<!-- source: https://secondlayer.tools/docs/api-reference#bundle-subgraph -->

## Bundle subgraph source into deployable handler code

`POST /api/subgraphs/bundle` (self-hosted instances only)

Compiles a TypeScript subgraph module on the server and returns the bundle plus the metadata read from it, ready to POST to `/api/subgraphs`. Deploys nothing. The CLI and MCP bundle locally; this is for callers that cannot run esbuild.

### Body

| Field | Type | Description |
| --- | --- | --- |
| `code` | string, required | The subgraph module's TypeScript source, with `defineSubgraph` as the default export. |

### Returns

One `SubgraphBundle` object.

### Responses

- `200` Bundled
- `400` `code` is missing or empty, or the module did not compile (`BUNDLE_FAILED`)
- `401` This bind requires the instance token, and it was missing or wrong
- `413` The bundle exceeds the size limit (`BUNDLE_TOO_LARGE`); `actualBytes` and `maxBytes` say by how much
- `415` Missing or non-JSON `Content-Type` (`UNSUPPORTED_MEDIA_TYPE`) — writes must send `Content-Type: application/json`

### Example

```bash
curl -X POST http://127.0.0.1:3800/api/subgraphs/bundle \
  -H "Authorization: Bearer $INSTANCE_TOKEN" \
  --json '{
  "code": "import { defineSubgraph } from \"@secondlayer/subgraphs\";\n\nexport default defineSubgraph({\n  name: \"sbtc-flows\",\n  startBlock: 8000000,\n  sources: {\n    transfers: {\n      type: \"ft_transfer\",\n      assetIdentifier: \"SM3VDXK3WZZSA84XXFKAFAF15NNZX32CTSG82JFQ4.sbtc-token::sbtc-token\",\n    },\n  },\n  schema: {\n    transfers: {\n      columns: {\n        amount: { type: \"uint\" },\n        sender: { type: \"principal\" },\n        recipient: { type: \"principal\" },\n      },\n    },\n  },\n  handlers: {\n    transfers: (event, ctx) => {\n      ctx.insert(\"transfers\", { amount: event.amount, sender: event.sender, recipient: event.recipient });\n    },\n  },\n});\n"
}'
```

```json
{
  "ok": true,
  "name": "sbtc-flows",
  "description": null,
  "sources": {
    "transfers": {
      "type": "ft_transfer",
      "assetIdentifier": "SM3VDXK3WZZSA84XXFKAFAF15NNZX32CTSG82JFQ4.sbtc-token::sbtc-token"
    }
  },
  "schema": {
    "transfers": {
      "columns": {
        "amount": {
          "type": "uint"
        },
        "sender": {
          "type": "principal"
        },
        "recipient": {
          "type": "principal"
        }
      }
    }
  },
  "handlerCode": "// secondlayer-stub:@secondlayer/subgraphs\nfunction defineSubgraph(def) {\n  return def;\n}\n\n// <stdin>\nvar stdin_default = defineSubgraph({\n  name: \"sbtc-flows\",\n  startBlock: 8e6,\n  sources: {\n    transfers: {\n      type: \"ft_transfer\",\n      assetIdentifier: \"SM3VDXK3WZZSA84XXFKAFAF15NNZX32CTSG82JFQ4.sbtc-token::sbtc-token\"\n    }\n  },\n  schema: {\n    transfers: {\n      columns: {\n        amount: { type: \"uint\" },\n        sender: { type: \"principal\" },\n        recipient: { type: \"principal\" }\n      }\n    }\n  },\n  handlers: {\n    transfers: (event, ctx) => {\n      ctx.insert(\"transfers\", { amount: event.amount, sender: event.sender, recipient: event.recipient });\n    }\n  }\n});\nexport {\n  stdin_default as default\n};\n",
  "sourceCode": "import { defineSubgraph } from \"@secondlayer/subgraphs\";\n\nexport default defineSubgraph({\n  name: \"sbtc-flows\",\n  startBlock: 8000000,\n  sources: {\n    transfers: {\n      type: \"ft_transfer\",\n      assetIdentifier: \"SM3VDXK3WZZSA84XXFKAFAF15NNZX32CTSG82JFQ4.sbtc-token::sbtc-token\",\n    },\n  },\n  schema: {\n    transfers: {\n      columns: {\n        amount: { type: \"uint\" },\n        sender: { type: \"principal\" },\n        recipient: { type: \"principal\" },\n      },\n    },\n  },\n  handlers: {\n    transfers: (event, ctx) => {\n      ctx.insert(\"transfers\", { amount: event.amount, sender: event.sender, recipient: event.recipient });\n    },\n  },\n});\n",
  "bundleSize": 724
}
```