diff --git a/ShoppingAssistantApi.Api/Controllers/WeatherForecastController.cs b/ShoppingAssistantApi.Api/Controllers/WeatherForecastController.cs
deleted file mode 100644
index 86d61b0..0000000
--- a/ShoppingAssistantApi.Api/Controllers/WeatherForecastController.cs
+++ /dev/null
@@ -1,31 +0,0 @@
-using Microsoft.AspNetCore.Mvc;
-
-namespace ShoppingAssistantApi.Api.Controllers;
-[ApiController]
-[Route("[controller]")]
-public class WeatherForecastController : ControllerBase
-{
-    private static readonly string[] Summaries = new[]
-    {
-        "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
-    };
-
-    private readonly ILogger<WeatherForecastController> _logger;
-
-    public WeatherForecastController(ILogger<WeatherForecastController> logger)
-    {
-        _logger = logger;
-    }
-
-    [HttpGet(Name = "GetWeatherForecast")]
-    public IEnumerable<WeatherForecast> Get()
-    {
-        return Enumerable.Range(1, 5).Select(index => new WeatherForecast
-        {
-            Date = DateOnly.FromDateTime(DateTime.Now.AddDays(index)),
-            TemperatureC = Random.Shared.Next(-20, 55),
-            Summary = Summaries[Random.Shared.Next(Summaries.Length)]
-        })
-        .ToArray();
-    }
-}
diff --git a/ShoppingAssistantApi.Api/Program.cs b/ShoppingAssistantApi.Api/Program.cs
index 4a1e95b..e7f574b 100644
--- a/ShoppingAssistantApi.Api/Program.cs
+++ b/ShoppingAssistantApi.Api/Program.cs
@@ -12,6 +12,7 @@ builder.Services.AddJWTTokenAuthentication(builder.Configuration);
 builder.Services.AddMapper();
 builder.Services.AddInfrastructure();
 builder.Services.AddServices();
+builder.Services.AddHttpClient(builder.Configuration);
 builder.Services.AddGraphQl();
 builder.Services.AddControllers();
 
diff --git a/ShoppingAssistantApi.Api/ShoppingAssistantApi.Api.csproj b/ShoppingAssistantApi.Api/ShoppingAssistantApi.Api.csproj
index 33cec29..50dd57a 100644
--- a/ShoppingAssistantApi.Api/ShoppingAssistantApi.Api.csproj
+++ b/ShoppingAssistantApi.Api/ShoppingAssistantApi.Api.csproj
@@ -21,4 +21,8 @@
     <ProjectReference Include="..\ShoppingAssistantApi.Persistance\ShoppingAssistantApi.Persistance.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Folder Include="Controllers\" />
+  </ItemGroup>
+
 </Project>
diff --git a/ShoppingAssistantApi.Api/WeatherForecast.cs b/ShoppingAssistantApi.Api/WeatherForecast.cs
deleted file mode 100644
index 360f533..0000000
--- a/ShoppingAssistantApi.Api/WeatherForecast.cs
+++ /dev/null
@@ -1,12 +0,0 @@
-namespace ShoppingAssistantApi.Api;
-
-public class WeatherForecast
-{
-    public DateOnly Date { get; set; }
-
-    public int TemperatureC { get; set; }
-
-    public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
-
-    public string? Summary { get; set; }
-}
diff --git a/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiChoice.cs b/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiChoice.cs
new file mode 100644
index 0000000..3ce06dc
--- /dev/null
+++ b/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiChoice.cs
@@ -0,0 +1,12 @@
+namespace ShoppingAssistantApi.Application.Models.OpenAi;
+
+public class OpenAiChoice
+{
+    public OpenAiMessage Message { get; set; }
+    
+    public OpenAiDelta Delta { get; set; }
+
+    public string FinishReason { get; set; }
+    
+    public int Index { get; set; }
+}
\ No newline at end of file
diff --git a/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiDelta.cs b/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiDelta.cs
new file mode 100644
index 0000000..c9b7dbc
--- /dev/null
+++ b/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiDelta.cs
@@ -0,0 +1,8 @@
+namespace ShoppingAssistantApi.Application.Models.OpenAi;
+
+public class OpenAiDelta
+{
+    public string Role { get; set; }
+
+    public string Content { get; set; }
+}
\ No newline at end of file
diff --git a/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiMessage.cs b/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiMessage.cs
index 91bd757..edb4cba 100644
--- a/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiMessage.cs
+++ b/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiMessage.cs
@@ -4,7 +4,7 @@ namespace ShoppingAssistantApi.Application.Models.OpenAi;
 
