diff --git a/openrag/core/chunking/__init__.py b/openrag/core/chunking/__init__.py
index e69de29bb..f2caca418 100644
--- a/openrag/core/chunking/__init__.py
+++ b/openrag/core/chunking/__init__.py
@@ -0,0 +1,6 @@
+"""ChunkingStrategy ABC + registry."""
+
+from openrag.core.chunking.chunking_strategy import ChunkingStrategy
+from openrag.core.chunking.registry import chunking_registry
+
+__all__ = ["ChunkingStrategy", "chunking_registry"]
diff --git a/openrag/core/chunking/chunking_strategy.py b/openrag/core/chunking/chunking_strategy.py
new file mode 100644
index 000000000..2f2dbf93d
--- /dev/null
+++ b/openrag/core/chunking/chunking_strategy.py
@@ -0,0 +1,17 @@
+"""Abstract chunking strategy interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+from openrag.core.models.chunk import Chunk
+from openrag.core.models.document import ProcessedDocument
+
+
+class ChunkingStrategy(ABC):
+    """Base class for all chunking strategies."""
+
+    @abstractmethod
+    def chunk(self, document: ProcessedDocument, partition: str = "default") -> list[Chunk]:
+        """Split a processed document into chunks."""
+        ...
diff --git a/openrag/core/chunking/registry.py b/openrag/core/chunking/registry.py
new file mode 100644
index 000000000..80ca0986c
--- /dev/null
+++ b/openrag/core/chunking/registry.py
@@ -0,0 +1,6 @@
+"""Chunking strategy registry."""
+
+from openrag.core.chunking.chunking_strategy import ChunkingStrategy
+from openrag.core.utils.registry import Registry
+
+chunking_registry: Registry[ChunkingStrategy] = Registry("chunking")
diff --git a/openrag/core/embeddings/__init__.py b/openrag/core/embeddings/__init__.py
index e69de29bb..bb83819db 100644
--- a/openrag/core/embeddings/__init__.py
+++ b/openrag/core/embeddings/__init__.py
@@ -0,0 +1,6 @@
+"""Embedder ABC + registry."""
+
+from openrag.core.embeddings.embedder import Embedder
+from openrag.core.embeddings.registry import embedder_registry
+
+__all__ = ["Embedder", "embedder_registry"]
diff --git a/openrag/core/embeddings/embedder.py b/openrag/core/embeddings/embedder.py
new file mode 100644
index 000000000..1ac34aa05
--- /dev/null
+++ b/openrag/core/embeddings/embedder.py
@@ -0,0 +1,25 @@
+"""Abstract embedder interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+
+class Embedder(ABC):
+    """Base class for all embedding providers."""
+
+    @abstractmethod
+    async def embed(self, texts: list[str]) -> list[list[float]]:
+        """Embed a batch of texts, returning vectors."""
+        ...
+
+    @abstractmethod
+    async def embed_single(self, text: str) -> list[float]:
+        """Embed a single text."""
+        ...
+
+    @property
+    @abstractmethod
+    def dimension(self) -> int:
+        """Return the embedding dimension."""
+        ...
diff --git a/openrag/core/embeddings/registry.py b/openrag/core/embeddings/registry.py
new file mode 100644
index 000000000..a79e08d7c
--- /dev/null
+++ b/openrag/core/embeddings/registry.py
@@ -0,0 +1,6 @@
+"""Embedder registry."""
+
+from openrag.core.embeddings.embedder import Embedder
+from openrag.core.utils.registry import Registry
+
+embedder_registry: Registry[Embedder] = Registry("embedder")
diff --git a/openrag/core/indexing/parsers/__init__.py b/openrag/core/indexing/parsers/__init__.py
index e69de29bb..16e23bfb4 100644
--- a/openrag/core/indexing/parsers/__init__.py
+++ b/openrag/core/indexing/parsers/__init__.py
@@ -0,0 +1,6 @@
+"""DocumentParser ABC + registry."""
