Grida I/O — .grida Format & Loading (TS side)

Format Overview

Grida uses FlatBuffers as the canonical binary format. File identifier: "GRID".

Two on-disk variants:

Variant	Detection	Notes
Raw FlatBuffers	"GRID" at bytes 4–7	Bare document, no images
ZIP archive	ZIP magic bytes	manifest.json + document.grida + images/

Document model: Flat node repository (not nested). Nodes reference parents via ID + fractional-index position strings. Multi-scene: each Figma page → a SceneNode.

Key Locations

Path	Role
packages/grida-canvas-schema/grida.ts	TS runtime types (grida namespace) + SCHEMA_VERSION
packages/grida-canvas-io/	TS file loading, archive pack/unpack, clipboard protocol
packages/grida-format/src/	FROZEN flatc TS bindings (tombstone — see below)

The schema source of truth and the Rust decoder live in the engine repo: format/grida.fbs · crates/grida/src/io/.

TS Side — packages/grida-canvas-io/

• io.load(file) — auto-detects format, decodes, extracts images → LoadedDocument
• io.is_grid(bytes) — checks "GRID" identifier
• io.archive.pack/unpack — ZIP with manifest.json
• io.clipboard.encode/decode — Grida clipboard protocol

The tombstone — packages/grida-format

The generated TS FlatBuffers bindings are committed and frozen: the flatc generator wiring was deleted at the engine split (this repo has no format/grida.fbs and no bin/activate-flatc). The bindings are byte-identical to pinned flatc v25.12.19 output and the formatter/linter ignore them to keep it that way. Do not edit them. If the schema evolves in the engine repo and this reader should follow, re-snapshot deliberately from a gridaco/nothing checkout.

Verification

pnpm turbo test --filter='@grida/io'
pnpm turbo typecheck --filter='@grida/io' --filter='@grida/canvas-schema'

Schema Changes

Schema evolution happens in the engine repo (see its io-grida skill and format/AGENTS.md). What this repo owes on a breaking change — a cross-REPO lockstep:

1. TS: bump grida.program.document.SCHEMA_VERSION in packages/grida-canvas-schema/grida.ts to match the engine's SCHEMA_VERSION in crates/grida/src/io/io_grida_fbs.rs — exactly in sync; both writers must emit the same version string.
2. Re-snapshot the frozen bindings from the new schema (deliberate act, see above).
3. Old files are rejected by the TS reader (format.ts calls isSchemaCompatible() and throws on mismatch).

Version compatibility logic (isSchemaCompatible in grida-canvas-schema/grida.ts):

• While MAJOR=0: same MAJOR.MINOR required (e.g. 0.91.* accepts 0.91.*, rejects 0.90.*)
• Once MAJOR≥1: same MAJOR required (standard semver)

Format: MAJOR.MINOR.PATCH-prerelease+build (e.g. "0.91.0-beta+20260311").

Note: the TS FlatBuffers decoder is more lenient than the Rust verifier — a TS-side round-trip may pass on structurally invalid bytes. For byte-level verification, use the engine repo's Rust verifier.