which will not. Over time, more of the API will fall under the stability guarantees. Thus, APIs can be categorized in the following 2 broad categories:
***public APIs**, for which API/`ABI <https://en.wikipedia.org/wiki/Application_binary_interface>`_ backwards compatibility guarantees are provided. See: :ref:`public-api`
***non-public APIs**, for which no backwards compatibility guarantees are provided. See: :ref:`non-public-api`
The following modules form part of Corda's public API and we commit to API/ABI backwards compatibility in following releases, unless an incompatible change is required for security reasons:
***Core (net.corda.core)**: core Corda libraries such as crypto functions, types for Corda's building blocks: states, contracts, transactions, attachments, etc. and some interfaces for nodes and protocols
The following modules are not part of the Corda's public API and no backwards compatibility guarantees are provided. They are further categorized in 2 classes:
* the incubating modules, for which we will do our best to minimise disruption to developers using them until we are able to graduate them into the public API
* the unstable modules, which are available but we do not commit to their stability or continuation in any sense
***net.corda.finance**: a range of elementary contracts (and associated schemas) and protocols, such as abstract fungible assets, cash, obligation and commercial paper
***net.corda.buildSrc**: necessary gradle plugins to build Corda
***net.corda.node**: core code of the Corda node (eg: node driver, node services, messaging, persistence)
***net.corda.node.api**: data structures shared between the node and the client module, e.g. types sent via RPC
***net.corda.samples.network.visualiser**: a network visualiser that uses a simulation to visualise the interaction and messages between nodes on the Corda network
***net.corda.samples.demos.attachment**: demonstrates sending a transaction with an attachment from one to node to another, and the receiving node accessing the attachment
***net.corda.samples.demos.bankofcorda**: simulates the role of an asset issuing authority (eg. central bank for cash)
***net.corda.samples.demos.irs**: demonstrates an Interest Rate Swap agreement between two banks
***net.corda.samples.demos.notary**: a simple demonstration of a node getting multiple transactions notarised by a distributed (Raft or BFT SMaRt) notary
***net.corda.samples.demos.trader**: demonstrates four nodes, a notary, an issuer of cash (Bank of Corda), and two parties trading with each other, exchanging cash for a commercial paper
***net.corda.node.smoke.test.utils**: test utilities for smoke testing
***net.corda.node.test.common**: common test functionality
***net.corda.tools.demobench**: a GUI tool that allows to run Corda nodes locally for demonstrations
***net.corda.tools.explorer**: a GUI front-end for Corda
***net.corda.tools.graphs**: utilities to infer project dependencies
***net.corda.tools.loadtest**: Corda load tests
***net.corda.webserver**: is a servlet container for CorDapps that export HTTP endpoints. This server is an RPC client of the node
***net.corda.sandbox-creator**: sandbox utilities
***net.corda.quasar.hook**: agent to hook into Quasar and provide types exclusion lists
..warning:: Code inside any package in the ``net.corda`` namespace which contains ``.internal`` or in ``net.corda.node`` for internal use only.
Future releases will reject any CorDapps that use types from these packages.
..warning:: The web server module will be removed in future. You should call Corda nodes through RPC from your web server of choice e.g., Spring Boot, Vertx, Undertow.