+
+from openrag.core.indexing.parsers.document_parser import DocumentParser
+from openrag.core.indexing.parsers.registry import parser_registry
+
+__all__ = ["DocumentParser", "parser_registry"]
diff --git a/openrag/core/indexing/parsers/document_parser.py b/openrag/core/indexing/parsers/document_parser.py
new file mode 100644
index 000000000..aedd0b383
--- /dev/null
+++ b/openrag/core/indexing/parsers/document_parser.py
@@ -0,0 +1,21 @@
+"""Abstract document parser interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+from openrag.core.models.document import Document, ProcessedDocument
+
+
+class DocumentParser(ABC):
+    """Base class for all document parsers (PDF, text, HTML, image, audio, etc.)."""
+
+    @abstractmethod
+    async def parse(self, document: Document) -> ProcessedDocument:
+        """Parse a document into text blocks and images."""
+        ...
+
+    @abstractmethod
+    def supported_types(self) -> list[str]:
+        """Return list of DocumentType values this parser handles."""
+        ...
diff --git a/openrag/core/indexing/parsers/registry.py b/openrag/core/indexing/parsers/registry.py
new file mode 100644
index 000000000..2975143b5
--- /dev/null
+++ b/openrag/core/indexing/parsers/registry.py
@@ -0,0 +1,6 @@
+"""Document parser registry."""
+
+from openrag.core.indexing.parsers.document_parser import DocumentParser
+from openrag.core.utils.registry import Registry
+
+parser_registry: Registry[DocumentParser] = Registry("parser")
diff --git a/openrag/core/llm/__init__.py b/openrag/core/llm/__init__.py
index e69de29bb..0a37f2307 100644
--- a/openrag/core/llm/__init__.py
+++ b/openrag/core/llm/__init__.py
@@ -0,0 +1,6 @@
+"""LLM ABC + registry."""
+
+from openrag.core.llm.llm import LLM
+from openrag.core.llm.registry import llm_registry
+
+__all__ = ["LLM", "llm_registry"]
diff --git a/openrag/core/llm/llm.py b/openrag/core/llm/llm.py
new file mode 100644
index 000000000..7e24d85b2
--- /dev/null
+++ b/openrag/core/llm/llm.py
@@ -0,0 +1,57 @@
+"""Abstract LLM interface."""
+
+from __future__ import annotations
+
+import json
+from abc import ABC, abstractmethod
+from collections.abc import AsyncIterator
+
+from openrag.core.utils.exceptions import LLMParsingError
+
+
+class LLM(ABC):
+    """Base class for all LLM providers."""
+
+    @abstractmethod
+    async def generate(self, prompt: str, **kwargs) -> str:
+        """Generate a completion for a prompt."""
+        ...
+
+    @abstractmethod
+    async def chat(self, messages: list[dict[str, str]], **kwargs) -> str:
+        """Chat completion with message list."""
+        ...
+
+    async def generate_json(self, prompt: str, **kwargs) -> dict:
+        """Generate a JSON response. Default: parse generate() output.
+
+        Raises LLMParsingError if the LLM output is not valid JSON.
+        """
+        response = await self.generate(prompt, **kwargs)
+        text = response.strip()
+        try:
+            return json.loads(text)
+        except json.JSONDecodeError as exc:
+            raise LLMParsingError(
+                raw_response=text,
+                parse_error=str(exc),
+            ) from exc
+
+    async def chat_with_tools(
+        self,
+        messages: list[dict[str, str]],
+        tools: list[dict],
+        tool_choice: str | dict = "required",
+        **kwargs,
+    ) -> dict:
+        """Chat completion with function calling.
+
+        Only supported by backends with function calling (e.g., vLLM).
+        Default raises NotImplementedError.
+        """
+        raise NotImplementedError(f"{type(self).__name__} does not support tool calling")
+
+    async def stream_chat(self, messages: list[dict[str, str]], **kwargs) -> AsyncIterator[str]:
+        """Stream chat completion. Default falls back to non-streaming."""
+        result = await self.chat(messages, **kwargs)
+        yield result
diff --git a/openrag/core/llm/registry.py b/openrag/core/llm/registry.py
new file mode 100644
index 000000000..537faac4c
--- /dev/null
+++ b/openrag/core/llm/registry.py
@@ -0,0 +1,6 @@
+"""LLM registry."""
