airbnb/lottie-android · error · JsonDataException

Expected a string but was {} at path {}

Error message

Expected a string but was {} at path {}

What it means

JsonUtf8Reader.nextString() peeks the next token expecting a string-compatible value: double-quoted, single-quoted, buffered, or a number/long that can be coerced to string. Any other token type (boolean, null, object start, array start, EOF) triggers JsonDataException. This fires when the parser reads a string-typed property (e.g., layer name, refId, font family) but the JSON contains a non-string value.

Source

Thrown at lottie/src/main/java/com/airbnb/lottie/parser/moshi/JsonUtf8Reader.java:633

    if (p == PEEKED_NONE) {
      p = doPeek();
    }
    String result;
    if (p == PEEKED_UNQUOTED) {
      result = nextUnquotedValue();
    } else if (p == PEEKED_DOUBLE_QUOTED) {
      result = nextQuotedValue(DOUBLE_QUOTE_OR_SLASH);
    } else if (p == PEEKED_SINGLE_QUOTED) {
      result = nextQuotedValue(SINGLE_QUOTE_OR_SLASH);
    } else if (p == PEEKED_BUFFERED) {
      result = peekedString;
      peekedString = null;
    } else if (p == PEEKED_LONG) {
      result = Long.toString(peekedLong);
    } else if (p == PEEKED_NUMBER) {
      result = buffer.readUtf8(peekedNumberLength);
    } else {
      throw new JsonDataException("Expected a string but was " + peek() + " at path " + getPath());
    }
    peeked = PEEKED_NONE;
    pathIndices[stackSize - 1]++;
    return result;
  }

  @Override public boolean nextBoolean() throws IOException {
    int p = peeked;
    if (p == PEEKED_NONE) {
      p = doPeek();
    }
    if (p == PEEKED_TRUE) {
      peeked = PEEKED_NONE;
      pathIndices[stackSize - 1]++;
      return true;
    } else if (p == PEEKED_FALSE) {
      peeked = PEEKED_NONE;
      pathIndices[stackSize - 1]++;

View on GitHub (pinned to 05ea92e903)

Solutions

1. Use the exception path to locate the field and ensure its value is a JSON string.
2. Validate the animation with LottieFiles validator.
3. Re-export or re-download the animation.

LottieTask<LottieComposition> task = LottieCompositionFactory.fromAsset(context, name);
task.addListener(result -> { /* success */ })
     .addFailureListener(e -> { /* JSON string type error */ });

When it happens

Trigger: A property expected to be a string (e.g., 'nm' layer name, 'refId', 'fFamily' font family) is instead a number, boolean, null, object, or array in the Lottie JSON.

Common situations: Malformed Lottie JSON where a string field contains a non-string value; non-standard export tool; corrupted or hand-edited file.

Related errors

• Expected BEGIN_ARRAY but was {} at path {}
• Expected END_ARRAY but was {} at path {}
• Expected BEGIN_OBJECT but was {} at path {}
• Expected END_OBJECT but was {} at path {}
• Expected a name but was {} at path {}

AI-assisted analysis of airbnb/lottie-android@05ea92e903 (2026-08-14). Data as JSON: /api/errors/5359234c7ebafc9a. Report an issue: GitHub.