n8n-binary-and-data
n8n Binary and Data
n8n handles two kinds of data: JSON (in $json) and binary (in $binary), flowing side-by-side. Binary has sharp edges around agent tools, storage, and display contexts (e.g., chat hub).
For tabular storage (Data Tables), see the n8n-data-tables skill.
Non-negotiables
- Binary is in
$binary, not$json. Don't read file contents from$json. - Binary cannot cross the agent tool boundary in either direction. Tool parameters are JSON only (via
fromAi()), and tool results are JSON only. Pre-stage binary in storage and pass keys/URLs through JSON. The agent'spassthroughBinaryImages: truelets the LLM see uploaded images for vision, but it does NOT enable tools to receive them. Seereferences/AGENT_TOOL_BINARY.md.
Strong defaults
- Merge nodes keep binary in context. When a side computation strips binary, merge it back rather than re-fetching. See
references/MERGE_FOR_CONTEXT.md.
Binary basics
In n8n, each item has two slots:
More from n8n-io/skills
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Use when working with n8n's built-in Data Tables, designing schemas, inserting/updating/upserting rows, deduping, or querying. Triggers on "Data Table", "data table", `n8n-nodes-base.dataTable`, "dedup", "idempotency", "lookup", "persistent state", "store across executions", or any schema design discussion inside n8n.
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