encodable

Encodable is an adjective used in computing to describe data, objects, or values that can be converted into a serialized form, suitable for storage or transmission. Encoding maps a program-level representation into a sequence of bytes or characters with an encoder, while decoding reverses the process to reconstruct the original value. Encodability is fundamental to data persistence, network communication, and inter-process interaction. Common encodings include JSON, XML, YAML, binary formats, and platform-specific schemes such as Protocol Buffers and MessagePack.

In many programming languages, types or values declare encodability by implementing an interface or protocol. In Swift, the Encodable protocol marks types whose instances can be encoded by encoders such as JSONEncoder or PropertyListEncoder. The companion Decodable protocol, together with Encodable, forms Codable. Similar concepts exist in other ecosystems: Java’s Serializable, Python’s pickle and json, and .NET’s ISerializable. Encodable types typically provide a method to write their fields to an encoder; decoders perform the reverse operation, mapping encoded data back to values.

Encoding introduces choices about schema, data types, field names, and versioning. Some encodings are schema-based, providing strict validation, while others are schema-less. Endianness, character encoding, and preservation of type information affect interoperability. Security concerns include validating input during decoding to avoid data corruption or code execution vulnerabilities.

See also: Codable, Decodable, Serialization.