 public class OpenAiMessage
 {
-    public OpenAiRole Role { get; set; }
+    public string Role { get; set; }
 
     public string Content { get; set; }
 }
diff --git a/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiResponse.cs b/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiResponse.cs
new file mode 100644
index 0000000..991b854
--- /dev/null
+++ b/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiResponse.cs
@@ -0,0 +1,16 @@
+namespace ShoppingAssistantApi.Application.Models.OpenAi;
+
+public class OpenAiResponse
+{
+    public string Id { get; set; }
+
+    public string Object { get; set; }
+
+    public int Created { get; set; }
+
+    public string Model { get; set; }
+
+    public OpenAiUsage Usage { get; set; }
+
+    public List<OpenAiChoice> Choices { get; set; }
+}
\ No newline at end of file
diff --git a/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiUsage.cs b/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiUsage.cs
new file mode 100644
index 0000000..6789eac
--- /dev/null
+++ b/ShoppingAssistantApi.Application/Models/OpenAi/OpenAiUsage.cs
@@ -0,0 +1,10 @@
+namespace ShoppingAssistantApi.Application.Models.OpenAi;
+
+public class OpenAiUsage
+{
+    public int PromptTokens { get; set; }
+
+    public int CompletionTokens { get; set; }
+
+    public int TotalTokens { get; set; }
+}
\ No newline at end of file
diff --git a/ShoppingAssistantApi.Domain/Enums/OpenAiRole.cs b/ShoppingAssistantApi.Domain/Enums/OpenAiRole.cs
index 54d2c0a..a01e6a5 100644
--- a/ShoppingAssistantApi.Domain/Enums/OpenAiRole.cs
+++ b/ShoppingAssistantApi.Domain/Enums/OpenAiRole.cs
@@ -6,3 +6,21 @@ public enum OpenAiRole
     User,
     Assistant
 }
+
+public static class OpenAiRoleExtensions
+{
+    public static string RequestConvert(this OpenAiRole role)
+    {
+        switch (role)
+        {
+            case OpenAiRole.System:
+                return "system";
+            case OpenAiRole.Assistant:
+                return "assistant";
+            case OpenAiRole.User:
+                return "user";
+            default:
+                return "";
+        }
+    }
+}
\ No newline at end of file
diff --git a/ShoppingAssistantApi.Infrastructure/InfrastructureExtentions/ServicesExtention.cs b/ShoppingAssistantApi.Infrastructure/InfrastructureExtentions/ServicesExtention.cs
index 0db9d03..cbc7b65 100644
--- a/ShoppingAssistantApi.Infrastructure/InfrastructureExtentions/ServicesExtention.cs
+++ b/ShoppingAssistantApi.Infrastructure/InfrastructureExtentions/ServicesExtention.cs
@@ -1,8 +1,10 @@
-using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
 using ShoppingAssistantApi.Application.IServices;
 using ShoppingAssistantApi.Application.IServices.Identity;
 using ShoppingAssistantApi.Infrastructure.Services;
 using ShoppingAssistantApi.Infrastructure.Services.Identity;
+using System.Net.Http.Headers;
 
 namespace ShoppingAssistantApi.Infrastructure.InfrastructureExtentions;
 public static class ServicesExtention
@@ -15,6 +17,21 @@ public static class ServicesExtention
         services.AddScoped<ITokensService, TokensService>();
         services.AddScoped<IUsersService, UsersService>();
         services.AddScoped<IWishlistsService, WishlistsService>();
+        services.AddScoped<IOpenAiService, OpenAiService>();
+
+        return services;
+    }
+
+    public static IServiceCollection AddHttpClient(this IServiceCollection services, IConfiguration configuration)
+    {
+        services.AddHttpClient(
+            "OpenAiHttpClient",
+            client =>
+            {
+                client.BaseAddress = new Uri(configuration.GetValue<string>("ApiUri"));
+                client.DefaultRequestHeaders.Authorization = 
+                    new AuthenticationHeaderValue("Bearer", configuration.GetValue<string>("ApiKey"));
+            });
 
         return services;
     }
diff --git a/ShoppingAssistantApi.Infrastructure/Services/OpenAiService.cs b/ShoppingAssistantApi.Infrastructure/Services/OpenAiService.cs
index 9ed750a..233388c 100644
--- a/ShoppingAssistantApi.Infrastructure/Services/OpenAiService.cs
+++ b/ShoppingAssistantApi.Infrastructure/Services/OpenAiService.cs
@@ -1,3 +1,9 @@
+using System.IO;
+using System.Net.Http.Headers;
+using System.Text;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+using Newtonsoft.Json.Serialization;
 using ShoppingAssistantApi.Application.IServices;
 using ShoppingAssistantApi.Application.Models.OpenAi;
 