+
+from openrag.core.llm.llm import LLM
+from openrag.core.utils.registry import Registry
+
+llm_registry: Registry[LLM] = Registry("llm")
diff --git a/openrag/core/ports/__init__.py b/openrag/core/ports/__init__.py
index e69de29bb..76344fc8b 100644
--- a/openrag/core/ports/__init__.py
+++ b/openrag/core/ports/__init__.py
@@ -0,0 +1,33 @@
+"""Port interfaces — repository ABCs + CatalogStore aggregate root."""
+
+from openrag.core.ports.audit_log_repo import AuditLogRepository
+from openrag.core.ports.catalog_store import CatalogStore
+from openrag.core.ports.chunk_repo import ChunkRepository
+from openrag.core.ports.conversation_repo import ConversationRepository
+from openrag.core.ports.document_repo import DocumentRepository
+from openrag.core.ports.entity_repo import EntityRepository
+from openrag.core.ports.idempotency_repo import IdempotencyRepository
+from openrag.core.ports.job_repo import JobRepository
+from openrag.core.ports.model_endpoint_repo import ModelEndpointRepository
+from openrag.core.ports.partition_repo import PartitionRepository
+from openrag.core.ports.preset_repo import PresetRepository
+from openrag.core.ports.prompt_repo import PromptRepository
+from openrag.core.ports.topic_tag_repo import TopicTagRepository
+from openrag.core.ports.user_repo import UserRepository
+
+__all__ = [
+    "AuditLogRepository",
+    "CatalogStore",
+    "ChunkRepository",
+    "ConversationRepository",
+    "DocumentRepository",
+    "EntityRepository",
+    "IdempotencyRepository",
+    "JobRepository",
+    "ModelEndpointRepository",
+    "PartitionRepository",
+    "PresetRepository",
+    "PromptRepository",
+    "TopicTagRepository",
+    "UserRepository",
+]
diff --git a/openrag/core/ports/audit_log_repo.py b/openrag/core/ports/audit_log_repo.py
new file mode 100644
index 000000000..2318bc4d1
--- /dev/null
+++ b/openrag/core/ports/audit_log_repo.py
@@ -0,0 +1,24 @@
+"""Audit log repository interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from typing import Any
+
+
+class AuditLogRepository(ABC):
+    """Append-only audit trail."""
+
+    @abstractmethod
+    async def insert(
+        self,
+        user_id: int | None,
+        action: str,
+        resource_type: str,
+        resource_id: str | None = None,
+        details_json: dict | None = None,
+        request_id: str | None = None,
+    ) -> None: ...
+
+    @abstractmethod
+    async def query(self, filters: dict[str, Any], offset: int = 0, limit: int = 50) -> list[dict]: ...
diff --git a/openrag/core/ports/catalog_store.py b/openrag/core/ports/catalog_store.py
new file mode 100644
index 000000000..5f275f6ae
--- /dev/null
+++ b/openrag/core/ports/catalog_store.py
@@ -0,0 +1,88 @@
+"""CatalogStore — aggregate root composing all repository ports.
+
+Concrete implementations (e.g. PostgresStore) own the connection pool
+and compose per-entity repository instances.
+"""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+from openrag.core.ports.audit_log_repo import AuditLogRepository
+from openrag.core.ports.chunk_repo import ChunkRepository
+from openrag.core.ports.conversation_repo import ConversationRepository
+from openrag.core.ports.document_repo import DocumentRepository
+from openrag.core.ports.entity_repo import EntityRepository
+from openrag.core.ports.idempotency_repo import IdempotencyRepository
+from openrag.core.ports.job_repo import JobRepository
+from openrag.core.ports.model_endpoint_repo import ModelEndpointRepository
+from openrag.core.ports.partition_repo import PartitionRepository
+from openrag.core.ports.preset_repo import PresetRepository
+from openrag.core.ports.prompt_repo import PromptRepository
+from openrag.core.ports.topic_tag_repo import TopicTagRepository
+from openrag.core.ports.user_repo import UserRepository
+
+
+class CatalogStore(ABC):
+    """Abstract interface for the relational catalog backing store.
