# How to Fix Placeholder Mismatches

> Understand and resolve the Param validation badge: when a placeholder like {name} or %@ is missing or wrong in a translation.

Source: https://stringlane.app/docs/fix-placeholder-mismatches
Last updated: 2026-08-19

A **Param** badge (red) appears when a placeholder in the base locale doesn't match what's in the target translation. This is a hard error: at runtime, a missing placeholder means the variable value is silently dropped from the displayed string.

## What counts as a placeholder

StringLane treats these as placeholders, depending on your file format:

| Format | Placeholder syntax |
|---|---|
| ARB / Flutter | `{name}`, `{count}` |
| iOS .strings | `%@`, `%d`, `%1$@`, `%2$d` |
| Android XML | `%s`, `%d`, `%1$s` |
| i18next JSON | `{{name}}`, `{{count}}` |
| ICU MessageFormat | `{name, plural, ...}`, `{gender, select, ...}` |

## Finding out which placeholder is wrong

Two places tell you:

- **Hover the red Param badge.** The tooltip names the placeholder that is missing from the target, or the extra one that appears in the target but not the base.
- **Read the [Issues Panel](/docs/use-issues-panel)** (⌘J). Each mismatch is its own row, naming the key, the locale and the specific placeholder — no hovering, and you can work down the list.

![The French cell for homeWelcomeBack reads Bon retour ! and carries a red PARAM badge, while the English source above it reads Welcome back, {name}! — the placeholder is missing from the translation](/docs-screenshots/param-badge-with-tooltip.webp)

## The one-click fix

When StringLane can reconstruct the correct string on its own, a 🔧 **wrench** button appears next to the Param badge. Click it and the placeholder is restored in place.

This is a deterministic repair, not an AI call: it is instant, free, and produces the same result every time. Reach for it first — the manual and AI routes below are for the cases where the wrench does not appear.

## Fixing the mismatch manually

1. Click the cell to edit it.
2. Add the missing placeholder in the correct position within the translated string.
3. For ARB, placeholders are case-sensitive and must match exactly: `{userName}` ≠ `{username}`.
4. Press Enter to confirm. The Param badge clears immediately if the fix is correct.

**Example:**
- Base (English): `Hello, {name}! You have {count} messages.`
- Broken Spanish: `¡Hola! Tienes mensajes.`
- Fixed Spanish: `¡Hola, {name}! Tienes {count} mensajes.`

## Fixing with AI re-translation

Click ✨ on the Param cell to re-translate it. The AI is given a hard instruction to preserve all placeholders in the correct format. In most cases, this produces a clean result without the mismatch.

If re-translation still produces a mismatch (rare, usually on complex ICU strings), edit the cell manually.

## Param autofix

For simple cases where the only issue is a missing placeholder at the end of a string, StringLane may offer an **Autofix** option directly on the badge. Click the badge → click **Autofix** → the placeholder is appended to the translation automatically.

Autofix is a heuristic: review the result to ensure the placeholder is in the grammatically correct position for the target language.

## Preventing param mismatches

- **Use AI translation** with product context: the AI is explicitly instructed to preserve placeholders.
- **Add `@description` to ARB keys** with variables: the description is passed to the AI, giving more context for correct placeholder placement.
- **Review translated strings with variables** after bulk translation: filter by Issues (⌘⇧I) to find Param badges quickly.