hocon
@@ -0,0 +1,8 @@
+{
+  "field1": "value1",
+  "field2": 10,
+  "field3": true,
+  "field4": {
+    "field42": "value42"
+  }
+}
\ No newline at end of file
diff --git a/modules/runtime-common/src/test/resources/config_parser_test/config_with_set_env.hocon b/modules/runtime-common/src/test/resources/config_parser_test/config_with_set_env.hocon
new file mode 100644
index 0000000..27cd959
--- /dev/null
+++ b/modules/runtime-common/src/test/resources/config_parser_test/config_with_set_env.hocon
@@ -0,0 +1,9 @@
+{
+  "field1": "value1",
+  "field2": 10,
+  "field3": true,
+  "field4": {
+    "field41": ${CONFIG_PARSER_TEST_ENV},
+    "field42": "value42"
+  }
+}
\ No newline at end of file
diff --git a/modules/runtime-common/src/test/resources/config_parser_test/config_with_substitution.hocon b/modules/runtime-common/src/test/resources/config_parser_test/config_with_substitution.hocon
new file mode 100644
index 0000000..d922980
--- /dev/null
+++ b/modules/runtime-common/src/test/resources/config_parser_test/config_with_substitution.hocon
@@ -0,0 +1,13 @@
+{
+  "field1": ${subfield.a},
+  "field2": 10,
+  "field3": true,
+  "field4": {
+    "field41": ${subfield.b},
+    "field42": "value42"
+  }
+  "subfield": {
+    "a": "sub1"
+    "b": "sub2"
+  }
+}
\ No newline at end of file
diff --git a/modules/runtime-common/src/test/resources/config_parser_test/config_with_unset_env.hocon b/modules/runtime-common/src/test/resources/config_parser_test/config_with_unset_env.hocon
new file mode 100644
index 0000000..ddf2fbf
--- /dev/null
+++ b/modules/runtime-common/src/test/resources/config_parser_test/config_with_unset_env.hocon
@@ -0,0 +1,9 @@
+{
+  "field1": "value1",
+  "field2": 10,
+  "field3": true,
+  "field4": {
+    "field41": ${UNSET_ENV_VAR},
+    "field42": "value42"
+  }
+}
\ No newline at end of file
diff --git a/modules/runtime-common/src/test/resources/config_parser_test/config_wrong_namespace.hocon b/modules/runtime-common/src/test/resources/config_parser_test/config_wrong_namespace.hocon
new file mode 100644
index 0000000..1e016b6
--- /dev/null
+++ b/modules/runtime-common/src/test/resources/config_parser_test/config_wrong_namespace.hocon
@@ -0,0 +1,9 @@
+wrongnamespace {
+  "field1": "value1",
+  "field2": 10,
+  "field3": true,
+  "field4": {
+    "field41": "value41",
+    "field42": "value42"
+  }
+}
\ No newline at end of file
diff --git a/modules/runtime-common/src/test/resources/config_parser_test/iglu_resolver.json b/modules/runtime-common/src/test/resources/config_parser_test/iglu_resolver.json
new file mode 100644
index 0000000..9fa1429
--- /dev/null
+++ b/modules/runtime-common/src/test/resources/config_parser_test/iglu_resolver.json
@@ -0,0 +1,28 @@
+{
+  "schema": "iglu:com.snowplowanalytics.iglu/resolver-config/jsonschema/1-0-1",
+  "data": {
+    "cacheSize": 500,
+    "repositories": [
+      {
+        "name": "Iglu Central",
+        "priority": 0,
+        "vendorPrefixes": [ "com.snowplowanalytics" ],
+        "connection": {
+          "http": {
+            "uri": "http://iglucentral.com"
+          }
+        }
