---
url: "https://vueda.dev/v3/core-concepts/index.md"
title: "Core Concepts"
---

# Core Concepts

Core Concepts explains the "why" behind VUEDA defaults and the contracts that let server and client work together predictably.

## System Foundations

- [Architecture Overview](/v3/core-concepts/architecture-overview.md): Layers, boundaries, and main extension points.
- [Canonical Registration and Model Discovery](/v3/core-concepts/canonical-registration-and-discovery.md): Why models are registered and how info endpoints discover them.
- [Contract-First Dynamic UI](/v3/core-concepts/contract-first-dynamic-ui.md): Why UI is driven by server metadata rather than hardcoded forms.
- [Model Feature Policy](/v3/core-concepts/model-feature-policy.md): How `class Vueda` declares which framework features a model participates in.

## Data and API Contracts

- [Server-Client Metadata Contract](/v3/core-concepts/server-client-metadata-contract.md): Model fields, actions, expands, filters, ordering, permissions.
- [Field and Expand Semantics](/v3/core-concepts/field-and-expand-semantics.md): Meaning of serializer fields, expandable relations, and sparse responses.
- [Filtering and Ordering Semantics](/v3/core-concepts/filtering-and-ordering-semantics.md): How server filtersets/ordering shape client query controls.
- [Error and Validation Contract](/v3/core-concepts/error-and-validation-contract.md): Validation payload shapes, `non_field_errors`, and client form handling.
- [Primary Key and Identifier Discipline](/v3/core-concepts/pk-and-identifier-discipline.md): Expected identifier formats and conversion across Python/JS boundaries.
- [Model History Response](/v3/core-concepts/model-history-response.md): Which events an object's history includes, who sees them, and how they group into actions.

## Compatibility and Boundaries

- [DRF Ecosystem Compatibility Boundaries](/v3/core-concepts/drf-ecosystem-deviations.md): Hub for where VUEDA intentionally constrains or extends DRF-ecosystem defaults to preserve a contract-first, metadata-driven system.
- [Nested Write Compatibility](/v3/core-concepts/nested-write-compatibility.md): How flex-fields and nested-writable behavior is composed and constrained for nested writes.

## Authorization and Behavior

- [Permission Model (CRUDL + Object + State)](/v3/core-concepts/permission-model.md): Full permission evaluation model in VUEDA.
- [Authorization vs UI Semantics](/v3/core-concepts/authorization-vs-ui-semantics.md): Why UI visibility and route semantics differ from server authorization, including why client-side Django-permission evaluation is not authoritative.
- [Action Contract and Availability](/v3/core-concepts/action-contract-and-availability.md): `available_actions`, route actions, group filtering, and safe fallback behavior.
- [Workflow as a Permission Overlay](/v3/core-concepts/workflow-permission-overlay.md): State permissions, transition permissions, and row-level outcomes.
- [Row-Level Permission Filtering](/v3/core-concepts/row-level-permission-filtering.md): Queryset/object checks and `list` filtering guarantees.

## Client Runtime Model

- [Reactive Data Flow (Stores + Composables)](/v3/core-concepts/reactive-data-flow.md): How stores/composables coordinate model info, config, and object data.
- [Cancellable Network Operations](/v3/core-concepts/cancellable-network-operations.md): Why cancellation is built into CRUDL and fetch helpers.
- [Form State and Validation Lifecycle](/v3/core-concepts/form-state-and-validation-lifecycle.md): Client-side form graph, touched/modified/ignored state, and server error integration.
- [Routing and View Resolution Model](/v3/core-concepts/routing-and-view-resolution-model.md): How CRUDL routes and action routing resolve to concrete components.
- [Theming and Customization](/v3/core-concepts/theming-and-customization.md): The four-scope model (instance, component, family, brand) and the mechanisms that map to each.

## Operational Concepts

- [Configuration Surface and Defaults](/v3/core-concepts/configuration-surface-and-defaults.md): VUEDA defaults, required settings, and security-sensitive options.
- [VDQ and Background Work Model](/v3/core-concepts/vdq-and-background-work.md): Queue item lifecycle, transition hooks, and async execution boundaries.