+
+    Concrete implementations (e.g. PostgresStore) live in the services layer.
+    """
+
+    @abstractmethod
+    async def initialize(self) -> None: ...
+
+    @abstractmethod
+    async def shutdown(self) -> None: ...
+
+    @property
+    @abstractmethod
+    def document_repo(self) -> DocumentRepository: ...
+
+    @property
+    @abstractmethod
+    def job_repo(self) -> JobRepository: ...
+
+    @property
+    @abstractmethod
+    def user_repo(self) -> UserRepository: ...
+
+    @property
+    @abstractmethod
+    def prompt_repo(self) -> PromptRepository: ...
+
+    @property
+    @abstractmethod
+    def partition_repo(self) -> PartitionRepository: ...
+
+    @property
+    @abstractmethod
+    def model_endpoint_repo(self) -> ModelEndpointRepository: ...
+
+    @property
+    @abstractmethod
+    def preset_repo(self) -> PresetRepository: ...
+
+    @property
+    @abstractmethod
+    def chunk_repo(self) -> ChunkRepository: ...
+
+    @property
+    @abstractmethod
+    def entity_repo(self) -> EntityRepository: ...
+
+    @property
+    @abstractmethod
+    def topic_tag_repo(self) -> TopicTagRepository: ...
+
+    @property
+    @abstractmethod
+    def conversation_repo(self) -> ConversationRepository: ...
+
+    @property
+    @abstractmethod
+    def audit_log_repo(self) -> AuditLogRepository: ...
+
+    @property
+    @abstractmethod
+    def idempotency_repo(self) -> IdempotencyRepository: ...
diff --git a/openrag/core/ports/chunk_repo.py b/openrag/core/ports/chunk_repo.py
new file mode 100644
index 000000000..e4b986d8e
--- /dev/null
+++ b/openrag/core/ports/chunk_repo.py
@@ -0,0 +1,39 @@
+"""Chunk repository interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+
+class ChunkRepository(ABC):
+    """Bulk CRUD operations for text chunks."""
+
+    @abstractmethod
+    async def bulk_insert(self, chunks: list[dict]) -> int:
+        """Insert multiple chunks. Returns count of inserted rows."""
+        ...
+
+    @abstractmethod
+    async def get_by_ids(self, chunk_ids: list[str]) -> list[dict]:
+        """Batch fetch chunks by IDs."""
+        ...
+
+    @abstractmethod
+    async def get_by_document_id(self, document_id: str) -> list[dict]:
+        """Fetch all chunks for a document, ordered by chunk_index."""
+        ...
+
+    @abstractmethod
+    async def delete_by_document_id(self, document_id: str) -> int:
+        """Delete all chunks belonging to a document. Returns count."""
+        ...
+
+    @abstractmethod
+    async def delete_by_partition(self, partition: str) -> int:
+        """Delete all chunks in a partition. Returns count."""
+        ...
+
+    @abstractmethod
+    async def bm25_search(self, query_text: str, partition: str, top_k: int = 20) -> list[dict]:
+        """Full-text search using tsvector column with ts_rank scoring."""
+        ...
diff --git a/openrag/core/ports/conversation_repo.py b/openrag/core/ports/conversation_repo.py
new file mode 100644
index 000000000..6b1938f11
--- /dev/null
+++ b/openrag/core/ports/conversation_repo.py
@@ -0,0 +1,29 @@
+"""Conversation repository interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+from openrag.core.models.conversation import Conversation, Message
+
+
+class ConversationRepository(ABC):
+    """CRUD operations for conversations and messages."""
+
+    @abstractmethod
+    async def create_conversation(self, conversation: Conversation) -> Conversation: ...
+
+    @abstractmethod
+    async def get_conversation(self, conversation_id: str) -> Conversation | None: ...
+
+    @abstractmethod
+    async def list_conversations(self, user_id: int, partition: str | None = None) -> list[Conversation]: ...
+
+    @abstractmethod
+    async def delete_conversation(self, conversation_id: str) -> bool: ...