+      },
+      {
+        "name": "Iglu Central - GCP Mirror",
+        "priority": 1,
+        "vendorPrefixes": [ "com.snowplowanalytics" ],
+        "connection": {
+          "http": {
+            "uri": "http://mirror01.iglucentral.com"
+          }
+        }
+      }
+    ]
+  }
+}
\ No newline at end of file
diff --git a/modules/runtime-common/src/test/resources/config_parser_test/iglu_resolver_invalid.json b/modules/runtime-common/src/test/resources/config_parser_test/iglu_resolver_invalid.json
new file mode 100644
index 0000000..0ea0bbd
--- /dev/null
+++ b/modules/runtime-common/src/test/resources/config_parser_test/iglu_resolver_invalid.json
@@ -0,0 +1,27 @@
+{
+  "schema": "iglu:com.snowplowanalytics.iglu/resolver-config/jsonschema/1-0-1",
+  "data": {
+    "cacheSize": 500,
+    "repositories": [
+        "name": "Iglu Central",
+        "priority": 0,
+        "vendorPrefixes": [ "com.snowplowanalytics" ],
+        "connection": {
+          "http": {
+            "uri": "http://iglucentral.com"
+          }
+        }
+      },
+      {
+        "name": "Iglu Central - GCP Mirror",
+        "priority": 1,
+        "vendorPrefixes": [ "com.snowplowanalytics" ],
+        "connection": {
+          "http": {
+            "uri": "http://mirror01.iglucentral.com"
+          }
+        }
+      }
+    ]
+  }
+}
\ No newline at end of file
diff --git a/modules/runtime-common/src/test/resources/config_parser_test/iglu_resolver_missing_field.json b/modules/runtime-common/src/test/resources/config_parser_test/iglu_resolver_missing_field.json
new file mode 100644
index 0000000..07e1cbd
--- /dev/null
+++ b/modules/runtime-common/src/test/resources/config_parser_test/iglu_resolver_missing_field.json
@@ -0,0 +1,27 @@
+{
+  "schema": "iglu:com.snowplowanalytics.iglu/resolver-config/jsonschema/1-0-1",
+  "data": {
+    "repositories": [
+      {
+        "name": "Iglu Central",
+        "priority": 0,
+        "vendorPrefixes": [ "com.snowplowanalytics" ],
+        "connection": {
+          "http": {
+            "uri": "http://iglucentral.com"
+          }
+        }
+      },
+      {
+        "name": "Iglu Central - GCP Mirror",
+        "priority": 1,
+        "vendorPrefixes": [ "com.snowplowanalytics" ],
+        "connection": {
+          "http": {
+            "uri": "http://mirror01.iglucentral.com"
+          }
+        }
+      }
+    ]
+  }
+}
\ No newline at end of file
diff --git a/modules/runtime-common/src/test/scala/com/snowplowanalytics/snowplow/runtime/ConfigParserSpec.scala b/modules/runtime-common/src/test/scala/com/snowplowanalytics/snowplow/runtime/ConfigParserSpec.scala
new file mode 100644
index 0000000..3840aad
--- /dev/null
+++ b/modules/runtime-common/src/test/scala/com/snowplowanalytics/snowplow/runtime/ConfigParserSpec.scala
@@ -0,0 +1,222 @@
+/*
+ * Copyright (c) 2023-present Snowplow Analytics Ltd. All rights reserved.
+ *
+ * This program is licensed to you under the Snowplow Community License Version 1.0,
+ * and you may not use this file except in compliance with the Snowplow Community License Version 1.0.
