Trailers

Fleet-Ops models a Trailer as a first-class fleet resource. A trailer has its own identity, lifecycle, dimensions, maintenance history, equipment, devices, and location even though it cannot move under its own power. This keeps semitrailers, flatbeds, tankers, chassis, reefers, dollies, and other towed assets separate from both powered Vehicles and auxiliary Equipment.

Choose Resources → Trailers, directly below Vehicles, to create and manage trailers.

When to use each resource

Do not create a tractor head as a Trailer. A head or tractor is a Vehicle, and its current towing relationship points to one or more Trailer records.

Trailer data

Trailer records support:

• identity and registration: name, code, VIN, plate and serial number, make, model, and year;
• classification: dry_van, reefer, flatbed, step_deck, lowboy, tanker, bulk, dump, chassis, curtain_side, car_carrier, livestock, logging, dolly, specialty, or other;
• lifecycle status: available, in_use, maintenance, out_of_service, or retired — attachment state and connectivity are derived separately and never overwrite the lifecycle status;
• physical specifications in the trailer's measurement system (metric or imperial): length, width, height, tare weight, gross vehicle weight rating, payload capacity, cargo volume, axles, tires, doors, coupling type, brake type, ABS and EBS;
• reefer details: refrigerated flag, temperature range, and reefer engine hours;
• ownership and finance: ownership type, financing status, purchase and lease dates, currency, acquisition cost, current value, insured value, depreciation rate, vendor, warranty, photo, notes, and custom fields;
• the current towing vehicle and the complete towing history;
• attached devices and equipment;
• location, connectivity, maintenance schedules, work orders, and maintenance history.

The console form only shows the reefer section for refrigerated trailers and the lease expiry for leased, rented, or financed trailers, and it labels every dimensional field with the unit implied by the measurement system.

Lifecycle

1. Create or import the Trailer.
2. Attach equipment and a telematics device when applicable.
3. Attach the Trailer to a Vehicle when a towing movement starts.
4. Track it directly through its device or the Trailer tracking API.
5. Detach it when the movement ends. Fleet-Ops preserves the completed connection in the towing history.
6. Schedule inspections and maintenance against the Trailer itself.

A Trailer cannot be deleted while it is attached to a vehicle. Detach it first so the operational history remains accurate; the API answers 409 Conflict until you do, and bulk deletion in the console skips attached trailers.

API

Trailers are exposed at /v1/trailers and use the trailer_ public identifier. Responses never include private UUIDs.

Create a trailer

curl -X POST https://api.fleetbase.io/v1/trailers \
  -H "Authorization: Bearer $FLEETBASE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Reefer 12",
    "code": "TRL-0012",
    "type": "reefer",
    "status": "available",
    "plate_number": "TR-1200",
    "measurement_system": "metric",
    "payload_capacity": 20000,
    "axle_count": 2,
    "refrigerated": true,
    "temperature_min": -20,
    "temperature_max": 4
  }'

{
  "id": "trailer_7YqM3KpL2n",
  "asset_class": "trailer",
  "name": "Reefer 12",
  "display_name": "Reefer 12",
  "code": "TRL-0012",
  "type": "reefer",
  "status": "available",
  "attachment_state": "detached",
  "connectivity_status": "never_connected",
  "online": null,
  "plate_number": "TR-1200",
  "category_id": null,
  "vendor_id": null,
  "warranty_id": null,
  "photo_id": null,
  "vehicle_id": null,
  "current_vehicle": null,
  "current_connection": null,
  "connections": [],
  "devices": [],
  "equipment": [],
  "devices_count": 0,
  "equipment_count": 0,
  "measurement_system": "metric",
  "payload_capacity": "20000.000",
  "axle_count": 2,
  "refrigerated": true,
  "temperature_min": "-20.000",
  "temperature_max": "4.000",
  "location": { "type": "Point", "coordinates": [0, 0] },
  "telematics": null,
  "created_at": "2026-09-07T11:35:32.000000Z",
  "updated_at": "2026-09-07T11:35:32.000000Z"
}

Relationship identifiers (category_id, vendor_id, warranty_id, photo_id, and vehicle_id) are always present so a write can be read back. Pass the related public ID under category, vendor, warranty, or photo when creating or updating; send null to clear one.

Expand related objects

Use with (or expand) to include the related object beside its identifier. Supported expansions are category, vendor, warranty, photo, and positions; unknown names are ignored.

curl "https://api.fleetbase.io/v1/trailers/trailer_7YqM3KpL2n?with=vendor,category" \
  -H "Authorization: Bearer $FLEETBASE_API_KEY"

The towing state (current_vehicle, current_connection, connections), attached devices, and attached equipment are part of the base representation and are always included.

List and filter

curl "https://api.fleetbase.io/v1/trailers?type=reefer&attachment_state=detached&connectivity_status=online&limit=25&sort=-created_at" \
  -H "Authorization: Bearer $FLEETBASE_API_KEY"

Supported filters include query, type, status, attachment_state (attached or detached), connectivity_status (online, recently_offline, offline, never_connected), vehicle (the towing vehicle's public ID), vendor, category, plate_number, vin, refrigerated, ownership_type, created_at, updated_at, and last_online_at.

Update and delete

PUT /v1/trailers/{id} accepts the same fields as create. DELETE /v1/trailers/{id} soft-deletes a detached trailer and returns 409 Conflict for an attached one.

Related pages

• Connections and equipment
• Trailer telematics
• Vehicles
• Maintenance