Codec

The Encoder and Decoder abstracts — Invocable contracts that every concrete stream codec implements. Format-specific codec modules (plain-text-codec, ndjson-codec, octet-codec, sse-codec) extend these so downstream consumers can write transport-neutral pipelines.

Why use this

• Transport-neutral — write once against Codec.Encoder / Codec.Decoder; swap the backing format at the import boundary without touching consumer manifests.
• Stream-first — both abstracts operate on AsyncIterable<Uint8Array> (encoder output) and AsyncIterable<T> (decoder output), so memory stays bounded for large payloads.
• Composes with Run.Sequence — codec invocations slot into pipelines like any other step.

Kinds (abstracts)

Kind	Purpose
Codec.Encoder	Abstract: encode an async iterable of records into a byte stream.
Codec.Decoder	Abstract: decode a byte stream into an async iterable of records (or a single value).

These are abstracts, not runnable resources — concrete codec modules implement them.

Example

A consumer reads Codec.Encoder polymorphically:

kind: Telo.Application
metadata: { name: codec-stream, version: 1.0.0 }
imports:
  Codec: std/codec@latest
  Ndjson: std/ndjson-codec@latest
---
kind: Http.Server
metadata: { name: Stream }
encoders:
  application/x-ndjson: { kind: Ndjson.Encoder, name: Out }