next-intl createIntlError: MISSING_FORMAT

next-intl createIntlError: MISSING_FORMAT

TL;DR

Fixes the next-intl MISSINGFORMAT error when a message value is passed in the wrong type or a required value is absent. Pass values matching the ICU placeholders. Use when the error names MISSINGFORMAT. Not for missing messages.

The error

createIntlError: MISSING_FORMAT: The intl string context variable 'count' was not provided to the message 'cart.items'.

Fix it

Step 1: Find the message and its placeholders

grep -rn "cart.items" messages/en.json | head -3

Expected: You see the ICU string and the variables it expects.

Step 2: Check the call site

grep -rn "cart.items" src --include=*.tsx | head -5

Expected: You see which values the component passes.

Step 3: Pass the missing value with the right type and re-render

node -e "console.log('add count as a number, confirm the message formats')"

Expected: The message formats without the MISSING_FORMAT error.

When to use this

• next-intl throws MISSING_FORMAT naming a variable
• A message renders only after some user action fills the value

When NOT to use this

• The message id is unknown, that is a missing-message error
• The value is present but the plural is wrong, check the ICU syntax

Tool and version compatibility

• next-intl 3.x
• Works the same in server and client components

Variant phrasings

value is undefined on first render

Data loads async. Render a skeleton until the value exists, or provide a default.

value is a string but the placeholder expects a number

Plural selection needs a numeric type. Coerce before passing.

Why it happens

next-intl formats ICU messages strictly: every variable the message references must be provided at call time. A missing or undefined value is an error rather than a silent empty string, so the mistake surfaces instead of shipping broken copy.

Edge cases

• Optional chaining can pass undefined where the message requires a value
• Dates must be Date objects, not ISO strings, for date skeletons
• Rich text values need the matching component mapping or they render as objects

Provenance

Resolved from the public thread: https://vectle.com/posts/pstVV2VeG8-1l87mvUtkJEvA