@@ -5,20 +11,61 @@ namespace ShoppingAssistantApi.Infrastructure.Services;
 
 public class OpenAiService : IOpenAiService
 {
+
+    private readonly JsonSerializerSettings _jsonSettings = new JsonSerializerSettings
+    {
+        ContractResolver = new DefaultContractResolver
+        {
+            NamingStrategy = new SnakeCaseNamingStrategy()
+        },
+        NullValueHandling = NullValueHandling.Ignore,
+    };
+
     private readonly HttpClient _httpClient;
 
-    public OpenAiService(HttpClient client)
+    public OpenAiService(IHttpClientFactory httpClientFactory)
     {
-        _httpClient = client;
+        _httpClient = httpClientFactory.CreateClient("OpenAiHttpClient");
     }
 
-    public Task<OpenAiMessage> GetChatCompletion(ChatCompletionRequest chat, CancellationToken cancellationToken)
+    public async Task<OpenAiMessage> GetChatCompletion(ChatCompletionRequest chat, CancellationToken cancellationToken)
     {
-        throw new NotImplementedException();
+        chat.Stream = false; 
+        var jsonBody = JsonConvert.SerializeObject(chat, _jsonSettings);
+        var body = new StringContent(jsonBody, Encoding.UTF8, "application/json");
+
+        using var httpResponse = await _httpClient.PostAsync("", body, cancellationToken);
+
+        var responseBody = await httpResponse.Content.ReadAsStringAsync(cancellationToken);
+
+        var data = JsonConvert.DeserializeObject<OpenAiResponse>(responseBody);
+
+        return data.Choices[0].Message;
     }
 
-    public IAsyncEnumerable<string> GetChatCompletionStream(ChatCompletionRequest chat, CancellationToken cancellationToken)
+    public async IAsyncEnumerable<string> GetChatCompletionStream(ChatCompletionRequest chat, CancellationToken cancellationToken)
     {
-        throw new NotImplementedException();
+        chat.Stream = true;
+        var jsonBody = JsonConvert.SerializeObject(chat, _jsonSettings);
+        
+        var body = new StringContent(jsonBody, Encoding.UTF8, "application/json");
+
+        using var httpResponse = await _httpClient.PostAsync("", body, cancellationToken);
+
+        using var responseStream = await httpResponse.Content.ReadAsStreamAsync(cancellationToken);
+        using var reader = new StreamReader(responseStream, Encoding.UTF8);
+
+        while (!cancellationToken.IsCancellationRequested)
+        {
+            var jsonChunk = await reader.ReadLineAsync();
+            if (jsonChunk.StartsWith("data: "))
+            {
+                jsonChunk = jsonChunk.Substring("data: ".Length);
+                if (jsonChunk == "[DONE]") break;
+                var data = JsonConvert.DeserializeObject<OpenAiResponse>(jsonChunk);
+                if (data.Choices[0].Delta.Content == "" || data.Choices[0].Delta.Content == null) continue;
+                yield return data.Choices[0].Delta.Content;
+            }
+        }
     }
-}
+}
\ No newline at end of file
diff --git a/ShoppingAssistantApi.Infrastructure/ShoppingAssistantApi.Infrastructure.csproj b/ShoppingAssistantApi.Infrastructure/ShoppingAssistantApi.Infrastructure.csproj
index 6b6f722..ab6f623 100644
--- a/ShoppingAssistantApi.Infrastructure/ShoppingAssistantApi.Infrastructure.csproj
+++ b/ShoppingAssistantApi.Infrastructure/ShoppingAssistantApi.Infrastructure.csproj
@@ -11,6 +11,7 @@
     <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="7.0.0" />
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="7.0.1" />
     <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="6.32.0" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
     <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="6.32.0" />
   </ItemGroup>
 