+
+    @abstractmethod
+    async def add_message(self, message: Message) -> Message: ...
+
+    @abstractmethod
+    async def list_messages(self, conversation_id: str) -> list[Message]: ...
diff --git a/openrag/core/ports/document_repo.py b/openrag/core/ports/document_repo.py
new file mode 100644
index 000000000..289feed6f
--- /dev/null
+++ b/openrag/core/ports/document_repo.py
@@ -0,0 +1,42 @@
+"""Document repository interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from typing import Any
+
+from openrag.core.models.catalog import DocumentRecord
+
+
+class DocumentRepository(ABC):
+    """CRUD operations for documents."""
+
+    @abstractmethod
+    async def create_document(self, doc: DocumentRecord) -> DocumentRecord: ...
+
+    @abstractmethod
+    async def get_document(self, document_id: str) -> DocumentRecord | None: ...
+
+    @abstractmethod
+    async def list_documents(
+        self,
+        partition: str | list[str] | None = None,
+        status: str | None = None,
+        offset: int = 0,
+        limit: int = 50,
+    ) -> list[DocumentRecord]: ...
+
+    @abstractmethod
+    async def update_document(self, document_id: str, **fields: Any) -> DocumentRecord | None: ...
+
+    @abstractmethod
+    async def delete_document(self, document_id: str) -> bool: ...
+
+    @abstractmethod
+    async def delete_documents_by_partition(self, partition: str) -> int: ...
+
+    @abstractmethod
+    async def count_documents(self, partition: str | list[str] | None = None, status: str | None = None) -> int: ...
+
+    @abstractmethod
+    async def file_exists_in_partition(self, file_id: str, partition: str) -> bool: ...
diff --git a/openrag/core/ports/entity_repo.py b/openrag/core/ports/entity_repo.py
new file mode 100644
index 000000000..a8520484f
--- /dev/null
+++ b/openrag/core/ports/entity_repo.py
@@ -0,0 +1,21 @@
+"""Entity repository interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+
+class EntityRepository(ABC):
+    """CRUD operations for extracted entities."""
+
+    @abstractmethod
+    async def upsert(self, partition: str, entity_type: str, canonical_name: str, aliases: list[str]) -> str: ...
+
+    @abstractmethod
+    async def search(self, partition: str, query: str, top_k: int = 10) -> list[dict]: ...
+
+    @abstractmethod
+    async def get_by_document(self, document_id: str) -> list[dict]: ...
+
+    @abstractmethod
+    async def delete_by_document(self, document_id: str) -> int: ...
diff --git a/openrag/core/ports/idempotency_repo.py b/openrag/core/ports/idempotency_repo.py
new file mode 100644
index 000000000..8a5f65dcd
--- /dev/null
+++ b/openrag/core/ports/idempotency_repo.py
@@ -0,0 +1,15 @@
+"""Idempotency key repository interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+
+class IdempotencyRepository(ABC):
+    """Cache for request idempotency keys."""
+
+    @abstractmethod
+    async def get_by_hash(self, key_hash: str) -> dict | None: ...
+
+    @abstractmethod
+    async def store(self, key_hash: str, http_method: str, status_code: int, response_body: bytes) -> None: ...
diff --git a/openrag/core/ports/job_repo.py b/openrag/core/ports/job_repo.py
new file mode 100644
index 000000000..5e20b6830
--- /dev/null
+++ b/openrag/core/ports/job_repo.py
@@ -0,0 +1,24 @@
+"""Job repository interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from typing import Any
+
+from openrag.core.models.catalog import IndexationJob
+
+
+class JobRepository(ABC):
+    """CRUD operations for indexation jobs."""
+
+    @abstractmethod
+    async def create_job(self, job: IndexationJob) -> IndexationJob: ...
+
+    @abstractmethod
+    async def get_job(self, job_id: str) -> IndexationJob | None: ...
+
+    @abstractmethod
+    async def list_jobs(self, status: str | None = None, offset: int = 0, limit: int = 50) -> list[IndexationJob]: ...
