diff --git a/simulations/mixnet/chat-ui/README-fleet.md b/simulations/mixnet/chat-ui/README-fleet.md
new file mode 100644
index 000000000..09c948ded
--- /dev/null
+++ b/simulations/mixnet/chat-ui/README-fleet.md
@@ -0,0 +1,117 @@
+# E2E: logos-chat-ui over the live testnet-0.2 mix fleet
+
+Run `logos-chat-ui` clients against the **deployed testnet-0.2 mix fleet** (5 remote
+mix nodes) instead of the local sim. The client **discovers** the fleet's mix nodes
+(and their curve25519 pubkeys) via libp2p Kademlia service discovery — no node
+addresses or pubkeys are hardcoded.
+
+This is the fleet counterpart of [README.md](README.md) (the local 5-node sim). Key
+differences:
+
+- No local mix nodes to build or run — you dial the live fleet.
+- Credentials come from a **secret bundle** provided by the fleet operator (not
+  `build_setup.sh`).
+- The client picks its RLN membership from an **in-app startup popup** (demo user
+  1–10), and its libp2p peer-ID is **decoupled** from that membership.
+
+---
+
+## 0. Prerequisites
+
+- **Nix** with flakes enabled — the whole client chain is pulled from GitHub via
+  `nix run`; nothing to clone or build by hand.
+- Network access to the fleet (`*.ih-eu-mda1.misc.vaclab.status.im`).
+- macOS or Linux.
+
+## 1. Get the credentials bundle 🔒
+
+The fleet uses **static RLN membership**. Obtain the credentials bundle from the
+fleet operator — a tarball containing:
+
+- `users/user1..user10/` — 10 demo-user RLN keystores,
+- `rln_tree.db` — the shared 15-member tree (5 fleet nodes + 10 demo users),
+- `fleet_bootstrap.txt` — the 5 fleet bootstrap multiaddrs.
+
+> ⚠️ **The bundle is secret — never commit it.** It holds per-user RLN keystores and
+> the shared tree, which together expose the fleet's entire RLN identity. Keep it
+> outside any git repo.
+
+Extract it somewhere local:
+
+```bash
+mkdir -p ~/fleet-creds && tar -xzf chat-app-credentials.tar.gz -C ~/fleet-creds
+export CHAT_CREDS_DIR=~/fleet-creds/chat-app-credentials
+```
+
+## 2. Run a client
+
+```bash
+export CHAT_CREDS_DIR=~/fleet-creds/chat-app-credentials   # from step 1
+export CHAT_CLUSTER_ID=2
+export CHAT_SHARD_ID=0
+export CHAT_MIN_MIX_POOL=4
+export CHAT_MIX_REQUIRED=1
+export CHAT_PORT=0                                          # 0 = random (use distinct ports per client)
+# Receive path: filter-subscribe to one fleet node (any line from the bundle).
+export CHAT_STATIC_PEER="$(grep -m1 '^/dns4' "$CHAT_CREDS_DIR/fleet_bootstrap.txt")"
+
+nix run 'github:logos-co/logos-chat-ui?ref=feat/logos-testnetv02-mix' --accept-flake-config
+```
+
+The first run builds the whole chat chain from GitHub (slow once, cached after). The
+flake locks already pin the matching `logos-chat-module` / `logos-chat` revs — no
+overrides needed.
+
+## 3. Pick a membership in the startup popup
+
+On launch a popup asks which **demo user (1–10)** to use. Each maps to one RLN
+membership in the shared tree. Pick one and hit **Start**:
+
+- The app stages that user's keystore + the shared tree into its run dir, then
+  mounts the mix protocol.
+- It **discovers** the 5 fleet mix nodes via kad (seeded from `fleet_bootstrap.txt`)
+  — watch the bottom status bar fill to **`MIX 4/4`** (`mixReady`).
+- The node comes up immediately ("Connected"); mix discovery fills the pool in the
+  background — the send button enables once the pool reaches the minimum.
+
+**Multiple testers / clients:** each picks a demo-user index. The peer-ID is
+**decoupled** from the membership (random nodekey per run), so two clients can pick
+the *same* index without a peer-ID collision. Use distinct `CHAT_PORT`s.
+
+## 4. Exchange messages
+
+1. In **Client A**: **My Bundle** → copy the intro bundle.
+2. In **Client B**: **+ new** → paste A's bundle + a first message → create.
+3. Send each way — messages route A↔B through the fleet mixnet.
+
+> ⚠️ **Known limitation (2026-06): 2-way messaging over the fleet is not delivering
+> yet.** Sends enter the mix but no SURB reply returns (the recipient receives
+> nothing). The client side is verified correct — discovery, RLN proof, and
+> credential handling all check out, and the client uses the bundle's `rln_tree.db`
+> which matches the tree deployed on the fleet. The issue is under investigation on
+> the **fleet routing** side. **Discovery + startup are fully testable today;
+> message delivery is not.**
+
+## Config reference
+
+| env | meaning |
+|-----|---------|
+| `CHAT_CREDS_DIR` | path to the extracted secret bundle (keystores + `rln_tree.db` + `fleet_bootstrap.txt`) |
+| `CHAT_STATIC_PEER` | a fleet node multiaddr to filter-subscribe to (receive path) |
+| `CHAT_CLUSTER_ID` / `CHAT_SHARD_ID` | `2` / `0` (must match the fleet) |
+| `CHAT_MIN_MIX_POOL` | min mix peers before send is allowed (default `4`) |
+| `CHAT_MIX_REQUIRED` | `1` = force Required (mix-only) mode |
+| `CHAT_PORT` | libp2p port (`0` = random; use distinct ports per client) |
+
+The demo-user index, fleet bootstrap list (`CHAT_KAD_BOOTSTRAP`), and the RLN
+keystore are all derived from the bundle + the popup selection at startup — you don't
+set them by hand.
+
+## How it differs from the sim runbook
+
+| | local sim ([README.md](README.md)) | live fleet (this doc) |
+|--|--|--|
+| mix nodes | 5 local — you build + run them | 5 remote — already deployed |
+| node addresses / pubkeys | hardcoded in `CHAT_MIX_NODES` | **discovered via kad** (`fleet_bootstrap.txt`) |
+| credentials | generated by `build_setup.sh` | **secret bundle** from the fleet operator |
+| membership selection | fixed `CHAT_NODEKEY` | **in-app popup** (demo user 1–10), peer-ID decoupled |
diff --git a/simulations/mixnet/chat-ui/README.md b/simulations/mixnet/chat-ui/README.md
index d7310ba8b..37132ef65 100644
--- a/simulations/mixnet/chat-ui/README.md
+++ b/simulations/mixnet/chat-ui/README.md
@@ -5,6 +5,9 @@ Run two `logos-chat-ui` clients that exchange end-to-end messages **through the
 
 This is a full from-scratch runbook: clone → build → provision → run → message.
 
+> Running against the **live testnet-0.2 mix fleet** instead of a local sim?
+> See [README-fleet.md](README-fleet.md).
+
 The two clients adopt the **two provisioned chat memberships** the sim generates
 (peer-IDs `…1Qx…` and `…RABscN`), via `CHAT_NODEKEY`. RLN keystores are
 peer-ID-derived, so fixing the nodekey makes the right `rln_keystore_<peerId>.json`