+ * You may obtain a copy of the Snowplow Community License Version 1.0 at https://docs.snowplow.io/community-license-1.0
+ */
+package com.snowplowanalytics.snowplow.runtime
+
+import java.nio.file.Paths
+import io.circe.literal._
+import io.circe.Decoder
+import io.circe.generic.semiauto._
+import cats.effect.IO
+import cats.effect.testing.specs2.CatsEffect
+import org.specs2.Specification
+import com.snowplowanalytics.iglu.client.resolver.Resolver
+
+class ConfigParserSpec extends Specification with CatsEffect {
+  import ConfigParserSpec._
+
+  def is = s2"""
+  ConfigParser should
+    parse iglu resolver json correctly $parseIgluResolverCorrectly
+    fail when iglu resolver json is missing required field $igluResolverMissingField
+    fail when iglu resolver json is invalid $igluResolverInvalid
+    fail when iglu resolver json file doesn't exist $igluResolverDoesNotExist
+    parse config with custom class correctly $parseCustomClassConfig
+    parse config with 'snowplow' namespace correctly $parseConfigWithCorrectNamespace
+    parse config with substitution correctly $parseConfigWithSubstitution
+    fail when wrong namespace is used in the config $configWithWrongNamespace
+    fail when config hocon is missing required field $configMissingField
+    fail when config hocon is invalid $configInvalid
+    fail when config hocon file doesn't exist $configDoesNotExist
+    parse config with env variable correctly $parseConfigWithEnvVariable
+    fail when env variable in the config isn't set $failWhenEnvVariableNotSet
+  """
+
+  def parseIgluResolverCorrectly = {
+    val expected = Resolver.ResolverConfig(
+      cacheSize = 500,
+      cacheTtl  = None,
+      repositoryRefs = List(
+        json"""
+          {
+            "name": "Iglu Central",
+            "priority": 0,
+            "vendorPrefixes": [ "com.snowplowanalytics" ],
+            "connection": {
+              "http": {
+                "uri": "http://iglucentral.com"
+              }
+            }
+          }
+        """,
+        json"""
+          {
+            "name": "Iglu Central - GCP Mirror",
+            "priority": 1,
+            "vendorPrefixes": [ "com.snowplowanalytics" ],
+            "connection": {
+              "http": {
+                "uri": "http://mirror01.iglucentral.com"
+              }
+            }
+          }
+        """
+      )
+    )
+    val path = Paths.get("src/test/resources/config_parser_test/iglu_resolver.json")
+    ConfigParser
+      .igluResolverFromFile[IO](path)
+      .value
+      .map(_ must beRight(expected))
+  }
+
+  def igluResolverMissingField = {
+    val expected = "DecodingFailure at .cacheSize: Missing required field"
+    val path     = Paths.get("src/test/resources/config_parser_test/iglu_resolver_missing_field.json")
+    ConfigParser
+      .igluResolverFromFile[IO](path)
+      .value
+      .map(_ must beLeft(expected))
+  }
+
+  def igluResolverInvalid = {
+    val expected =
+      "String: 6: List should have ended with ] or had a comma, instead had token: ':' (if you want ':' to be part of a string value, then double-quote it)"
+    val path = Paths.get("src/test/resources/config_parser_test/iglu_resolver_invalid.json")
+    ConfigParser
+      .igluResolverFromFile[IO](path)
+      .value
+      .map(_ must beLeft(expected))
+  }
+
+  def igluResolverDoesNotExist = {
+    val expectedPattern = "Error reading .*/iglu_resolver_nonexist.json file from filesystem: .*/iglu_resolver_nonexist.json".r
+    val path            = Paths.get("src/test/resources/config_parser_test/iglu_resolver_nonexist.json")
+    ConfigParser
+      .igluResolverFromFile[IO](path)
+      .value
+      .map(_ must beLike { case Left(expectedPattern(_*)) => ok })
+  }
+
+  def parseCustomClassConfig = {
+    val expected = TestConfig(
+      field1 = "value1",
+      field2 = 10,
+      field3 = true,
+      field4 = TestConfig.Subfield(field41 = "value41", field42 = "value42")
+    )
+    val path = Paths.get("src/test/resources/config_parser_test/config.hocon")
+    ConfigParser
+      .configFromFile[IO, TestConfig](path)
+      .value
+      .map(_ must beRight(expected))
+  }
+
