> For the complete documentation index, see [llms.txt](https://docs.roboflow.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.roboflow.com/workflows/developer-guide.md).

# Developer Guide

- [Developer Guide](https://docs.roboflow.com/workflows/developer-guide/developer-guide.md): Reference for developers extending Workflows - the pillars of the ecosystem, the Definition language, the Compiler and Execution Engine, kinds, and how to write your own blocks.
- [Workflow Definition syntax](https://docs.roboflow.com/workflows/developer-guide/developer-guide/definitions.md): The Workflow Definition JSON syntax: version marker, inputs, steps, selectors, and outputs.
- [Workflow execution](https://docs.roboflow.com/workflows/developer-guide/developer-guide/workflow-execution.md): How a Workflow runs: compilation, batch-oriented data, dimensionality levels, conditional execution, and output construction.
- [Kinds](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds.md): Kinds are the Workflows type system: the semantic meaning and data representation behind every connection.
- [barcodedetection Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/bar-code-detection.md): Prediction with barcode detection.
- [boolean Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/boolean.md): Boolean flag.
- [bytes Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/bytes.md): This kind represent bytes.
- [classificationprediction Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/classification-prediction.md): Predictions from classifier.
- [contours Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/contours.md): List of numpy arrays where each array represents contour points.
- [detection Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/detection.md): Single element of detections-based prediction (like \`object\_detection\_prediction\`).
- [detectionsoverlaps Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/detections-overlaps.md): List of per-pair detection overlap records.
- [dictionary Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/dictionary.md): Dictionary.
- [embedding Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/embedding.md): A list of floating point numbers representing a vector embedding.
- [floatzerotoone Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/float-zero-to-one.md): \`float\` value in range \`\[0.0, 1.0]\`.
- [float Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/float.md): Float value.
- [imagekeypoints Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/image-keypoints.md): Image keypoints detected by classical Computer Vision method.
- [imagemetadata Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/image-metadata.md): Dictionary with image metadata required by supervision.
- [image Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/image.md): Image in workflows.
- [inferenceid Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/inference-id.md): Inference identifier.
- [instancesegmentationprediction Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/instance-segmentation-prediction.md): Prediction with detected bounding boxes and segmentation masks in form of sv.Detections(...) object.
- [integer Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/integer.md): Integer value.
- [keypointdetectionprediction Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/keypoint-detection-prediction.md): Prediction with detected bounding boxes and detected keypoints in form of sv.Detections(...) object.
- [labeledpoints Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/labeled-points.md): List of 2D points with positive/negative labels.
- [languagemodeloutput Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/language-model-output.md): LLM / VLM output.
- [listofvalues Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/list-of-values.md): List of values of any type.
- [numpyarray Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/numpy-array.md): Numpy array.
- [objectdetectionprediction Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/object-detection-prediction.md): Prediction with detected bounding boxes in form of sv.Detections(...) object.
- [parentid Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/parent-id.md): Identifier of parent for step output.
- [point Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/point.md): Single point in 2D.
- [predictiontype Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/prediction-type.md): String value with type of prediction.
- [qrcodedetection Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/qr-code-detection.md): Prediction with QR code detection.
- [rgbcolor Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/rgb-color.md): RGB color.
- [rleinstancesegmentationprediction Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/rle-instance-segmentation-prediction.md): Prediction with detected bounding boxes and RLE-encoded segmentation masks in form of sv.Detections(...) object.
- [roboflowapikey Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/roboflow-api-key.md): Roboflow API key.
- [ROBOFLOWMANAGEDKEY Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/roboflow-managed-key.md): Roboflow-managed key or credential.
- [roboflowmodelid Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/roboflow-model-id.md): Roboflow model id.
- [roboflowproject Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/roboflow-project.md): Roboflow project name.
- [roboflowsolution Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/roboflow-solution.md): Roboflow Vision Events use case identifier.
- [secret Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/secret.md): Secret value.
- [semanticsegmentationprediction Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/semantic-segmentation-prediction.md): Prediction with per-pixel class label and confidence for semantic segmentation.
- [serialisedpayloads Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/serialised-payloads.md): Serialised element that is usually accepted by sink.
- [string Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/string.md): String value.
- [timestamp Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/timestamp.md): Timestamp object.
- [topclass Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/top-class.md): String value representing top class predicted by classification model.
- [videometadata Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/video-metadata.md): Video image metadata.
- [Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/wildcard.md): Equivalent of any element.
- [zone Kind](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/zone.md): Definition of polygon zone.
- [Data representations](https://docs.roboflow.com/workflows/developer-guide/developer-guide/data-representations.md): The Python data types blocks receive at runtime: Batch, WorkflowImageData, and VideoMetadata.
- [Workflows Compiler](https://docs.roboflow.com/workflows/developer-guide/developer-guide/compiler.md): How the Workflows Compiler turns a Workflow Definition into an executable computation graph.
- [Execution Engine](https://docs.roboflow.com/workflows/developer-guide/developer-guide/execution-engine.md): Inside the Workflows Execution Engine: input validation, execution order, step inputs and outputs, and flow control.
- [Inner workflows](https://docs.roboflow.com/workflows/developer-guide/developer-guide/inner-workflows.md): Embed one Workflow definition inside another with the Inner workflow block, and how the compiler inlines it.
- [Execution Engine changelog](https://docs.roboflow.com/workflows/developer-guide/developer-guide/execution-engine-changelog.md): Version-by-version changes to the Workflows Execution Engine.
- [Versioning](https://docs.roboflow.com/workflows/developer-guide/developer-guide/versioning.md): How the Workflows Execution Engine, Workflow Definitions, and blocks are versioned.
- [Create a Workflow block](https://docs.roboflow.com/workflows/developer-guide/developer-guide/create-a-block.md): Full developer guide to writing a Workflow block: manifests, inputs, outputs, batch processing, flow control, and dimensionality.
- [Bundling blocks into a plugin](https://docs.roboflow.com/workflows/developer-guide/developer-guide/block-bundling.md): Package Workflow blocks into a plugin: required interface, kinds, initializers, serializers, and loading.
- [Dynamic Python blocks](https://docs.roboflow.com/workflows/developer-guide/developer-guide/dynamic-python-blocks.md): Define blocks in place in a Workflow Definition with Python code that the Execution Engine interprets at runtime.
- [Testing blocks](https://docs.roboflow.com/workflows/developer-guide/developer-guide/testing.md): Recommended unit and integration testing approach for Workflow blocks you build.
- [Community plugins](https://docs.roboflow.com/workflows/developer-guide/developer-guide/community-plugins.md): Community-built Workflow plugins that add blocks, models, and integrations to the ecosystem.
- [Workflows Schema API](https://docs.roboflow.com/workflows/developer-guide/developer-guide/schema-api.md): Programmatically describe a Workflow's inputs, outputs, typing hints, and kind schemas.
- [Workflow profiling](https://docs.roboflow.com/workflows/developer-guide/developer-guide/profiling.md): Measure Workflow execution timing and find bottlenecks with Chrome-compatible profiling traces.
- [Workflows benchmarks](https://docs.roboflow.com/workflows/developer-guide/developer-guide/benchmarks.md): Latency of direct model inference compared with the same model wrapped in a Workflow.