diff --git a/.github/workflows/alloc-profile.yml b/.github/workflows/alloc-profile.yml
new file mode 100644
index 0000000..b7690a2
--- /dev/null
+++ b/.github/workflows/alloc-profile.yml
@@ -0,0 +1,57 @@
+name: Alloc Profile
+on:
+  push:
+    tags: ['v*']
+  pull_request:
+    paths:
+      - 'benchmark/alloc_profile.jl'
+      - 'benchmark/problem_utils.jl'
+      - 'benchmark/Project.toml'
+      - '.github/workflows/alloc-profile.yml'
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
+
+jobs:
+  alloc-profile:
+    name: Alloc profile (Ipopt + MadNLP)
+    runs-on: ubuntu-latest
+    # Profile.Allocs has high per-allocation overhead that doesn't scale down
+    # with sample_rate — each Ipopt/MadNLP solve under sampling takes ~30-40
+    # min on GH Actions runners even at max_iter=30. Two solves + startup =
+    # ~75 min observed in practice; 90 min gives a comfortable cushion.
+    timeout-minutes: 90
+    permissions:
+      actions: write
+      contents: read
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: julia-actions/setup-julia@v2
+        with:
+          version: '1.11'
+          arch: x64
+
+      - uses: julia-actions/cache@v2
+
+      - name: Instantiate benchmark environment
+        run: julia --project=benchmark -e 'using Pkg; Pkg.instantiate()'
+
+      - name: Run alloc profile
+        env:
+          BENCHMARK_RUNNER: github-actions
+        run: |
+          julia --project=benchmark -t auto -e '
+            using TestItemRunner
+            TestItemRunner.run_tests("benchmark/"; filter = ti -> occursin("alloc_profile", ti.filename))
+          '
+
+      - name: Upload alloc-profile artifacts
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: alloc-profile-${{ github.event.pull_request.number || github.ref_name }}-${{ github.sha }}
+          path: benchmark/results/allocs/
+          retention-days: 90
diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 803ae0a..529fd5e 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -34,13 +34,16 @@ jobs:
       - name: Instantiate benchmark environment
         run: julia --project=benchmark -e 'using Pkg; Pkg.instantiate()'
 
-      - name: Run benchmarks
+      - name: Run benchmarks (excluding alloc profile)
         env:
           BENCHMARK_RUNNER: github-actions
         run: |
           julia --project=benchmark -t auto -e '
             using TestItemRunner
-            TestItemRunner.run_tests("benchmark/")
+            # Alloc profile testitem runs in `.github/workflows/alloc-profile.yml`
+            # because Profile.Allocs adds ~30-40min per solve regardless of
+            # max_iter, making it impractical to gate every PR on it.
+            TestItemRunner.run_tests("benchmark/"; filter = ti -> !occursin("alloc_profile", ti.filename))
           '
 
       - name: Upload benchmark artifacts
diff --git a/benchmark/Project.toml b/benchmark/Project.toml
index 2255f41..f65629f 100644
--- a/benchmark/Project.toml
+++ b/benchmark/Project.toml
@@ -20,4 +20,8 @@ DirectTrajOpt = {path = ".."}
 # results are reproducible. Bump this SHA (and the local Manifest) when HBJ
 # ships a new feature we want to use. Drop in favor of [compat] once HBJ
 # registers in General.
-HarmoniqsBenchmarks = {url = "https://github.com/harmoniqs/HarmoniqsBenchmarks.jl", rev = "5401542c477c0f2da6d66028c513e8a278f4875f"}
+#
+# Bumped from 5401542c (v0.2.0 prep) to c38418cb (post-#12) to pick up the
+# alloc profile analyzer (`top_alloc_types`, `report_alloc_profile`, …)
+# used by `benchmark/alloc_profile.jl`.
