Implementation:PrefectHQ Prefect Prefect Yaml Schema

Knowledge Sources	PrefectHQ_Prefect Prefect Docs JSON Schema
Domains	Configuration, Deployment, Schema_Validation
Last Updated	2026-02-09 22:00 GMT

Overview

JSON Schema definition that validates `prefect.yaml` deployment configuration files, enabling IDE autocompletion and static validation.

Description

The prefect.yaml.schema.json file defines the formal JSON Schema for Prefect deployment configuration files (`prefect.yaml`). It provides complete type definitions for DeploymentConfig (name, version, schedules, parameters, work pool, triggers, concurrency limits), schedule types (CronSchedule, IntervalSchedule, RRuleSchedule), ConcurrencyLimitSpec, and related configuration objects. Each property includes type constraints, defaults, and descriptions that enable IDE-based validation and autocompletion.

Usage

This schema is consumed by IDEs (VS Code, PyCharm) and JSON Schema validators when editing `prefect.yaml` files. Reference the schema in a `prefect.yaml` file to get autocompletion and inline validation of deployment configurations.

Code Reference

Source Location

• Repository: PrefectHQ_Prefect
• File: schemas/prefect.yaml.schema.json
• Lines: 1-938

Signature

{
    "$defs": {
        "ConcurrencyLimitSpec": {
            "properties": {
                "limit": { "type": ["integer", "null"], "default": null },
                "collision_strategy": { "type": ["string", "null"], "default": null },
                "grace_period_seconds": { "type": ["integer", "null"], "default": null }
            }
        },
        "CronSchedule": { ... },
        "IntervalSchedule": { ... },
        "RRuleSchedule": { ... },
        "DeploymentConfig": {
            "properties": {
                "name": { "type": "string" },
                "version": { "type": ["string", "null"] },
                "schedules": { "type": "array" },
                "parameters": { "type": "object" },
                "work_pool": { "type": "object" },
                "triggers": { "type": "array" },
                "concurrency_limit": { "$ref": "#/$defs/ConcurrencyLimitSpec" }
            }
        }
    }
}

Import

# Reference in prefect.yaml for IDE validation:
# yaml-language-server: $schema=./schemas/prefect.yaml.schema.json

# Or generate programmatically:
# python scripts/generate_prefect_yaml_schema.py

I/O Contract

Inputs

Name	Type	Required	Description
$defs	object	Yes	Schema definitions for all referenced types
DeploymentConfig	object	Yes	Main deployment configuration schema
CronSchedule	object	No	Cron-based schedule definition
IntervalSchedule	object	No	Interval-based schedule definition
RRuleSchedule	object	No	RFC 5545 recurrence rule schedule definition
ConcurrencyLimitSpec	object	No	Concurrency limit configuration

Outputs

Name	Type	Description
Validation results	boolean	Whether a prefect.yaml file conforms to the schema
IDE autocompletion	UI hints	Property suggestions and type information in editors

Usage Examples

Validated prefect.yaml

# prefect.yaml validated against the schema
deployments:
  - name: my-deployment
    version: "1.0.0"
    entrypoint: flows/my_flow.py:my_flow
    work_pool:
      name: my-pool
    schedules:
      - cron: "0 * * * *"
        timezone: "America/New_York"
    concurrency_limit:
      limit: 5
      collision_strategy: "ENQUEUE"

Related Pages

• Environment:PrefectHQ_Prefect_Python_Runtime_Environment