Authoring

Build a workout, edit JSON, or use AI as the co-author.

Start from guided controls, paste an existing Universal Fit plan schema, or copy a focused prompt when you want an LLM to change the workout safely.

1. Copy the prompt

The prompt includes the rules the app expects: one JSON object, schema version 1.0, and no unknown top-level fields.

2. Paste into an LLM

Use your preferred assistant and describe your goal, schedule, equipment, and level.

ChatGPT Claude

3. Validate and save

The validator catches schema problems before the JSON ever reaches the app.

Read the brief

Workout builder

Build and reshape the plan before it reaches the app.

Use the builder for a valid starter file, paste an existing plan JSON to edit it, then download or copy the result once it passes schema validation.

Plan nameGoal

LevelFocus

WeeksDays/week

MinutesRest seconds

Equipment tagsUnits

Ready to import

Valid

Custom Workout Plan

4 weeks, 3 days/week, beginner

4weeks

3days

12sessions

Workout JSON editor

{
  "schema_version": "1.0",
  "plan": {
    "id": "custom-workout-plan-4wk",
    "name": "Custom Workout Plan",
    "author": "Universal Fit builder",
    "description": "4-week hybrid plan built from the website workout builder.",
    "goal": "general fitness",
    "level": "beginner",
    "duration_weeks": 4,
    "days_per_week": 3,
    "tags": [
      "hybrid",
      "general fitness",
      "beginner",
      "dumbbells",
      "running shoes"
    ]
  },
  "settings": {
    "units": {
      "weight": "kg",
      "distance": "km"
    },
    "rest_default_seconds": 120
  },
  "weeks": [
    {
      "week": 1,
      "name": "Week 1",
      "days": [
        {
          "day": 1,
          "name": "Lower Strength",
          "tags": [
            "strength",
            "lower-body"
          ],
          "estimated_minutes": 45,
          "blocks": [
            {
              "type": "main",
              "name": "Lower Strength",
              "items": [
                {
                  "kind": "exercise",
                  "exercise_ref": "goblet_squat",
                  "sets_template": {
                    "count": 3,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "romanian_deadlift",
                  "sets_template": {
                    "count": 3,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "walking_lunge",
                  "sets_template": {
                    "count": 2,
                    "set": {
                      "reps": "10 per side",
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 90
                    }
                  }
                }
              ]
            }
          ]
        },
        {
          "day": 3,
          "name": "Easy Run",
          "tags": [
            "running",
            "aerobic"
          ],
          "estimated_minutes": 45,
          "blocks": [
            {
              "type": "main",
              "name": "Easy Run",
              "items": [
                {
                  "kind": "exercise",
                  "exercise_ref": "running",
                  "cardio": {
                    "structure": "steady",
                    "modality": "running",
                    "target": {
                      "duration_minutes": 50,
                      "hr_zone": 2
                    }
                  }
                }
              ]
            }
          ]
        },
        {
          "day": 5,
          "name": "Upper Strength",
          "tags": [
            "strength",
            "upper-body"
          ],
          "estimated_minutes": 45,
          "blocks": [
            {
              "type": "main",
              "name": "Upper Strength",
              "items": [
                {
                  "kind": "exercise",
                  "exercise_ref": "dumbbell_bench_press",
                  "sets_template": {
                    "count": 3,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "one_arm_dumbbell_row",
                  "sets_template": {
                    "count": 3,
                    "set": {
                      "reps": "10 per side",
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "dumbbell_shoulder_press",
                  "sets_template": {
                    "count": 2,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 90
                    }
                  }
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "week": 2,
      "name": "Week 2",
      "days": [
        {
          "day": 1,
          "name": "Lower Strength",
          "tags": [
            "strength",
            "lower-body"
          ],
          "estimated_minutes": 45,
          "blocks": [
            {
              "type": "main",
              "name": "Lower Strength",
              "items": [
                {
                  "kind": "exercise",
                  "exercise_ref": "goblet_squat",
                  "sets_template": {
                    "count": 3,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "romanian_deadlift",
                  "sets_template": {
                    "count": 3,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "walking_lunge",
                  "sets_template": {
                    "count": 2,
                    "set": {
                      "reps": "10 per side",
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 90
                    }
                  }
                }
              ]
            }
          ]
        },
        {
          "day": 3,
          "name": "Easy Run",
          "tags": [
            "running",
            "aerobic"
          ],
          "estimated_minutes": 45,
          "blocks": [
            {
              "type": "main",
              "name": "Easy Run",
              "items": [
                {
                  "kind": "exercise",
                  "exercise_ref": "running",
                  "cardio": {
                    "structure": "steady",
                    "modality": "running",
                    "target": {
                      "duration_minutes": 52,
                      "hr_zone": 2
                    }
                  }
                }
              ]
            }
          ]
        },
        {
          "day": 5,
          "name": "Upper Strength",
          "tags": [
            "strength",
            "upper-body"
          ],
          "estimated_minutes": 45,
          "blocks": [
            {
              "type": "main",
              "name": "Upper Strength",
              "items": [
                {
                  "kind": "exercise",
                  "exercise_ref": "dumbbell_bench_press",
                  "sets_template": {
                    "count": 3,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "one_arm_dumbbell_row",