+HarmoniqsBenchmarks = {url = "https://github.com/harmoniqs/HarmoniqsBenchmarks.jl", rev = "c38418cb7f932f2ff9a9c6c6eacf9a11ff1018c1"}
diff --git a/benchmark/alloc_profile.jl b/benchmark/alloc_profile.jl
new file mode 100644
index 0000000..812521a
--- /dev/null
+++ b/benchmark/alloc_profile.jl
@@ -0,0 +1,89 @@
+using TestItems
+
+@testitem "Alloc profile: bilinear N=51 (Ipopt + MadNLP)" begin
+    using HarmoniqsBenchmarks, DirectTrajOpt, NamedTrajectories
+    using SparseArrays, ExponentialAction, Random, Dates
+    import MadNLP
+
+    include("$(joinpath(@__DIR__, "problem_utils.jl"))")
+
+    runner = get(ENV, "BENCHMARK_RUNNER", "local")
+
+    # `Profile.Allocs` slows the solve dramatically — `sample_rate = 1.0` is
+    # intractable for a full Ipopt/MadNLP run (>15 min on N=10 in early
+    # experiments), and even `0.01` runs MadNLP at ~3000× slowdown vs the
+    # un-profiled solve. `0.01` keeps the trace tractable while still giving
+    # statistically useful per-frame breakdowns; combined with `max_iter = 30`
+    # (representative per-iter allocation pattern — convergence isn't the
+    # goal) the testitem completes well inside the workflow timeout. The
+    # `1 / sample_rate` scaling applied by `report_alloc_profile` extrapolates
+    # back to total bytes.
+    sample_rate = 0.01
+
+    # JIT warmup so first-call compile of Ipopt/MadNLP extensions, KKT/AD
+    # codegen, and the Profile.Allocs machinery itself doesn't dominate the
+    # sampled trace. Discard the warmup results.
+    let warmup_prob = make_bilinear_problem(; N = 11, seed = 0)
+        DirectTrajOpt.solve!(
+            warmup_prob;
+            options = IpoptOptions(max_iter = 2, print_level = 0),
+        )
+    end
+    let warmup_prob = make_bilinear_problem(; N = 11, seed = 0)
+        DirectTrajOpt.solve!(
+            warmup_prob;
+            options = MadNLPOptions(max_iter = 2, print_level = 6),
+        )
+    end
+
+    results_dir = joinpath(@__DIR__, "results", "allocs")
+    pdims = problem_dims(make_bilinear_problem(; N = 51, seed = 42))
+
+    # Ipopt
+    let prob = make_bilinear_problem(; N = 51, seed = 42)
+        profile = benchmark_memory!(
+            () -> DirectTrajOpt.solve!(
+                prob;
+                options = IpoptOptions(max_iter = 30, print_level = 0),
+            );
+            package = "DirectTrajOpt",
+            solver = "Ipopt",
+            benchmark_name = "alloc_bilinear_N51_ipopt",
+            N = 51,
+            state_dim = pdims.state_dim,
+            control_dim = pdims.control_dim,
+            sample_rate = sample_rate,
+            warmup = false,  # we did our own warmup above
+            runner = runner,
+        )
+        path = save_alloc_profile(results_dir, profile.benchmark_name, profile)
+        println("\n=== Alloc profile: Ipopt (bilinear N=51, sample_rate=$sample_rate) ===")
+        println("  samples=$(profile.total_count)  total≈$(profile.total_bytes) B")
+        println("  saved $path")
+        report_alloc_profile(profile; k_types = 10, k_leaves = 15, k_frames = 15)
+    end
+
+    # MadNLP
+    let prob = make_bilinear_problem(; N = 51, seed = 42)
+        profile = benchmark_memory!(
+            () -> DirectTrajOpt.solve!(
+                prob;
+                options = MadNLPOptions(max_iter = 30, print_level = 6),
+            );
+            package = "DirectTrajOpt",
+            solver = "MadNLP",
+            benchmark_name = "alloc_bilinear_N51_madnlp",
+            N = 51,
+            state_dim = pdims.state_dim,
+            control_dim = pdims.control_dim,
+            sample_rate = sample_rate,
+            warmup = false,
+            runner = runner,
+        )
+        path = save_alloc_profile(results_dir, profile.benchmark_name, profile)
+        println("\n=== Alloc profile: MadNLP (bilinear N=51, sample_rate=$sample_rate) ===")
+        println("  samples=$(profile.total_count)  total≈$(profile.total_bytes) B")
+        println("  saved $path")
+        report_alloc_profile(profile; k_types = 10, k_leaves = 15, k_frames = 15)
+    end
+end