diff --git a/ShoppingAssistantApi.UnitTests/OpenAiServiceTests.cs b/ShoppingAssistantApi.UnitTests/OpenAiServiceTests.cs
new file mode 100644
index 0000000..d9dffd9
--- /dev/null
+++ b/ShoppingAssistantApi.UnitTests/OpenAiServiceTests.cs
@@ -0,0 +1,155 @@
+using System.Net;
+using Moq;
+using Moq.Protected;
+using ShoppingAssistantApi.Application.IServices;
+using ShoppingAssistantApi.Application.Models.OpenAi;
+using ShoppingAssistantApi.Domain.Enums;
+using ShoppingAssistantApi.Infrastructure.Services;
+
+namespace ShoppingAssistantApi.UnitTests;
+
+public class OpenAiServiceTests
+{
+    private readonly IOpenAiService _openAiService;
+
+    private readonly Mock<HttpMessageHandler> _mockHttpMessageHandler;
+
+    private readonly Mock<IHttpClientFactory> _mockHttpClientFactory;
+
+    public OpenAiServiceTests()
+    {
+        _mockHttpClientFactory = new Mock<IHttpClientFactory>();
+        _mockHttpMessageHandler = new Mock<HttpMessageHandler>();
+
+        var client = new HttpClient(_mockHttpMessageHandler.Object);
+        client.BaseAddress = new Uri("https://www.google.com.ua/");
+
+        _mockHttpClientFactory
+            .Setup(factory => factory.CreateClient(It.IsAny<string>()))
+            .Returns(() =>
+            {
+                return client;
+            });
+        
+        _openAiService = new OpenAiService(_mockHttpClientFactory.Object);
+    }
+
+    [Fact]
+    public async Task GetChatCompletion_ValidChat_ReturnsNewMessage()
+    {
+        // Arrange
+        _mockHttpMessageHandler
+            .Protected()
+            .Setup<Task<HttpResponseMessage>>(
+                "SendAsync",
+                ItExpr.IsAny<HttpRequestMessage>(),
+                ItExpr.IsAny<CancellationToken>()
+            )
+            .ReturnsAsync(new HttpResponseMessage
+            {
+                StatusCode = HttpStatusCode.OK,
+                Content = new StringContent(@"
+                {
+                    ""id"": ""chatcmpl-89OMdgTZXOLAXv7bPUJ4SwrPpS5Md"",
+                    ""object"": ""chat.completion"",
+                    ""created"": 1697249299,
+                    ""model"": ""gpt-3.5-turbo-0613"",
+                    ""choices"": [
+                        {
+                            ""index"": 0,
+                            ""message"": {
+                                ""role"": ""assistant"",
+                                ""content"": ""Hello, World!""
+                            },
+                            ""finish_reason"": ""stop""
+                        }
+                    ],
+                    ""usage"": {
+                        ""prompt_tokens"": 10,
+                        ""completion_tokens"": 3,
+                        ""total_tokens"": 13
+                    }
+                }"),
+            });
+
+        var chat = new ChatCompletionRequest
+        {
+            Messages = new List<OpenAiMessage>
+            {
+                new OpenAiMessage
+                {
+                    Role = OpenAiRole.User.RequestConvert(),
+                    Content = "Return Hello World!"
+                }
+            }
+        };
+
+        // Act
+        var newMessage = await _openAiService.GetChatCompletion(chat, CancellationToken.None);
+
+        // Assert
+        Assert.NotNull(newMessage);
+        Assert.Equal("Hello, World!", newMessage.Content);
+    }
+
+    // TODO: Add more tests
+/*
+    [Fact]
+    public async Task GetChatCompletionStream_ValidChat_ReturnsNewMessage()
+    {
+        // Arrange
+        _mockHttpMessageHandler
+            .Protected()
+            .Setup<Task<HttpResponseMessage>>(
+                "SendAsync",
+                ItExpr.IsAny<HttpRequestMessage>(),
+                ItExpr.IsAny<CancellationToken>()
+            )
+            .ReturnsAsync(new HttpResponseMessage
+            {
+                StatusCode = HttpStatusCode.OK,
+                Content = new StringContent(@"
+                {
+                    ""id"": ""chatcmpl-89OMdgTZXOLAXv7bPUJ4SwrPpS5Md"",
+                    ""object"": ""chat.completion"",
+                    ""created"": 1697249299,
+                    ""model"": ""gpt-3.5-turbo-0613"",
+                    ""choices"": [
+                        {
+                            ""index"": 0,
+                            ""message"": {
+                                ""role"": ""assistant"",
+                                ""content"": ""Hello World!""
+                            },
+                            ""finish_reason"": ""stop""
+                        }
+                    ],
+                    ""usage"": {
+                        ""prompt_tokens"": 10,
+                        ""completion_tokens"": 3,
+                        ""total_tokens"": 13
+                    }
+                }"),
+            });
+
+        var chat = new ChatCompletionRequest
+        {
+            Messages = new List<OpenAiMessage>
+            {
+                new OpenAiMessage
+                {
+                    Role = OpenAiRole.User.RequestConvert(),
+                    Content = "Return Hello World!"
+                }
+            }
+        };
+
+        // Act
+        var newMessage = _openAiService.GetChatCompletionStream(chat, CancellationToken.None);
+
+        // Assert
+        Assert.NotNull(newMessage);
+        Assert.Equal("Hello World!", newMessage.ToString());
+    }
+*/
+}
\ No newline at end of file