+
+    @abstractmethod
+    async def update_job(self, job_id: str, **fields: Any) -> IndexationJob | None: ...
diff --git a/openrag/core/ports/model_endpoint_repo.py b/openrag/core/ports/model_endpoint_repo.py
new file mode 100644
index 000000000..e907a0ce0
--- /dev/null
+++ b/openrag/core/ports/model_endpoint_repo.py
@@ -0,0 +1,21 @@
+"""Model endpoint repository interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+
+class ModelEndpointRepository(ABC):
+    """CRUD operations for model endpoint configurations."""
+
+    @abstractmethod
+    async def get(self, name: str, model_type: str) -> dict | None: ...
+
+    @abstractmethod
+    async def list_all(self, model_type: str | None = None) -> list[dict]: ...
+
+    @abstractmethod
+    async def upsert(self, name: str, model_type: str, config: dict) -> dict: ...
+
+    @abstractmethod
+    async def delete(self, name: str, model_type: str) -> bool: ...
diff --git a/openrag/core/ports/partition_repo.py b/openrag/core/ports/partition_repo.py
new file mode 100644
index 000000000..00898ce76
--- /dev/null
+++ b/openrag/core/ports/partition_repo.py
@@ -0,0 +1,24 @@
+"""Partition repository interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+
+class PartitionRepository(ABC):
+    """CRUD operations for partitions."""
+
+    @abstractmethod
+    async def create_partition(self, name: str, user_id: int | None = None) -> dict: ...
+
+    @abstractmethod
+    async def get_partition(self, name: str) -> dict | None: ...
+
+    @abstractmethod
+    async def list_partitions(self) -> list[dict]: ...
+
+    @abstractmethod
+    async def delete_partition(self, name: str) -> bool: ...
+
+    @abstractmethod
+    async def partition_exists(self, name: str) -> bool: ...
diff --git a/openrag/core/ports/preset_repo.py b/openrag/core/ports/preset_repo.py
new file mode 100644
index 000000000..363b654fc
--- /dev/null
+++ b/openrag/core/ports/preset_repo.py
@@ -0,0 +1,21 @@
+"""Preset repository interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+
+class PresetRepository(ABC):
+    """CRUD operations for pipeline presets."""
+
+    @abstractmethod
+    async def get(self, name: str, preset_type: str) -> dict | None: ...
+
+    @abstractmethod
+    async def list_all(self, preset_type: str | None = None) -> list[dict]: ...
+
+    @abstractmethod
+    async def upsert(self, name: str, preset_type: str, config: dict) -> dict: ...
+
+    @abstractmethod
+    async def delete(self, name: str, preset_type: str) -> bool: ...
diff --git a/openrag/core/ports/prompt_repo.py b/openrag/core/ports/prompt_repo.py
new file mode 100644
index 000000000..43336f2f5
--- /dev/null
+++ b/openrag/core/ports/prompt_repo.py
@@ -0,0 +1,32 @@
+"""Prompt repository interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+from openrag.core.models.prompt import Prompt
+
+
+class PromptRepository(ABC):
+    """CRUD operations for prompt templates."""
+
+    @abstractmethod
+    async def create_prompt(self, prompt: Prompt) -> Prompt: ...
+
+    @abstractmethod
+    async def get_prompt(self, prompt_id: str) -> Prompt | None: ...
+
+    @abstractmethod
+    async def get_by_type(self, prompt_type: str) -> list[Prompt]: ...
+
+    @abstractmethod
+    async def get_active(self, prompt_type: str) -> Prompt | None: ...
+
+    @abstractmethod
+    async def list_prompts(self) -> list[Prompt]: ...
+
+    @abstractmethod
+    async def update_prompt(self, prompt_id: str, content: str) -> Prompt | None: ...
+
+    @abstractmethod
+    async def delete_prompt(self, prompt_id: str) -> bool: ...
diff --git a/openrag/core/ports/topic_tag_repo.py b/openrag/core/ports/topic_tag_repo.py
new file mode 100644
index 000000000..99287f46c
--- /dev/null
+++ b/openrag/core/ports/topic_tag_repo.py
@@ -0,0 +1,21 @@
+"""Topic tag repository interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+
+class TopicTagRepository(ABC):
+    """CRUD operations for document topic tags."""
