> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lerian.studio/llms.txt
> Use this file to discover all available pages before exploring further.

# Configuration and deploy

> How Lender is packaged and run — the container shape, its dependencies, a curated environment-variable surface, multi-tenant modes, and the ledger posting path.

export const GLedger = ({children}) => <Tooltip headline="Ledger" tip="The core financial book that records all transactions, balances, and operations for an organization — the single source of truth for a business unit's finances." cta="See glossary" href="/en/glossary">
    {children}
  </Tooltip>;

export const GKubernetes = ({children}) => <Tooltip headline="Kubernetes" tip="A platform for running and managing software applications at scale — it automatically handles deployment, scaling, and recovery across multiple servers." cta="See glossary" href="/en/glossary">
    {children}
  </Tooltip>;

Lender is a single Go service, packaged as a container and configured entirely through environment variables. This page is the operator's reference: what it runs as, what it depends on, the settings that matter, and how tenancy and ledger routing behave.

## The container

***

Lender builds from a multi-stage Dockerfile — a Go Alpine builder producing a static binary, copied into a distroless nonroot runtime — and listens on port `8080`. It ships as a container image you deploy into your <GKubernetes>Kubernetes</GKubernetes> cluster with the platform's standard [lifecycle tooling](/en/platform/lifecycle-management); this page does not assume any particular packaging beyond the image.

Operational probes:

| Endpoint       | Purpose                     |
| -------------- | --------------------------- |
| `GET /health`  | Liveness.                   |
| `GET /readyz`  | Dependency readiness.       |
| `GET /version` | Build and version metadata. |

## Dependencies

***

| Dependency                      | Role                                                                                                                                                                                                                                                                               |
| ------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **PostgreSQL 17**               | Primary data store, with primary/replica support and schema-per-tenant isolation in multi-tenant mode.                                                                                                                                                                             |
| **Valkey 8** (Redis-compatible) | Cache, rate limiting, and the M2M-credential cache.                                                                                                                                                                                                                                |
| **RabbitMQ**                    | Event publisher transport, driven by a transactional **outbox** dispatcher.                                                                                                                                                                                                        |
| **RedPanda**                    | Streaming backbone for the lifecycle event catalog (via Lerian's streaming library).                                                                                                                                                                                               |
| **Midaz**                       | The double-entry <GLedger>ledger</GLedger>, reached through the official SDK. Lender authenticates via [Access Manager](/en/platform/access-manager/access-manager) with per-tenant machine-to-machine (M2M) credentials, retrieved from AWS Secrets Manager and cached in Valkey. |
| **Casdoor**                     | Identity provider backing route authorization (via Lerian's auth library).                                                                                                                                                                                                         |
| **Systemplane**                 | Runtime configuration plane, mounted under `/api/v1/systemplane`.                                                                                                                                                                                                                  |

## Configuration surface

***

Configuration is entirely environment-driven. The keys below are a curated subset — the ones that shape behavior — not the full list.

| Group         | Key                                                                                                                            | What it controls                                                                       |
| ------------- | ------------------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------- |
| App           | `ENV_NAME`, `LOG_LEVEL`, `DEPLOYMENT_MODE`, `SERVER_ADDRESS`                                                                   | Environment name, log verbosity, deployment mode, and listen address.                  |
| Tenancy       | `MULTI_TENANT_ENABLED`, `DEFAULT_TENANT_ID`                                                                                    | Switch between single- and multi-tenant modes, and the tenant used when single-tenant. |
| Tenancy (MT)  | `MULTI_TENANT_MAX_TENANT_POOLS`, `MULTI_TENANT_CIRCUIT_BREAKER_THRESHOLD`                                                      | Per-tenant connection-pool ceiling and circuit-breaker trip point.                     |
| Postgres      | `POSTGRES_HOST`, `POSTGRES_PORT`, `POSTGRES_USER`, `POSTGRES_PASSWORD`, `POSTGRES_NAME`, `POSTGRES_SSLMODE`, `MIGRATIONS_PATH` | Primary database connection and migrations.                                            |
| Cache         | `REDIS_HOST`, `REDIS_PASSWORD`, `M2M_CREDENTIAL_CACHE_TTL_SEC`                                                                 | Valkey connection and how long M2M credentials are cached.                             |
| Messaging     | `RABBITMQ_ENABLED`, `RABBITMQ_HOST`, `OUTBOX_ENABLED`, `OUTBOX_DISPATCH_INTERVAL_SEC`                                          | RabbitMQ transport and the outbox dispatcher cadence.                                  |
| Streaming     | `STREAMING_ENABLED`, `STREAMING_BROKERS`, `STREAMING_TLS_ENABLED`                                                              | Event streaming toggle, broker addresses, and TLS.                                     |
| Auth          | `PLUGIN_AUTH_ENABLED`                                                                                                          | Enable route authorization against the identity provider.                              |
| Ledger M2M    | `AWS_REGION`                                                                                                                   | Region for the Secrets Manager holding per-tenant Midaz credentials.                   |
| Observability | `ENABLE_TELEMETRY`, `OTEL_EXPORTER_OTLP_ENDPOINT`                                                                              | Telemetry toggle and OTLP collector endpoint.                                          |
| Limits        | `RATE_LIMIT_ENABLED`                                                                                                           | Request rate limiting.                                                                 |
| Docs          | `SWAGGER_ENABLED`                                                                                                              | Serve the OpenAPI document and API reference UI.                                       |

## Multi-tenant modes

***

Lender runs in one of two modes:

* **Single-tenant** — one tenant (`DEFAULT_TENANT_ID`), one database schema, and a construction-time ledger organization and ledger used as the posting default.
* **Multi-tenant** (`MULTI_TENANT_ENABLED=true`) — **schema-per-tenant** persistence, a per-tenant Midaz client pool, and tenant-scoped events and postings. In this mode there is no env ledger default: the ledger target comes per transaction from the product's accounting profile.

## Ledger posting and fails-closed routing

***

Every financial event books to the ledger through a durable posting intent and an asynchronous relay — the full path is in [Lender in the platform](/en/lender/lender-in-the-platform). The operationally important property: **routing fails closed**. A posting books into the ledger organization and ledger resolved from the accounting profile (single-tenant falls back to the env default); if neither resolves a non-empty target, Lender **refuses to post** rather than book into an empty or wrong ledger. Under multi-tenant mode, a product with no accounting profile therefore cannot post — which is the intended safeguard.

## Next steps

***

<Card title="Lender in the platform" icon="sitemap" href="/en/lender/lender-in-the-platform" horizontal>
  The posting path, event catalog, and tenant isolation in detail.
</Card>