Glossary Updates6 new terms added to the glossaries · October 11, 2026, 13:38 CEST
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Glossary · 4 · Platform SDKs and extensions

App manifest

Also known as: Extension manifest, Application manifest, Manifest file

In software engineering, an app manifest is a declarative file, usually in JSON or XML, that describes an app or extension to the platform that hosts it: its identity and version, the host versions it supports, its entry points, the functionality it contributes and the permissions or scopes it requests.

  • Platform SDK
  • Extension models

In one sentence

An app manifest is a declarative file that tells a host platform what an app or extension is, what it contributes and which permissions it needs.

Example

An editor extension's manifest names the publisher, a semantic version, the supported editor versions, the command it adds to the menu and the event that activates it.

How it applies

  • Platform SDKs: The manifest is how an extension introduces itself to the host. The host reads it to decide whether the extension is compatible, when to load it and where its contributions go. In Visual Studio Code, for example, the manifest is the extension's package.json with required fields such as name, version, publisher and engines (the compatible editor versions) and optional fields such as main (the entry point), contributes and activationEvents.
  • Permissions and scopes: Many platforms take the requested permissions from the manifest, show them to the user or administrator and enforce them at run time; Chrome extensions declare them in manifest.json. A manifest that asks for more than the extension needs widens what it can reach.
  • Developer SDKs: Cloud and SaaS platforms that host third-party apps use the same pattern to declare OAuth scopes, webhook subscriptions and callback URLs, so the manifest and the authorization model are documented together.
  • Web apps: The W3C Web Application Manifest defines a JSON-based file with metadata about a web application, such as its name, icons and start URL. As of October 11, 2026 it is a W3C Working Draft, not a Recommendation.
  • Documentation: The manifest is part of the interface contract between host and extension. Its fields, their allowed values and the host versions that introduced them belong in the reference documentation; samples should ship with a manifest that validates against the current schema.

App manifest vs. package metadata

Package metadata (for a package manager) describes how to find, install and resolve the dependencies of a package. An app manifest describes how a running host should treat the extension. Some ecosystems keep both in one file, which is why the two are often confused; the host-specific fields are the manifest part.

External references