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scenarios Parsing Large JSON Response with HttpClient in .NET 5 - OutOfMemoryException

๐Ÿ‘€ Views: 171 ๐Ÿ’ฌ Answers: 1 ๐Ÿ“… Created: 2025-06-24
json httpclient dotnet serialization csharp

I'm having a hard time understanding I'm having trouble with I'm working with an `OutOfMemoryException` when trying to deserialize a large JSON response from an API using `HttpClient` in .NET 5... The JSON data can sometimes exceed 50 MB, and although I've tried using `JsonSerializer.DeserializeAsync` with a stream, the question continues. Hereโ€™s a simplified version of what my code looks like: ```csharp using System.Net.Http; using System.Text.Json; public async Task<MyObject> GetLargeJsonAsync(string url) { using var httpClient = new HttpClient(); using var response = await httpClient.GetAsync(url); response.EnsureSuccessStatusCode(); await using var stream = await response.Content.ReadAsStreamAsync(); var options = new JsonSerializerOptions { PropertyNameCaseInsensitive = true }; return await JsonSerializer.DeserializeAsync<MyObject>(stream, options); } ``` Iโ€™ve also tried increasing the memory limit for the app in the `appsettings.json` by setting the `gcServer` option to `true`, but that didnโ€™t help either. The behavior I get is: ``` System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown. ``` Additionally, Iโ€™ve looked into using `JsonDocument` for a forward-only parsing approach, but it seems like it would still hit the memory ceiling when the JSON is too large. Is there a recommended strategy or best practice for handling large JSON responses in .NET 5 to avoid this scenario? Any insights on performance or design patterns for streaming deserialization would be greatly appreciated! This is happening in both development and production on Linux. I'm open to any suggestions. Any feedback is welcome!