Shopify JSON Metafield Size Checker
Check a JSON metafield's real, minified size against Shopify's 128KB limit before you save it.
- Pasted size
- 206 B
- Minified size
- 179 B
- Of the limit
- 0%
- Limit
- 128 KB
- Valid JSON
- Under the size limit130,893 bytes of headroom.
- Whitespace is inflating the pasted sizeMinifying alone saves 27 bytes. Shopify stores the value as JSON, so pretty-printing costs you nothing once it's saved, but paste the minified version if you're close to the limit and testing by hand.
Minified JSON
{"sizes":["S","M","L","XL"],"care":"Machine wash cold, tumble dry low.","material":{"cotton":95,"elastane":5},"highlights":["Pre-shrunk","OEKO-TEX certified","Fair trade cotton"]}
This is the exact byte count Shopify checks against the limit.
The limits
| Metafield type | Value size limit |
|---|---|
| json | 128 KB (131,072 bytes) |
| Most other types (text, rich text, and so on) | 64 KB (65,536 bytes) |
| id, url | 2 KB |
List metafields can hold up to 128 items (metaobject reference lists up to 1,024), and each item follows the same per-type size limit as a single value of that type.
Shopify measures the size of what it actually stores, which is the minified JSON, not however you pasted it with indentation. Pretty-printing while you edit costs nothing once it's saved, but if you're close to the limit, check the minified size, which is what this tool compares against the limit.
If it's too big
- Split it into two or more metafields grouped by topic, instead of one large blob
- Move repeating structured data (like a list of specs or variants) into a metaobject and reference it instead of embedding the data directly
- Drop fields your theme never actually reads
Questions people ask
Why is my pasted size bigger than the minified size?
Indentation and line breaks count as bytes too. This tool shows both, but only the minified size matters for the limit, since that's what Shopify actually stores.
Does this apply to metaobject fields too?
The same per-type size limits apply to metaobject field values, though this checker is written against a single JSON metafield's limit specifically.
I'm nowhere near 128KB but Shopify still rejects it. Why?
Check that the JSON is valid first, since a malformed value is rejected regardless of size. This tool validates the JSON and shows the exact parse error if there is one.
Can I go over the limit if I built the app before the change?
Shopify grandfathered JSON metafields already using more than 128KB before the limit changed, up to a higher cap, but any new value is checked against 128KB. If you're unsure which applies to you, check with Shopify support.
Related tools
Want this builtinto your store?
I'm Emmanuel, a Shopify and WooCommerce developer. If this tool pointed at something you'd rather have fixed for you (a faster store, cleaner product data, a migration, a custom feature), send me a note.
Emmanuel Asika
Shopify & WooCommerce developer, Dublin
I build and fix online stores: new builds, migrations, speed, SEO and the custom bits apps can't do.
Last reviewed 30 September 2026.