+
+    @abstractmethod
+    async def bulk_insert(self, tags: list[dict]) -> int: ...
+
+    @abstractmethod
+    async def get_by_document(self, document_id: str) -> list[dict]: ...
+
+    @abstractmethod
+    async def delete_by_document(self, document_id: str) -> int: ...
+
+    @abstractmethod
+    async def search(self, partition: str, tag: str, top_k: int = 10) -> list[dict]: ...
diff --git a/openrag/core/ports/user_repo.py b/openrag/core/ports/user_repo.py
new file mode 100644
index 000000000..0e7982a23
--- /dev/null
+++ b/openrag/core/ports/user_repo.py
@@ -0,0 +1,50 @@
+"""User repository interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from typing import Any
+
+from openrag.core.models.user import User, UserPartition
+
+
+class UserRepository(ABC):
+    """CRUD operations for users and partition memberships."""
+
+    @abstractmethod
+    async def create_user(self, user: User) -> User: ...
+
+    @abstractmethod
+    async def get_user(self, user_id: int) -> User | None: ...
+
+    @abstractmethod
+    async def get_user_by_token(self, token_hash: str) -> User | None: ...
+
+    @abstractmethod
+    async def get_user_by_external_id(self, external_id: str) -> User | None: ...
+
+    @abstractmethod
+    async def list_users(self, offset: int = 0, limit: int = 50) -> list[User]: ...
+
+    @abstractmethod
+    async def update_user(self, user_id: int, **fields: Any) -> User | None: ...
+
+    @abstractmethod
+    async def delete_user(self, user_id: int) -> bool: ...
+
+    # ── Partition memberships ─────────────────────────────────────────
+
+    @abstractmethod
+    async def assign_partition(self, assignment: UserPartition) -> UserPartition: ...
+
+    @abstractmethod
+    async def remove_partition(self, user_id: int, partition: str) -> bool: ...
+
+    @abstractmethod
+    async def list_user_partitions(self, user_id: int) -> list[UserPartition]: ...
+
+    @abstractmethod
+    async def list_partition_users(self, partition: str) -> list[UserPartition]: ...
+
+    @abstractmethod
+    async def update_partition_role(self, user_id: int, partition: str, role: str) -> bool: ...
diff --git a/openrag/core/rerankers/__init__.py b/openrag/core/rerankers/__init__.py
index e69de29bb..f27129c2a 100644
--- a/openrag/core/rerankers/__init__.py
+++ b/openrag/core/rerankers/__init__.py
@@ -0,0 +1,6 @@
+"""Reranker ABC + registry."""
+
+from openrag.core.rerankers.registry import reranker_registry
+from openrag.core.rerankers.reranker import Reranker
+
+__all__ = ["Reranker", "reranker_registry"]
diff --git a/openrag/core/rerankers/registry.py b/openrag/core/rerankers/registry.py
new file mode 100644
index 000000000..103feef02
--- /dev/null
+++ b/openrag/core/rerankers/registry.py
@@ -0,0 +1,6 @@
+"""Reranker registry."""
+
+from openrag.core.rerankers.reranker import Reranker
+from openrag.core.utils.registry import Registry
+
+reranker_registry: Registry[Reranker] = Registry("reranker")
diff --git a/openrag/core/rerankers/reranker.py b/openrag/core/rerankers/reranker.py
new file mode 100644
index 000000000..9f2ea60da
--- /dev/null
+++ b/openrag/core/rerankers/reranker.py
@@ -0,0 +1,17 @@
+"""Abstract reranker interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+
+class Reranker(ABC):
+    """Base class for all reranking providers."""
+
+    @abstractmethod
+    async def rerank(self, query: str, documents: list[str], top_k: int | None = None) -> list[tuple[int, float]]:
+        """Rerank documents for a query.
+
+        Returns list of (original_index, score) sorted by relevance.
