diff --git a/Api/Api.csproj b/Api/Api.csproj
index bc5025d..4edeb20 100644
--- a/Api/Api.csproj
+++ b/Api/Api.csproj
@@ -24,7 +24,9 @@
     </ItemGroup>
 
     <ItemGroup>
+      <PackageReference Include="FirebaseAdmin" Version="2.4.0" />
       <PackageReference Include="Grpc.AspNetCore" Version="2.60.0" />
+      <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="8.0.1" />
       <PackageReference Include="Microsoft.AspNetCore.Grpc.JsonTranscoding" Version="8.0.1" />
       <PackageReference Include="Microsoft.AspNetCore.Grpc.Swagger" Version="0.8.1" />
       <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="8.0.1">
@@ -37,6 +39,7 @@
       <PackageReference Include="OpenTelemetry.Exporter.Console" Version="1.7.0" />
       <PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.7.0" />
       <PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.7.0" />
+      <PackageReference Include="OpenTelemetry.Instrumentation.Http" Version="1.7.0" />
     </ItemGroup>
 
 </Project>
diff --git a/Api/Authorization/AuthorizeMembersAttribute.cs b/Api/Authorization/AuthorizeMembersAttribute.cs
new file mode 100644
index 0000000..8fbd4a7
--- /dev/null
+++ b/Api/Authorization/AuthorizeMembersAttribute.cs
@@ -0,0 +1,12 @@
+using Api.Entities;
+using Microsoft.AspNetCore.Authorization;
+
+namespace Api.Authorization;
+
+public class AuthorizeMembersAttribute: AuthorizeAttribute
+{
+    public AuthorizeMembersAttribute(params UserMemberType[] memberTypes)
+    {
+        Roles = string.Join(",", memberTypes);
+    }
+}
\ No newline at end of file
diff --git a/Api/Authorization/ClaimsTransformation.cs b/Api/Authorization/ClaimsTransformation.cs
new file mode 100644
index 0000000..803b62b
--- /dev/null
+++ b/Api/Authorization/ClaimsTransformation.cs
@@ -0,0 +1,31 @@
+using System.Security.Claims;
+using Api.Context;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.EntityFrameworkCore;
+
+namespace Api.Authorization;
+
+public class ClaimsTransformation(AppDbContext dbContext): IClaimsTransformation
+{
+    public async Task<ClaimsPrincipal> TransformAsync(ClaimsPrincipal principal)
+    {
+        var sub = principal.Claims.SingleOrDefault(c => c.Type == "user_id");
+        if (sub is null)
+        {
+            return principal;
+        }
+
+        var user = await dbContext.Users.SingleOrDefaultAsync(u => u.FirebaseId == sub.Value);
+        if (user is null)
+        {
+            return principal;
+        }
+
+        var ci = new ClaimsIdentity();
+        ci.AddClaim(new Claim(ClaimTypes.Role, user.MemberType.ToString()));
+        
+        principal.AddIdentity(ci);
+
+        return principal;
+    }
+}
\ No newline at end of file
diff --git a/Api/Program.cs b/Api/Program.cs
index 16a674a..82ca29c 100644
--- a/Api/Program.cs
+++ b/Api/Program.cs
@@ -1,6 +1,10 @@
+using Api.Authorization;
 using Api.Context;
 using Api.Services.V1;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.AspNetCore.Authentication.JwtBearer;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.IdentityModel.Tokens;
 using Microsoft.OpenApi.Models;
 using Npgsql;
 using OpenTelemetry.Trace;
@@ -9,10 +13,27 @@
 
 builder.Services.AddOpenTelemetry()
     .WithTracing(tracerProviderBuilder => tracerProviderBuilder
-        .AddAspNetCoreInstrumentation()
         .AddNpgsql()
+        .AddHttpClientInstrumentation()
+        .AddAspNetCoreInstrumentation()
         .AddConsoleExporter());
 
+builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
+    .AddJwtBearer(options =>
+    {
+        var projectId = builder.Configuration.GetValue<string>("Firebase:ProjectId");
+        options.Authority = $"https://securetoken.google.com/{projectId}";
+        options.TokenValidationParameters = new TokenValidationParameters
+        {
+            ValidIssuer = $"https://securetoken.google.com/{projectId}",
+            ValidAudience = projectId,
+            ValidateIssuerSigningKey = true,
+            ValidateTokenReplay = true
+        };
+    });
+
+builder.Services.AddAuthorization();
+
 builder.Services
     .AddGrpc()
     .AddJsonTranscoding();
@@ -21,6 +42,33 @@
 {
     c.SwaggerDoc("v1", new OpenApiInfo { Title = "SST Alumni Association API", Version = "v1" });
 
+    c.AddSecurityDefinition("Bearer", new OpenApiSecurityScheme
+    {
+        In = ParameterLocation.Header,
+        Description = "Firebase ID Token",
+        Name = "Authorization",
+        Type = SecuritySchemeType.Http,
+        BearerFormat = "JWT",
+        Scheme = JwtBearerDefaults.AuthenticationScheme
+    });
+
+    c.AddSecurityRequirement(
+        new OpenApiSecurityRequirement
+        {
+            {
+                new OpenApiSecurityScheme
+                {
+                    Reference = new OpenApiReference
+                    {
+                        Type = ReferenceType.SecurityScheme,
+                        Id = "Bearer"
+                    }
+                },
+                Array.Empty<string>()
+            }
+        }
+    );
+
     var filePath = Path.Combine(AppContext.BaseDirectory, "Api.xml");
     c.IncludeXmlComments(filePath);
     c.IncludeGrpcXmlComments(filePath, includeControllerXmlComments: true);
@@ -32,6 +80,8 @@
     builder.Configuration.GetConnectionString("Postgres")
 );
 
+builder.Services.AddTransient<IClaimsTransformation, ClaimsTransformation>();
+
 var app = builder.Build();
 
 using (var scope = app.Services.CreateScope())
@@ -40,6 +90,9 @@
     await db.Database.MigrateAsync();
 }
 
+app.UseAuthentication();
+app.UseAuthorization();
+
 app.MapGrpcService<ArticleServiceV1>();
 app.MapGrpcService<UserServiceV1>();
 app.MapGrpcService<EventServiceV1>();
diff --git a/Api/Services/V1/UserService.cs b/Api/Services/V1/UserService.cs
index 9d26e50..94609a8 100644
--- a/Api/Services/V1/UserService.cs
+++ b/Api/Services/V1/UserService.cs
@@ -1,15 +1,20 @@
+using Api.Authorization;
 using Api.Context;
 using Api.Extensions;
 using Google.Protobuf.WellKnownTypes;
 using Grpc.Core;
+using Microsoft.AspNetCore.Authorization;
 using Microsoft.EntityFrameworkCore;
 using User.V1;
+using Enum = System.Enum;
+using UserMemberType = Api.Entities.UserMemberType;
 
 namespace Api.Services.V1;
 
 /// <inheritdoc />
 public class UserServiceV1(ILogger<UserServiceV1> logger, AppDbContext dbContext) : UserService.UserServiceBase
 {
+    [AuthorizeMembers(UserMemberType.Exco)]
     public override async Task<ListUsersResponse> ListUsers(ListUsersRequest request, ServerCallContext context)
     {
         return new ListUsersResponse
diff --git a/Api/appsettings.json b/Api/appsettings.json
index 10f68b8..dec13cb 100644
--- a/Api/appsettings.json
+++ b/Api/appsettings.json
@@ -5,5 +5,8 @@
       "Microsoft.AspNetCore": "Warning"
     }
   },
-  "AllowedHosts": "*"
+  "AllowedHosts": "*",
+  "Firebase": {
+    "ProjectId": "sstaa-app"
+  }
 }