                  "sets_template": {
                    "count": 3,
                    "set": {
                      "reps": "10 per side",
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "dumbbell_shoulder_press",
                  "sets_template": {
                    "count": 2,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 90
                    }
                  }
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "week": 3,
      "name": "Week 3",
      "days": [
        {
          "day": 1,
          "name": "Lower Strength",
          "tags": [
            "strength",
            "lower-body"
          ],
          "estimated_minutes": 45,
          "blocks": [
            {
              "type": "main",
              "name": "Lower Strength",
              "items": [
                {
                  "kind": "exercise",
                  "exercise_ref": "goblet_squat",
                  "sets_template": {
                    "count": 4,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "romanian_deadlift",
                  "sets_template": {
                    "count": 4,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "walking_lunge",
                  "sets_template": {
                    "count": 3,
                    "set": {
                      "reps": "10 per side",
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 90
                    }
                  }
                }
              ]
            }
          ]
        },
        {
          "day": 3,
          "name": "Easy Run",
          "tags": [
            "running",
            "aerobic"
          ],
          "estimated_minutes": 45,
          "blocks": [
            {
              "type": "main",
              "name": "Easy Run",
              "items": [
                {
                  "kind": "exercise",
                  "exercise_ref": "running",
                  "cardio": {
                    "structure": "steady",
                    "modality": "running",
                    "target": {
                      "duration_minutes": 54,
                      "hr_zone": 2
                    }
                  }
                }
              ]
            }
          ]
        },
        {
          "day": 5,
          "name": "Upper Strength",
          "tags": [
            "strength",
            "upper-body"
          ],
          "estimated_minutes": 45,
          "blocks": [
            {
              "type": "main",
              "name": "Upper Strength",
              "items": [
                {
                  "kind": "exercise",
                  "exercise_ref": "dumbbell_bench_press",
                  "sets_template": {
                    "count": 4,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "one_arm_dumbbell_row",
                  "sets_template": {
                    "count": 4,
                    "set": {
                      "reps": "10 per side",
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "dumbbell_shoulder_press",
                  "sets_template": {
                    "count": 3,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 7
                      },
                      "rest_seconds": 90
                    }
                  }
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "week": 4,
      "name": "Deload and consolidate",
      "deload": true,
      "days": [
        {
          "day": 1,
          "name": "Easy Lower Strength",
          "tags": [
            "strength",
            "lower-body"
          ],
          "estimated_minutes": 35,
          "blocks": [
            {
              "type": "main",
              "name": "Lower Strength",
              "items": [
                {
                  "kind": "exercise",
                  "exercise_ref": "goblet_squat",
                  "sets_template": {
                    "count": 2,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 6
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "romanian_deadlift",
                  "sets_template": {
                    "count": 2,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 6
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "walking_lunge",
                  "sets_template": {
                    "count": 2,
                    "set": {
                      "reps": "10 per side",
                      "load": {
                        "rpe": 6
                      },
                      "rest_seconds": 90
                    }
                  }
                }
              ]
            }
          ]
        },
        {
          "day": 3,
          "name": "Easy Run",
          "tags": [
            "running",
            "aerobic"
          ],
          "estimated_minutes": 35,
          "blocks": [
            {
              "type": "main",
              "name": "Easy Run",
              "items": [
                {
                  "kind": "exercise",
                  "exercise_ref": "running",
                  "cardio": {
                    "structure": "steady",
                    "modality": "running",
                    "target": {
                      "duration_minutes": 56,
                      "hr_zone": 2
                    }
                  }
                }
              ]
            }
          ]
        },
        {
          "day": 5,
          "name": "Easy Upper Strength",
          "tags": [
            "strength",
            "upper-body"
          ],
          "estimated_minutes": 35,
          "blocks": [
            {
              "type": "main",
              "name": "Upper Strength",
              "items": [
                {
                  "kind": "exercise",
                  "exercise_ref": "dumbbell_bench_press",
                  "sets_template": {
                    "count": 2,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 6
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "one_arm_dumbbell_row",
                  "sets_template": {
                    "count": 2,
                    "set": {
                      "reps": "10 per side",
                      "load": {
                        "rpe": 6
                      },
                      "rest_seconds": 120
                    }
                  }
                },
                {
                  "kind": "exercise",
                  "exercise_ref": "dumbbell_shoulder_press",
                  "sets_template": {
                    "count": 2,
                    "set": {
                      "reps": 8,
                      "load": {
                        "rpe": 6
                      },
                      "rest_seconds": 90
                    }
                  }
                }
              ]
            }
          ]
        }
      ]
    }
  ]
}