diff --git a/app/src/confgen/core.py b/app/src/confgen/core.py
new file mode 100644
index 0000000..9e0c4d1
--- /dev/null
+++ b/app/src/confgen/core.py
@@ -0,0 +1,174 @@
+"""Core logic for confgen configuration generation."""
+
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Optional
+
+import yaml
+
+
+@dataclass
+class TemplateConfig:
+    """Configuration for a template."""
+
+    name: str
+    path: Path
+    format: Optional[str] = None
+    schema: Optional[str] = None
+
+
+@dataclass
+class EnvironmentConfig:
+    """Configuration for an environment."""
+
+    name: str
+    variables: dict
+
+
+@dataclass
+class ConfgenConfig:
+    """Main configuration for confgen."""
+
+    templates: dict[str, TemplateConfig]
+    environments: dict[str, EnvironmentConfig]
+
+
+@dataclass
+class GeneratedConfig:
+    """Result of generating a configuration."""
+
+    content: str
+    format: str
+    schema_validated: bool = False
+
+
+class ConfgenCore:
+    """Core class for configuration generation."""
+
+    def __init__(
+        self,
+        config_dir: Path,
+        templates_dir: Path,
+        output_dir: Path,
+        environment: str = "dev",
+    ):
+        self.config_dir = Path(config_dir)
+        self.templates_dir = Path(templates_dir)
+        self.output_dir = Path(output_dir)
+        self.default_environment = environment
+        self.config = self._load_config()
+
+    def _load_config(self) -> ConfgenConfig:
+        """Load configuration from confgen.yaml."""
+        config_file = self.config_dir / "confgen.yaml"
+
+        if not config_file.exists():
+            return ConfgenConfig(templates={}, environments={})
+
+        with open(config_file) as f:
+            data = yaml.safe_load(f) or {}
+
+        templates = {}
+        for name, tmpl_data in data.get("templates", {}).items():
+            path = Path(tmpl_data.get("path", f"templates/{name}.j2"))
+            if not path.is_absolute():
+                path = self.config_dir / path
+            templates[name] = TemplateConfig(
+                name=name,
+                path=path,
+                format=tmpl_data.get("format"),
+                schema=tmpl_data.get("schema"),
+            )
+
+        environments = {}
+        for name, env_data in data.get("environments", {}).items():
+            environments[name] = EnvironmentConfig(
+                name=name,
+                variables=env_data.get("variables", {}),
+            )
+
+        return ConfgenConfig(templates=templates, environments=environments)
+
+    def get_template(self, name: str) -> Optional[TemplateConfig]:
+        """Get a template by name."""
+        return self.config.templates.get(name)
+
+    def get_environment(self, name: str) -> Optional[EnvironmentConfig]:
+        """Get an environment by name."""
+        return self.config.environments.get(name)
+
+    def generate_config(
+        self,
+        template_name: str,
+        environment: str,
+        format: Optional[str] = None,
+    ) -> GeneratedConfig:
+        """Generate a configuration from a template."""
+        from .template import TemplateEngine
+        from .parsers import ConfigParser
+        from .secrets import SecretsResolver
+        from .validator import SchemaValidator
+
+        tmpl = self.get_template(template_name)
+        if not tmpl:
+            raise ValueError(f"Template '{template_name}' not found")
+
+        env_config = self.get_environment(environment)
+        variables = env_config.variables if env_config else {}
+
+        template_path = tmpl.path
+        if not template_path.exists():
+            template_path = self.templates_dir / f"{template_name}.j2"
+            if not template_path.exists():
+                raise ValueError(f"Template file not found: {template_path}")
+
+        template_engine = TemplateEngine()
+        secrets_resolver = SecretsResolver()
+
+        variables["environment"] = environment
+
+        with open(template_path) as f:
+            template_content = f.read()
+
+        content = secrets_resolver.resolve(template_content)
+        rendered_content = template_engine.render(content, variables)
+
+        output_format = format or tmpl.format or "yaml"
+        parser = ConfigParser()
+
+        if output_format == "json":
+            parsed_data = parser.parse_json(rendered_content)
+            output_content = parser.to_json(parsed_data)
+        elif output_format == "toml":
+            parsed_data = parser.parse_toml(rendered_content)
+            output_content = parser.to_toml(parsed_data)
+        else:
+            parsed_data = parser.parse_yaml(rendered_content)
+            output_content = parser.to_yaml(parsed_data)
+
+        schema_validated = False
+        if tmpl.schema:
+            schema_path = tmpl.schema
+            if not Path(schema_path).is_absolute():
+                schema_path = self.config_dir / schema_path
+
+            if schema_path.exists():
+                validator = SchemaValidator(schema_path)
+                is_valid, _ = validator.validate(parsed_data)
+                if not is_valid:
+                    raise ValueError("Schema validation failed")
+                schema_validated = True
+
+        return GeneratedConfig(
+            content=output_content,
+            format=output_format,
+            schema_validated=schema_validated,
+        )
+
+    def list_templates(self) -> list[str]:
+        """List available template names."""
+        return list(self.config.templates.keys())
+
+    def list_environments(self) -> list[str]:
+        """List available environment names."""
+        return list(self.config.environments.keys())