Reworked for simplified flake

modules/bitcoind/default.nix

@@ -0,0 +1,34 @@
+{ config, specialConfig, lib, pkgs, ... }:
+{
+    #################################
+    # Bitcoin Core (bitcoind)
+    #################################
+    services.bitcoind = {
+      enable = true;
+      address = "0.0.0.0";
+      port = 23002;
+      listen = true;
+      listenWhitelisted = true;
+      whitelistedPort = 8335;
+      # dataDir = "/var/lib/bitcoind";
+      rpc = {
+        address = "0.0.0.0";
+        port = 8332;
+        threads = 4;
+        allowip = [
+          "0.0.0.0"
+        ];
+      };
+      regtest = false;
+      # network = "regtest"; # or "mainnet"
+      dataDirReadableByGroup = false;
+      disablewallet = null;
+      dbCache = 4000;
+      prune = 10000;
+      txindex = true;
+      zmqpubrawblock = "tcp://0.0.0.0:28332";
+      zmqpubrawtx = "tcp://0.0.0.0:28333";
+      user = "bitcoind";
+      group = "bitcoind";
+    };
+}

modules/btcpay/default.nix

@@ -0,0 +1,18 @@
+{ config, specialConfig, lib, pkgs, ... }:
+{
+
+    nix-bitcoin.generateSecrets = true;
+    # nix-bitcoin.secretsDir = "/var/lib/secrets";
+    services.btcpayserver = {
+      enable = true;
+      address = "0.0.0.0";
+      port = 23002;
+      # dataDir = "/var/lib/btcpayserver";
+      lbtc = true;
+      user = "btcpayserver";
+      group = "btcpayserver";
+      # If needed, direct BTCPay to same PostgreSQL:
+      # explorerpostgres = "User ID=nbxplorer;Host=localhost;Port=5432;Database=nbxplorermainnet;";
+      # Set environment variables as needed for additional DB, etc.
+    };
+}

modules/nbxplorer/default.nix

@@ -0,0 +1,15 @@
+{ config, specialConfig, lib, pkgs, ... }:
+{
+    services.nbxplorer = {
+      enable = true;
+      address = "0.0.0.0";
+      port = 24444;
+      # dataDir = "/var/lib/nbxplorer";
+      user = "nbxplorer";
+      group = "nbxplorer";
+      # Database connection string to external/local PostgreSQL:
+      # postgres = "User ID=nbxplorer;Host=0.0.0.0;Port=5432;Database=nbxplorermainnet;";
+      # chains = [ "btc" "ltc" "lbtc" ];
+      # Additional NBXplorer server args/overrides can go here.
+    };
+}

modules/postgresql/default.nix

@@ -0,0 +1,19 @@
+{ config, lib, pkgs, specialConfig, ... }:
+{
+  # Disable local postgres (so NixOS won't start or manage it)
+  services = {
+      postgresql = {
+      enable = true;
+      ensureDatabases = [ "nbxplorermainnet" "btcpaydb" ];
+      ensureUsers = [
+        { name = "nbxplorer"; ensureDBOwnership = true; }
+        { name = "btcpay"; ensureDBOwnership = true; }
+      ];
+      authentication = ''
+        local all        all                      trust
+        host  all        all     0.0.0.1/32     trust
+        host  all        all     ::1/128          trust
+      '';
+    };
+  };
+}