+        """
+        ...
diff --git a/openrag/core/vector_stores/__init__.py b/openrag/core/vector_stores/__init__.py
index e69de29bb..501aa1d4d 100644
--- a/openrag/core/vector_stores/__init__.py
+++ b/openrag/core/vector_stores/__init__.py
@@ -0,0 +1,5 @@
+"""VectorStore ABC."""
+
+from openrag.core.vector_stores.vector_store import VectorStore
+
+__all__ = ["VectorStore"]
diff --git a/openrag/core/vector_stores/vector_store.py b/openrag/core/vector_stores/vector_store.py
new file mode 100644
index 000000000..221d5c0c3
--- /dev/null
+++ b/openrag/core/vector_stores/vector_store.py
@@ -0,0 +1,63 @@
+"""Abstract vector store interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from typing import Any
+
+from openrag.core.models.chunk import Chunk
+
+
+class VectorStore(ABC):
+    """Base class for vector database backends."""
+
+    @abstractmethod
+    async def upsert(self, chunks: list[Chunk], collection: str = "default") -> int:
+        """Insert or update chunks. Returns count of upserted items."""
+        ...
+
+    @abstractmethod
+    async def search(
+        self,
+        embedding: list[float],
+        top_k: int = 10,
+        collection: str = "default",
+        filters: dict[str, Any] | None = None,
+    ) -> list[dict[str, Any]]:
+        """Search by embedding vector. Returns raw results."""
+        ...
+
+    @abstractmethod
+    async def delete(self, ids: list[str], collection: str = "default") -> int:
+        """Delete chunks by ID. Returns count of deleted items."""
+        ...
+
+    @abstractmethod
+    async def ensure_collection(self, name: str, dimension: int, **kwargs: Any) -> None:
+        """Create collection if it doesn't exist."""
+        ...
+
+    @abstractmethod
+    async def drop_collection(self, name: str) -> None:
+        """Drop a collection entirely."""
+        ...
+
+    @abstractmethod
+    async def collection_exists(self, name: str) -> bool:
+        """Check if collection exists."""
+        ...
+
+    @abstractmethod
+    async def query_ids_by_filter(self, collection: str, filters: dict[str, Any]) -> list[str]:
+        """Return chunk IDs matching the given filter expression."""
+        ...
+
+    @abstractmethod
+    async def query_chunks_by_filter(
+        self,
+        collection: str,
+        filters: dict[str, Any],
+        output_fields: list[str] | None = None,
+    ) -> list[dict[str, Any]]:
+        """Return full chunk data matching the given filter expression."""
+        ...
diff --git a/openrag/core/vlm/__init__.py b/openrag/core/vlm/__init__.py
index e69de29bb..b562bec80 100644
--- a/openrag/core/vlm/__init__.py
+++ b/openrag/core/vlm/__init__.py
@@ -0,0 +1,6 @@
+"""VLM ABC + registry."""
+
+from openrag.core.vlm.registry import vlm_registry
+from openrag.core.vlm.vlm import VLM
+
+__all__ = ["VLM", "vlm_registry"]
diff --git a/openrag/core/vlm/registry.py b/openrag/core/vlm/registry.py
new file mode 100644
index 000000000..91d57dce9
--- /dev/null
+++ b/openrag/core/vlm/registry.py
@@ -0,0 +1,6 @@
+"""VLM registry."""
+
+from openrag.core.utils.registry import Registry
+from openrag.core.vlm.vlm import VLM
+
+vlm_registry: Registry[VLM] = Registry("vlm")
diff --git a/openrag/core/vlm/vlm.py b/openrag/core/vlm/vlm.py
new file mode 100644
index 000000000..2da69b6d7
--- /dev/null
+++ b/openrag/core/vlm/vlm.py
@@ -0,0 +1,19 @@
+"""Abstract VLM (Vision-Language Model) interface."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+
+class VLM(ABC):
+    """Base class for all vision-language model providers."""
+
+    @abstractmethod
+    async def caption_image(self, image_bytes: bytes, prompt: str | None = None) -> str:
+        """Generate a caption/description for an image."""
+        ...
+
+    @abstractmethod
+    async def caption_images_batch(self, images: list[bytes], prompt: str | None = None) -> list[str]:
+        """Batch caption multiple images."""
+        ...