---
title: JSON
description: JSON is stored indented by two spaces, properties in the order they were written, numbers as written and non-ASCII text unescaped. It is compared as a...
url: https://docs-v3-preview.elastic.dev/formats/json
---

# JSON
```csharp
using Nullean.Snapshots.Json;

responseBody.Should().MatchJsonSnapshot();                                    
product.Should().MatchJsonSnapshot(AppJsonContext.Default.Product);           
product.Should().MatchJsonSnapshot(new JsonSerializerOptions(JsonSerializerDefaults.Web));
responseBody.Should().BeJson("""{ "id": 1, "tags": ["a"] }""");
```

JSON is stored indented by two spaces, properties in the order they were written, numbers as written and non-ASCII
text unescaped. It is compared as a tree:
- **Maps** compare by key; order does not matter unless you ask for it.
- **Numbers** compare by value: `1`, `1.0` and `10e-1` are equal, and integers beyond 2^53 still compare exactly.
- **Arrays** keep their order. Items are aligned by their longest common subsequence, so inserting one item reports
  that item, not everything after it, and a changed field inside an item is reported by its path:

```text
$[0]                     unexpected in actual
$[1].v (actual $[2].v)   expected "b"   actual "B"   (verified.json:1:31)
```

A property that appears twice in one object is an error, and so is invalid JSON.

## Options

```csharp
var diff = new TreeDiffOptions
{
	MapOrder = MapOrder.Significant,                      
	StrictNumbers = true,                                 
	NullEqualsMissing = true,                              // "x": null equals no "x"
	IgnorePaths = ["$.meta.generatedAt", "$..id", "$.items[*].etag"],
};
json.Should().MatchJsonSnapshot(diff);
```

See [paths and options](https://docs-v3-preview.elastic.dev/reference/options).
The overload that takes `JsonSerializerOptions` serializes with reflection and is marked as such; use the
`JsonTypeInfo<T>` overload with a source-generated context in trimmed or native AOT test projects.
For a short value there is `MatchInlineJsonSnapshot`, which keeps the expected value in the test as a literal: see [inline snapshots](https://docs-v3-preview.elastic.dev/formats/inline).