diff --git a/website/docs/developer-guide/architecture.md b/website/docs/developer-guide/architecture.md
index 88ad962699..d44dc1d532 100644
--- a/website/docs/developer-guide/architecture.md
+++ b/website/docs/developer-guide/architecture.md
@@ -106,7 +106,7 @@ hermes-agent/
 │   ├── credential_files.py   # File-based credential passthrough
 │   ├── env_passthrough.py    # Env var passthrough for sandboxes
 │   ├── ansi_strip.py         # ANSI escape stripping
-│   └── environments/         # Terminal backends (local, docker, ssh, modal, daytona, singularity)
+│   └── environments/         # Terminal backends (local, docker, ssh, modal, daytona, singularity, koyeb)
 │
 ├── gateway/                  # Messaging platform gateway
 │   ├── run.py                # GatewayRunner — message dispatch (~9,000 lines)
diff --git a/website/docs/developer-guide/environments.md b/website/docs/developer-guide/environments.md
index 3409f30473..0ec1968c77 100644
--- a/website/docs/developer-guide/environments.md
+++ b/website/docs/developer-guide/environments.md
@@ -84,7 +84,7 @@ The foundation from `atroposlib`. Provides:
 ### HermesAgentBaseEnv
 
 The hermes-agent layer (`environments/hermes_base_env.py`). Adds:
-- **Terminal backend configuration** — sets `TERMINAL_ENV` for sandboxed execution (local, Docker, Modal, Daytona, SSH, Singularity)
+- **Terminal backend configuration** — sets `TERMINAL_ENV` for sandboxed execution (local, Docker, Modal, Daytona, SSH, Singularity, Koyeb)
 - **Tool resolution** — `_resolve_tools_for_group()` calls hermes-agent's `get_tool_definitions()` to get the right tool schemas based on enabled/disabled toolsets
 - **Agent loop integration** — `collect_trajectory()` runs `HermesAgentLoop` and scores the result
 - **Two-phase operation** — Phase 1 (OpenAI server) for eval/SFT, Phase 2 (VLLM ManagedServer) for full RL with logprobs
@@ -426,7 +426,7 @@ See `environments/benchmarks/yc_bench/yc_bench_env.py` for a clean, well-documen
 | `max_agent_turns` | `int` | `30` | Max LLM calls per rollout |
 | `agent_temperature` | `float` | `1.0` | Sampling temperature |
 | `system_prompt` | `str` | `None` | System message for the agent |
-| `terminal_backend` | `str` | `"local"` | `local`, `docker`, `modal`, `daytona`, `ssh`, `singularity` |
+| `terminal_backend` | `str` | `"local"` | `local`, `docker`, `modal`, `daytona`, `ssh`, `singularity`, `koyeb` |
 | `terminal_timeout` | `int` | `120` | Seconds per terminal command |
 | `terminal_lifetime` | `int` | `3600` | Max sandbox lifetime |
 | `dataset_name` | `str` | `None` | HuggingFace dataset identifier |
diff --git a/website/docs/user-guide/configuration.md b/website/docs/user-guide/configuration.md
index 80f5c6f88b..517c50d645 100644
--- a/website/docs/user-guide/configuration.md
+++ b/website/docs/user-guide/configuration.md
@@ -83,17 +83,18 @@ Leaving these unset keeps the legacy defaults (`HERMES_API_TIMEOUT=1800`s, `HERM
 
 ## Terminal Backend Configuration
 
-Hermes supports six terminal backends. Each determines where the agent's shell commands actually execute — your local machine, a Docker container, a remote server via SSH, a Modal cloud sandbox, a Daytona workspace, or a Singularity/Apptainer container.
+Hermes supports seven terminal backends. Each determines where the agent's shell commands actually execute — your local machine, a Docker container, a remote server via SSH, a Modal cloud sandbox, a Daytona workspace, a Singularity/Apptainer container, or a Koyeb cloud sandbox.
 
 ```yaml
 terminal:
-  backend: local    # local | docker | ssh | modal | daytona | singularity
+  backend: local    # local | docker | ssh | modal | daytona | singularity | koyeb
   cwd: "."          # Working directory ("." = current dir for local, "/root" for containers)
   timeout: 180      # Per-command timeout in seconds
   env_passthrough: []  # Env var names to forward to sandboxed execution (terminal + execute_code)
   singularity_image: "docker://nikolaik/python-nodejs:python3.11-nodejs20"  # Container image for Singularity backend
   modal_image: "nikolaik/python-nodejs:python3.11-nodejs20"                 # Container image for Modal backend
   daytona_image: "nikolaik/python-nodejs:python3.11-nodejs20"               # Container image for Daytona backend
+  koyeb_image: "koyeb/sandbox:latest"                                       # Container image for Koyeb backend
 ```
 