+  def parseConfigWithCorrectNamespace = {
+    val expected = TestConfig(
+      field1 = "value1",
+      field2 = 10,
+      field3 = true,
+      field4 = TestConfig.Subfield(field41 = "value41", field42 = "value42")
+    )
+    val path = Paths.get("src/test/resources/config_parser_test/config_correct_namespace.hocon")
+    ConfigParser
+      .configFromFile[IO, TestConfig](path)
+      .value
+      .map(_ must beRight(expected))
+  }
+
+  def parseConfigWithSubstitution = {
+    val expected = TestConfig(
+      field1 = "sub1",
+      field2 = 10,
+      field3 = true,
+      field4 = TestConfig.Subfield(field41 = "sub2", field42 = "value42")
+    )
+    val path = Paths.get("src/test/resources/config_parser_test/config_with_substitution.hocon")
+    ConfigParser
+      .configFromFile[IO, TestConfig](path)
+      .value
+      .map(_ must beRight(expected))
+  }
+
+  def configWithWrongNamespace = {
+    val expected = "Cannot resolve config: DecodingFailure at .field1: Missing required field"
+    val path     = Paths.get("src/test/resources/config_parser_test/config_wrong_namespace.hocon")
+    ConfigParser
+      .configFromFile[IO, TestConfig](path)
+      .value
+      .map(_ must beLeft(expected))
+  }
+
+  def configMissingField = {
+    val expected = "Cannot resolve config: DecodingFailure at .field41: Missing required field"
+    val path     = Paths.get("src/test/resources/config_parser_test/config_missing_field.hocon")
+    ConfigParser
+      .configFromFile[IO, TestConfig](path)
+      .value
+      .map(_ must beLeft(expected))
+  }
+
+  def configInvalid = {
+    val expected =
+      "String: 6: Expecting close brace } or a comma, got ':' (if you intended ':' to be part of a key or string value, try enclosing the key or value in double quotes)"
+    val path = Paths.get("src/test/resources/config_parser_test/config_invalid.hocon")
+    ConfigParser
+      .configFromFile[IO, TestConfig](path)
+      .value
+      .map(_ must beLeft(expected))
+  }
+
+  def configDoesNotExist = {
+    val expectedPattern = """Error reading .*/config_nonexist.hocon file from filesystem: .*/config_nonexist.hocon""".r
+    val path            = Paths.get("src/test/resources/config_parser_test/config_nonexist.hocon")
+    ConfigParser
+      .configFromFile[IO, TestConfig](path)
+      .value
+      .map(_ must beLike { case Left(expectedPattern(_*)) => ok })
+  }
+
+  def parseConfigWithEnvVariable = {
+    val expected = TestConfig(
+      field1 = "value1",
+      field2 = 10,
+      field3 = true,
+      field4 = TestConfig.Subfield(field41 = "envValue", field42 = "value42")
+    )
+    val path = Paths.get("src/test/resources/config_parser_test/config_with_set_env.hocon")
+    ConfigParser
+      .configFromFile[IO, TestConfig](path)
+      .value
+      .map(_ must beRight(expected))
+  }
+
+  def failWhenEnvVariableNotSet = {
+    val expected = "Cannot resolve config: String: 6: Could not resolve substitution to a value: ${UNSET_ENV_VAR}"
+    val path     = Paths.get("src/test/resources/config_parser_test/config_with_unset_env.hocon")
+    ConfigParser
+      .configFromFile[IO, TestConfig](path)
+      .value
+      .map(_ must beLeft(expected))
+  }
+}
+
+object ConfigParserSpec {
+
+  case class TestConfig(
+    field1: String,
+    field2: Int,
+    field3: Boolean,
+    field4: TestConfig.Subfield
+  )
+  object TestConfig {
+    case class Subfield(field41: String, field42: String)
+
+    implicit val testConfigDecoder: Decoder[TestConfig] = deriveDecoder[TestConfig]
+    implicit val subfieldDecoder: Decoder[Subfield]     = deriveDecoder[Subfield]
+  }
+}
diff --git a/project/BuildSettings.scala b/project/BuildSettings.scala
index 35b1faf..7b88e6c 100644
--- a/project/BuildSettings.scala
+++ b/project/BuildSettings.scala
@@ -42,6 +42,7 @@ object BuildSettings {
     scalacOptions += "-Ywarn-macros:after",
     scalacOptions += "-Wconf:origin=scala.collection.compat.*:s",
     Test / fork := true,
+    Test / envVars := Map("CONFIG_PARSER_TEST_ENV" -> "envValue"),
     addCompilerPlugin(Dependencies.betterMonadicFor),
     addCompilerPlugin(Dependencies.kindProjector),
     ThisBuild / autoAPIMappings := true,