# Endpoints & base URLs

Source: https://docs.littlebigbrain.com/start/endpoints/

Every hosted stack has one canonical data-plane endpoint:

```
https://<tenant-short-id>--<stack-slug>.db.eu.littlebigbrain.com
```

Copy the complete `endpoint_url` from the console's **Connect** view. Do not
construct it from the stack name alone.

- `tenant-short-id` is the account's immutable, eight-character lowercase
  Crockford Base32 identifier, for example `0abc1def`.
- `stack-slug` is the account-scoped stack name, for example `product-dev`.
  Slugs can be reused by different accounts, but not twice in one account.

The examples in these docs use:

```
https://0abc1def--product-dev.db.eu.littlebigbrain.com
```

## What the endpoint selects

The hostname selects the account and stack. The `?graph=` query parameter, or
the matching SDK option, selects the graph.
Your stack API key must belong to the account and stack named by the host.

The endpoint stays stable if the stack's storage placement changes. A stack's
internal storage identity is independent of its public slug, so renaming the
slug never moves graph objects.

## The composite host is required

Application traffic must use the composite host. A missing or malformed stack
host returns `421 stack_endpoint_required`. Presenting a valid credential for
another stack returns `403 stack_endpoint_mismatch`. In either case, copy the
console-provided `endpoint_url`.

## TLS and health

Every stack endpoint is HTTPS-only and covered by the cell wildcard
certificate. Operational health checks use the exact hostname
`https://health.db.eu.littlebigbrain.com/healthz`, which reports cell health
only. Application traffic goes to the stack endpoint.

## Hosted MCP addressing

Hosted [MCP](https://docs.littlebigbrain.com/sdks/mcp/) uses a path form:

```
https://mcp.littlebigbrain.com/mcp/<stack-slug>
```

The slug is resolved within the WorkOS organization established by OAuth, so
two organizations can use the same slug without colliding.

## Base URL summary

| Purpose | URL |
| --- | --- |
| Hosted stack | `https://<tenant-short-id>--<stack-slug>.db.eu.littlebigbrain.com` |
| Hosted MCP | `https://mcp.littlebigbrain.com/mcp/<stack-slug>` |
| SaaS API | `https://api.littlebigbrain.com` |
| Console | `https://cloud.littlebigbrain.com` |
| Cell health | `https://health.db.eu.littlebigbrain.com/healthz` |

Next: run the [Quickstart](https://docs.littlebigbrain.com/start/quickstart/) or review
[Authentication & endpoints](https://docs.littlebigbrain.com/start/authentication/).