Image Metadata
Metadata lets you attach custom key-value pairs to images in your Roboflow workspace. Use metadata to store structured information alongside your images -- such as capture conditions, device identifiers, quality scores, or any domain-specific attributes -- and then search, filter, and organize your data around those attributes.
Overview
Each image can hold any number of metadata entries. An entry is a key (a name like camera_id) paired with a value (a string, number, or boolean).
| Value type | Examples |
|---|---|
| String | location: "warehouse-3", shift: "night" |
| Number | temperature: 72.5, quality_score: 95 |
| Boolean | reviewed: true, is_night: false |
Use cases
- Capture context -- record camera ID, GPS coordinates, weather, lighting conditions
- Quality tracking -- attach confidence scores, review status, annotator IDs
- Data slicing -- filter your dataset by any attribute to build targeted training sets
- External system linking -- store identifiers that connect images back to your internal tools
Adding Metadata
You can add metadata to images through the web UI, the Python SDK, the REST API, or automatically via S3 Bucket Mirror.
Web Application
- Open any image in your project.
- In the metadata section, enter a key in the first input and a value in the second input.
- Press Enter to save or click on Add.
Values are automatically parsed by type:
| Value entered | Stored as |
|---|---|
front | "front" (string) |
95 | 95 (number) |
3.14 | 3.14 (number) |
true / false | true / false (boolean) |
Python SDK
Pass a metadata dictionary when uploading an image:
import roboflow
rf = roboflow.Roboflow(api_key="YOUR_API_KEY")
project = rf.workspace("your-workspace").project("your-project")
project.upload(
image_path="image.jpg",
metadata={
"camera_id": "cam001",
"location": "warehouse-3",
"temperature": 72.5,
"is_night": False
}
)
REST API
Add metadata during upload
Include a metadata field (JSON-stringified) in the multipart form data when uploading an image:
curl -X POST "https://api.roboflow.com/dataset/your-dataset/upload?api_key=YOUR_API_KEY" \
-F "name=image.jpg" \
-F "split=train" \
-F "file=@image.jpg" \
-F 'metadata={"camera_id":"cam001","temperature":72.5}'
S3 Bucket Mirror
When using Bucket Mirror to sync images from an S3 bucket, you can attach metadata by placing a .json file alongside each image with the same base name:
my-bucket/
images/
photo_001.jpg
photo_001.json # metadata for photo_001.jpg
photo_002.jpg
photo_002.json # metadata for photo_002.jpg
The JSON file contains your metadata as key-value pairs:
{
"camera_id": "cam001",
"location": "warehouse-3",
"capture": { "temperature": 72.5, "humidity": 45 }
}
Nested objects are automatically flattened using dot notation. The example above produces:
| Key | Value |
|---|---|
camera_id | "cam001" |
location | "warehouse-3" |
capture.temperature | 72.5 |
capture.humidity | 45 |
Metadata file constraints
- Maximum file size: 256 KB
- Must be valid JSON
nullandundefinedvalues are filtered out
Update strategies
Bucket Mirror supports different strategies for how synced metadata interacts with metadata you've set manually in the UI or via API:
| Strategy | Behavior |
|---|---|
mergeBucketWins (default) | Merges both sources. On key conflicts, the bucket value wins. |
mergeUserWins | Merges both sources. On key conflicts, the user-set value wins. |
overwrite | Bucket metadata completely replaces all existing metadata. |
untilFirstChange | Syncs from bucket until a user manually edits metadata, then stops updating. |
append | Only adds new keys from the bucket. Never overwrites existing keys. |
Searching by Metadata
Metadata is indexed and searchable in the Asset Library. Use the search bar to filter images by metadata values:
metadata.camera_id:"cam001"
metadata.quality_score>80
metadata.reviewed:true
You can combine metadata filters with other search filters:
metadata.location:"warehouse-3" AND class:forklift
The Asset Library also provides autocomplete for metadata keys and values based on what exists in your workspace.
Key Naming Rules
Metadata keys must follow these rules:
| Rule | Detail |
|---|---|
| Allowed characters | Letters (a-z, A-Z), numbers (0-9), underscores (_), dots (.) |
| First character | Must be a letter, number, or underscore |
| Forbidden characters | Forward slashes (/) are not allowed |
Valid keys: camera_id, capture.temperature, _internal_ref, v2_score
Invalid keys: camera/id (contains /), .starts_with_dot (starts with .), has spaces (contains spaces)
Metadata vs. Tags
Both metadata and tags help you organize images, but they serve different purposes:
| Tags | Metadata | |
|---|---|---|
| Structure | Simple labels | Key-value pairs |
| Values | No value, just a name | String, number, or boolean |
| Best for | Categorization, workflow status | Structured attributes, measurements |
| Example | reviewed, v2, needs-annotation | temperature: 72.5, camera_id: "cam001" |
You can use both on the same image. For example, tag an image as reviewed and also store reviewer: "alice" and confidence: 0.95 as metadata.