 For cloud sandboxes such as Modal and Daytona, `container_persistent: true` means Hermes will try to preserve filesystem state across sandbox recreation. It does not promise that the same live sandbox, PID space, or background processes will still be running later.
@@ -108,6 +109,7 @@ For cloud sandboxes such as Modal and Daytona, `container_persistent: true` mean
 | **modal** | Modal cloud sandbox | Full (cloud VM) | Ephemeral cloud compute, evals |
 | **daytona** | Daytona workspace | Full (cloud container) | Managed cloud dev environments |
 | **singularity** | Singularity/Apptainer container | Namespaces (--containall) | HPC clusters, shared machines |
+| **koyeb** | Koyeb cloud sandbox | Full (cloud sandbox) | Serverless cloud execution |
 
 ### Local Backend
 
@@ -242,6 +244,28 @@ terminal:
 
 **Isolation:** Uses `--containall --no-home` for full namespace isolation without mounting the host home directory.
 
+### Koyeb Backend
+
+Runs commands in a [Koyeb](https://www.koyeb.com) cloud sandbox. Each task gets an isolated sandbox that is deleted on cleanup.
+
+```yaml
+terminal:
+  backend: koyeb
+  koyeb_image: "koyeb/sandbox:latest"
+```
+
+**Required:** `KOYEB_API_TOKEN` environment variable. Get one from the [Koyeb control panel](https://app.koyeb.com/account/api).
+
+**Install the SDK:**
+
+```bash
+pip install "hermes-agent[koyeb]"
+```
+
+**Lifecycle:** A new sandbox is created for each task and deleted when the agent cleans up. There is no persistent state between sessions.
+
+**File sync:** `~/.hermes/` credentials and skills are synced to the sandbox via a single tarball upload for fast initialization.
+
 ### Common Terminal Backend Issues
 
 If terminal commands fail immediately or the terminal tool is reported as disabled:
@@ -252,6 +276,7 @@ If terminal commands fail immediately or the terminal tool is reported as disabl
 - **Modal** — Needs `MODAL_TOKEN_ID` env var or `~/.modal.toml`. Run `hermes doctor` to check.
 - **Daytona** — Needs `DAYTONA_API_KEY`. The Daytona SDK handles server URL configuration.
 - **Singularity** — Needs `apptainer` or `singularity` in `$PATH`. Common on HPC clusters.
+- **Koyeb** — Needs `KOYEB_API_TOKEN` and `pip install koyeb-sdk`. Run `hermes doctor` to check.
 
 When in doubt, set `terminal.backend` back to `local` and verify that commands run there first.
 
diff --git a/website/docs/user-guide/features/tools.md b/website/docs/user-guide/features/tools.md
index 2283c16fb4..4174e80add 100644
--- a/website/docs/user-guide/features/tools.md
+++ b/website/docs/user-guide/features/tools.md
@@ -64,13 +64,14 @@ The terminal tool can execute commands in different environments:
 | `singularity` | HPC containers | Cluster computing, rootless |
 | `modal` | Cloud execution | Serverless, scale |
 | `daytona` | Cloud sandbox workspace | Persistent remote dev environments |
+| `koyeb` | Koyeb cloud sandbox | Serverless cloud execution |
 
 ### Configuration
 
 ```yaml
 # In ~/.hermes/config.yaml
 terminal:
-  backend: local    # or: docker, ssh, singularity, modal, daytona
+  backend: local    # or: docker, ssh, singularity, modal, daytona, koyeb
   cwd: "."          # Working directory
   timeout: 180      # Command timeout in seconds
 ```
@@ -123,7 +124,7 @@ Configure CPU, memory, disk, and persistence for all container backends:
 
 ```yaml
 terminal:
-  backend: docker  # or singularity, modal, daytona
+  backend: docker  # or singularity, modal, daytona, koyeb
   container_cpu: 1              # CPU cores (default: 1)
   container_memory: 5120        # Memory in MB (default: 5GB)
   container_disk: 51200         # Disk in MB (default: 50GB)