Glossary
Terms used across Twilic documentation, specification, and SDK APIs.
A–C
Base snapshot
A full encoded message stored in session state as the reference point for subsequent patches. Identified by base_id.
Batch profile
Encoding mode that groups multiple same-shape records into one message with shared shape and string tables.
Bound profile
Schema-aware encoding mode. In v3 compact layouts, field names, field numbers, type tags, and per-field fallback mode bytes are omitted from field payloads; positions are defined by a Schema.
BOUND_STREAM: v3 envelope kind 0x0F that binds one schema for consecutive compact record bodies.
col_batch
Columnar batch message kind. Each field encoded as an independent column with per-column codec.
Columnar batch
See Batch & Columnar.
Control message
Session-level instruction (register keys, reset state, register shape) sent on stateful channels.
D–I
Dynamic profile
Default schema-less encoding. Self-describing values; no cross-message state.
Extension (ext)
Application-defined binary payload with type code. Similar to MessagePack ext types.
Interning
Sending a value (shape, key name, or string) once per message and referencing by ID thereafter.
Key interning
Field names sent once in a shape definition, referenced by shape ID in subsequent objects.
M–P
Message
Low-level wire-level unit (scalar, batch, patch, control, etc.). See Spec — Format.
MessagePack
Binary JSON-like format. Twilic's closest predecessor for schema-less use cases.
Patch / state patch
Stateful message sending only changed fields relative to a base snapshot or previous message.
Profile
Encoding strategy: Dynamic, Batch, Bound, or Stateful. See Encoding Profiles.
Protobuf
Google's schema-first binary format. Strong alternative for gRPC and strict contracts.
R–S
Reference profile
Normative current encoding rules. See v3 Reference Profile.
Row batch
Batch mode encoding records row-by-row with shared shape. Wire kind: row_batch.
Schema
Field definition for Bound profile: field numbers, names, types, constraints.
SCHEMA_BATCH: v3 envelope kind 0x0E for schema-aware columnar batches.
Session encoder
Encoder maintaining state across an ordered message sequence for patches and dictionaries.
Shape
Ordered set of field names defining an object structure. Registered once and referenced by shape_id.
Shape interning
Sending shape definition once per batch; objects reference shape by ID.
Stateful profile
Encoding mode using session state for patches, trained dictionaries, and template batches.
String interning
Repeated string values sent once per message; subsequent occurrences use string ID.
T–Z
Template batch
Batch reusing a previously registered column template. Efficient when column structure repeats.
Trained dictionary
Session-scoped string dictionary learned across messages for repeated values.
Transport JSON
Intermediate JSON representation preserving Twilic types (bigint, Uint8Array). Used by JS advanced API.
TwilicValue
Dynamic value type: null, bool, number, bigint, string, binary, array, map.
Typed vector
Homogeneous array encoded with a specialized codec (delta bitpack, XOR float, RLE).
UnknownReferencePolicy
Behavior when decoder sees unknown base/shape/dictionary ID: failFast or statelessRetry.
v2
Current Twilic release line. Clean break from v1.
Wire tag
First byte(s) identifying value type and encoding family. See Wire Tags.