diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3a66e51a3d..6b087d63d9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 - [#2834](https://github.com/poanetwork/blockscout/pull/2834) - always redirect to checksummed hash
 
 ### Fixes
+- [#3021](https://github.com/poanetwork/blockscout/pull/3021) - Refine dev config
 - [#3016](https://github.com/poanetwork/blockscout/pull/3016), [#3017](https://github.com/poanetwork/blockscout/pull/3017) - Fix token instance QR code data
 - [#3014](https://github.com/poanetwork/blockscout/pull/3014) - Fix checksum address feature for tokens pages
 - [#3012](https://github.com/poanetwork/blockscout/pull/3012) - Speedup token transfers list query
diff --git a/apps/block_scout_web/README.md b/apps/block_scout_web/README.md
index e24cbc6487..6d0ae03073 100644
--- a/apps/block_scout_web/README.md
+++ b/apps/block_scout_web/README.md
@@ -4,9 +4,9 @@ This is a tool for inspecting and analyzing the POA Network blockchain from a we
 
 ## Machine Requirements
 
-* Erlang/OTP 20.2+
-* Elixir 1.5+
-* Postgres 10.0
+* Erlang/OTP 21+
+* Elixir 1.9+
+* Postgres 10.3
 
 
 ## Required Accounts
@@ -21,7 +21,6 @@ This is a tool for inspecting and analyzing the POA Network blockchain from a we
 To get BlockScout Web interface up and running locally:
 
   * Setup `../explorer`
-  * Set up some default configuration with: `$ cp config/dev.secret.exs.example config/dev.secret.exs`
   * Install Node.js dependencies with `$ cd assets && npm install && cd ..`
   * Start Phoenix with `$ mix phx.server` (This can be run from this directory or the project root: the project root is recommended.)
 
diff --git a/apps/block_scout_web/config/dev.exs b/apps/block_scout_web/config/dev.exs
index fa1e25341d..b841d8efe1 100644
--- a/apps/block_scout_web/config/dev.exs
+++ b/apps/block_scout_web/config/dev.exs
@@ -15,6 +15,8 @@ port =
   end
 
 config :block_scout_web, BlockScoutWeb.Endpoint,
+  secret_key_base:
+    System.get_env("SECRET_KEY_BASE") || "RMgI4C1HSkxsEjdhtGMfwAHfyT6CKWXOgzCboJflfSm4jeAlic52io05KB6mqzc5",
   http: [
     port: port || 4000
   ],
@@ -79,5 +81,3 @@ config :logger, :block_scout_web,
 # Set a higher stacktrace during development. Avoid configuring such
 # in production as building large stacktraces may be expensive.
 config :phoenix, :stacktrace_depth, 20
-
-import_config "dev.secret.exs"
diff --git a/apps/block_scout_web/config/dev.secret.exs.example b/apps/block_scout_web/config/dev.secret.exs.example
deleted file mode 100644
index 3c358188f2..0000000000
--- a/apps/block_scout_web/config/dev.secret.exs.example
+++ /dev/null
@@ -1,5 +0,0 @@
-use Mix.Config
-
-# Configures the endpoint
-config :block_scout_web, BlockScoutWeb.Endpoint,
-  secret_key_base: "RMgI4C1HSkxsEjdhtGMfwAHfyT6CKWXOgzCboJflfSm4jeAlic52io05KB6mqzc5"
diff --git a/apps/explorer/README.md b/apps/explorer/README.md
index 22b0dc96b6..2ad45d37a6 100644
--- a/apps/explorer/README.md
+++ b/apps/explorer/README.md
@@ -5,9 +5,9 @@ This is a tool for inspecting and analyzing the POA Network blockchain.
 
 ## Machine Requirements
 
-* Erlang/OTP 20.2+
-* Elixir 1.5+
-* Postgres 10.0
+* Erlang/OTP 21+
+* Elixir 1.9+
+* Postgres 10.3
 
 
 ## Required Accounts
@@ -21,7 +21,6 @@ This is a tool for inspecting and analyzing the POA Network blockchain.
 
 To get BlockScout up and running locally:
 
-  * Set up some default configuration with: `$ cp config/dev.secret.exs.example config/dev.secret.exs`
   * Install dependencies with `$ mix do deps.get, local.rebar, deps.compile, compile`
   * Create and migrate your database with `$ mix ecto.create && mix ecto.migrate`
   * Run IEx (Interactive Elixir) to access the index and explore: `$ iex -S mix`
diff --git a/apps/explorer/config/dev.exs b/apps/explorer/config/dev.exs
index a9d0f53b15..cbed0f47d7 100644
--- a/apps/explorer/config/dev.exs
+++ b/apps/explorer/config/dev.exs
@@ -2,9 +2,8 @@ use Mix.Config
 
 # Configure your database
 config :explorer, Explorer.Repo,
-  database: "explorer_dev",
-  hostname: "localhost",
-  pool_size: 20,
+  url: System.get_env("DATABASE_URL"),
+  pool_size: String.to_integer(System.get_env("POOL_SIZE") || "50"),
   timeout: :timer.seconds(80)
 
 config :explorer, Explorer.Tracer, env: "dev", disabled?: true
@@ -23,8 +22,6 @@ config :logger, :token_instances,
   path: Path.absname("logs/dev/explorer/tokens/token_instances.log"),
   metadata_filter: [fetcher: :token_instances]
 
-import_config "dev.secret.exs"
-
 variant =
   if is_nil(System.get_env("ETHEREUM_JSONRPC_VARIANT")) do
     "ganache"
diff --git a/apps/explorer/config/dev.secret.exs.example b/apps/explorer/config/dev.secret.exs.example
deleted file mode 100644
index bde88d33f1..0000000000
--- a/apps/explorer/config/dev.secret.exs.example
+++ /dev/null
@@ -1,10 +0,0 @@
-use Mix.Config
-
-# Configure your database
-config :explorer, Explorer.Repo,
-  database: "explorer_dev",
-  hostname: "localhost",
-  username: "postgres",
-  password: "<REPLACE WITH THE PASSWORD YOU CHOSE>",
-  pool_size: 20,
-  timeout: 80_000