diff --git a/Foxnouns.Backend/Controllers/MembersController.cs b/Foxnouns.Backend/Controllers/MembersController.cs
index 46fe51e..59bec37 100644
--- a/Foxnouns.Backend/Controllers/MembersController.cs
+++ b/Foxnouns.Backend/Controllers/MembersController.cs
@@ -9,6 +9,7 @@ using Foxnouns.Backend.Services;
 using Foxnouns.Backend.Utils;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.EntityFrameworkCore;
+using NodaTime;
 
 namespace Foxnouns.Backend.Controllers;
 
@@ -19,7 +20,8 @@ public class MembersController(
     MemberRendererService memberRenderer,
     ISnowflakeGenerator snowflakeGenerator,
     ObjectStorageService objectStorageService,
-    IQueue queue) : ApiControllerBase
+    IQueue queue,
+    IClock clock) : ApiControllerBase
 {
     private readonly ILogger _logger = logger.ForContext<MembersController>();
 
@@ -114,4 +116,25 @@ public class MembersController(
         List<FieldEntry>? Names,
         List<Pronoun>? Pronouns,
         List<Field>? Fields);
+
+    [HttpPost("/api/v2/users/@me/members/{memberRef}/reroll-sid")]
+    [Authorize("member.update")]
+    [ProducesResponseType<UserRendererService.UserResponse>(statusCode: StatusCodes.Status200OK)]
+    public async Task<IActionResult> RerollSidAsync(string memberRef)
+    {
+        var member = await db.ResolveMemberAsync(CurrentUser!.Id, memberRef);
+
+        var minTimeAgo = clock.GetCurrentInstant() - Duration.FromHours(1);
+        if (CurrentUser!.LastSidReroll > minTimeAgo)
+            throw new ApiError.BadRequest("Cannot reroll short ID yet");
+
+        await db.Members.Where(m => m.Id == member.Id)
+            .ExecuteUpdateAsync(s => s
+                .SetProperty(m => m.Sid, _ => db.FindFreeMemberSid()));
+
+        // Re-fetch member so we can be sure the sid is correct
+        var updatedMember = await db.ResolveMemberAsync(CurrentUser!.Id, memberRef);
+
+        return Ok(memberRenderer.RenderMember(updatedMember, CurrentToken));
+    }
 }
\ No newline at end of file
diff --git a/Foxnouns.Backend/Controllers/UsersController.cs b/Foxnouns.Backend/Controllers/UsersController.cs
index bb3417c..7d1177e 100644
--- a/Foxnouns.Backend/Controllers/UsersController.cs
+++ b/Foxnouns.Backend/Controllers/UsersController.cs
@@ -8,6 +8,7 @@ using Foxnouns.Backend.Services;
 using Foxnouns.Backend.Utils;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.EntityFrameworkCore;
+using NodaTime;
 
 namespace Foxnouns.Backend.Controllers;
 
@@ -16,7 +17,8 @@ public class UsersController(
     DatabaseContext db,
     UserRendererService userRenderer,
     ISnowflakeGenerator snowflakeGenerator,
-    IQueue queue) : ApiControllerBase
+    IQueue queue,
+    IClock clock) : ApiControllerBase
 {
     [HttpGet("{userRef}")]
     [ProducesResponseType<UserRendererService.UserResponse>(statusCode: StatusCodes.Status200OK)]
@@ -213,4 +215,22 @@ public class UsersController(
     {
         public bool? DarkMode { get; init; }
     }
+
+    [HttpPost("@me/reroll-sid")]
+    [Authorize("user.update")]
+    [ProducesResponseType<UserRendererService.UserResponse>(statusCode: StatusCodes.Status200OK)]
+    public async Task<IActionResult> RerollSidAsync()
+    {
+        var minTimeAgo = clock.GetCurrentInstant() - Duration.FromHours(1);
+        if (CurrentUser!.LastSidReroll > minTimeAgo)
+            throw new ApiError.BadRequest("Cannot reroll short ID yet");
+
+        await db.Users.Where(u => u.Id == CurrentUser.Id)
+            .ExecuteUpdateAsync(s => s
+                .SetProperty(u => u.Sid, _ => db.FindFreeUserSid())
+                .SetProperty(u => u.LastSidReroll, _ => clock.GetCurrentInstant()));
+        
+        var user = await db.ResolveUserAsync(CurrentUser.Id);
+        return Ok(await userRenderer.RenderUserAsync(user, CurrentUser, CurrentToken, renderMembers: false));
+    }
 }
\ No newline at end of file
diff --git a/Foxnouns.Backend/Database/DatabaseContext.cs b/Foxnouns.Backend/Database/DatabaseContext.cs
index b46079b..e907abd 100644
--- a/Foxnouns.Backend/Database/DatabaseContext.cs
+++ b/Foxnouns.Backend/Database/DatabaseContext.cs
@@ -76,7 +76,23 @@ public class DatabaseContext : DbContext
         modelBuilder.Entity<Member>().Property(m => m.Fields).HasColumnType("jsonb");
         modelBuilder.Entity<Member>().Property(m => m.Names).HasColumnType("jsonb");
         modelBuilder.Entity<Member>().Property(m => m.Pronouns).HasColumnType("jsonb");
+
+        modelBuilder.HasDbFunction(typeof(DatabaseContext).GetMethod(nameof(FindFreeUserSid))!)
+            .HasName("find_free_user_sid");
+
+        modelBuilder.HasDbFunction(typeof(DatabaseContext).GetMethod(nameof(FindFreeMemberSid))!)
+            .HasName("find_free_member_sid");
     }
+
+    /// <summary>
+    /// Dummy method that calls <c>find_free_user_sid()</c> when used in an EF Core query.
+    /// </summary>
+    public string FindFreeUserSid() => throw new NotSupportedException();
+
+    /// <summary>
+    /// Dummy method that calls <c>find_free_member_sid()</c> when used in an EF Core query.
+    /// </summary>
+    public string FindFreeMemberSid() => throw new NotSupportedException();
 }
 
 [SuppressMessage("ReSharper", "UnusedType.Global", Justification = "Used by EF Core's migration generator")]