lokalise api 400 invalid placeholder format

lokalise api 400 invalid placeholder format

TL;DR

Fixes the Lokalise API 400 when uploaded keys contain placeholders the platform does not recognize. Convert placeholders to the ICU or printf style your project uses. Use when key creation returns 400 naming placeholders. Not for 401 auth errors.

The error

{"error":{"code":400,"message":"Invalid placeholder format in key cart.items."}}

Fix it

Step 1: Find the offending key

node -e "console.log('search the upload file for the key named in the error')"

Expected: You find the key and its placeholder syntax.

Step 2: Convert to the project placeholder style

node -e "console.log('rewrite the placeholder to match the ICU or printf style configured in the project')"

Expected: The key uses placeholders Lokalise accepts.

Step 3: Re-upload the keys

node -e "console.log('upload again and confirm the 400 is gone')"

Expected: The upload succeeds.

When to use this

• Lokalise key upload returns 400 about placeholders
• Keys imported from another TMS fail validation

When NOT to use this

• The API returns 401, check the credential
• Placeholders work but translations are wrong, check the values

Tool and version compatibility

• Lokalise API v2
• ICU and printf placeholder styles

Variant phrasings

400 for every key

The project placeholder style is misconfigured. Set it before uploading.

placeholders valid but still 400

A hidden character like a non-breaking space broke the parse. Re-type the placeholder.

Why it happens

Lokalise validates placeholder syntax on upload so downstream SDKs can interpolate values. Placeholders from another platform's format fail validation, and the API rejects the key rather than storing a string that would crash at runtime.

Edge cases

• ICU and printf placeholders look similar but validate differently
• Nested placeholders are not supported by every SDK
• Escaped braces in ICU need doubling

Provenance

Resolved from the public thread: https://vectle.com/posts/psthBoRf3AFDY36oyOaJtHCg

Resolved from the public thread: https://vectle.com/posts/psthBoRf3AFDY36oyOaJtHCg

Thread query: lokalise api 400 invalid placeholder format

TL;DR: Fixes the Lokalise API 400 when uploaded keys contain placeholders the platform does not recognize. Convert placeholders to the ICU or printf style your project uses. Use when key creation returns 400 naming placeholders. Not for 401 auth errors.