Convert JSON to Excel by Python

Here is the code what you are looking for. I did this using XlsxWriter package. First I made the template with some cell format stuff. After that, I entered values using according to your JSON.

import xlsxwriter
from itertools import zip_longest

data = [
    {
        "companyId": "123456",
        "companyName": "Test",
        "companyStatus": "ACTIVE",
        "document": {
            "employee": {
                "employeeId": "EM1567",
                "employeeLastName": "Test Last",
                "employeeFirstName": "Test Fist"
            },
            "expenseEntry": [
                {
                    "allocation": [
                        {
                            "allocationId": "03B249B3598",
                            "journal": [
                                {
                                    "journalAccountCode": "888",
                                    "journalPayee": "EMPL",
                                    "journalPayer": "COMP",
                                    "taxGuid": [
                                        "51645A638114E"
                                    ]
                                },
                                {
                                    "journalAccountCode": "999",
                                    "journalPayee": "EMPL",
                                    "journalPayer": "EMPL",
                                    "taxGuid": [
                                        "8114E51645A63"
                                    ]
                                },
                            ],
                            "tax": [
                                {
                                    "taxCode": "TAX123",
                                    "taxSource": "SYST"
                                },
                                {
                                    "taxCode": "TAX456",
                                    "taxSource": "SYST"
                                }
                            ]
                        }
                    ],
                    "approvedAmount": 200.0,
                    "entryDate": "2020-12-10",
                    "entryId": "ENTRY9988"
                }
            ],
            "report": {
                "currencyCode": "USD",
                "reportCreationDate": "2020-12-10",
                "reportId": "ACA849BBB",
                "reportName": "Test Report",
                "totalApprovedAmount": 200.0
            }
        },
        "id": "c71b7d756f549"
    }
]

xlsx_file = 'your_file_name_here.xlsx'

# define the excel file
workbook = xlsxwriter.Workbook(xlsx_file)

# create a sheet for our work, defaults to Sheet1.
worksheet = workbook.add_worksheet()

# common merge format
merge_format = workbook.add_format({'align': 'center', 'valign': 'vcenter'})

# set all column width to 20
worksheet.set_column('A:V', 20)

# column wise template creation (A-V)
worksheet.merge_range(0, 0, 4, 0, 'companyId', merge_format)  # A
worksheet.merge_range(0, 1, 4, 1, 'companyName', merge_format)  # B
worksheet.merge_range(0, 2, 4, 2, 'companyStatus', merge_format)  # C

worksheet.merge_range(0, 3, 0, 20, 'document', merge_format)  # C-U

worksheet.merge_range(1, 3, 1, 5, 'employee', merge_format)  # D-F
worksheet.merge_range(2, 3, 4, 3, 'employeeId', merge_format)  # D
worksheet.merge_range(2, 4, 4, 4, 'employeeLastName', merge_format)  # E
worksheet.merge_range(2, 5, 4, 5, 'employeeFirstName', merge_format)  # F

worksheet.merge_range(1, 6, 1, 15, 'expenseEntry', merge_format)  # G-P
worksheet.merge_range(2, 6, 2, 12, 'allocation', merge_format)  # G-M
worksheet.merge_range(3, 6, 4, 6, 'allocationId', merge_format)  # G

worksheet.merge_range(3, 7, 3, 10, 'journal', merge_format)  # H-K
worksheet.write(4, 7, 'journalAccountCode')  # H
worksheet.write(4, 8, 'journalPayee')  # I
worksheet.write(4, 9, 'journalPayer')  # J
worksheet.write(4, 10, 'taxGuid')  # K

worksheet.merge_range(3, 11, 3, 12, 'tax', merge_format)  # L-M
worksheet.write(4, 11, 'taxCode')  # L
worksheet.write(4, 12, 'taxSource')  # M

worksheet.merge_range(2, 13, 4, 13, 'approvedAmount', merge_format)  # N
worksheet.merge_range(2, 14, 4, 14, 'entryDate', merge_format)  # O
worksheet.merge_range(2, 15, 4, 15, 'entryId', merge_format)  # P

worksheet.merge_range(1, 16, 1, 20, 'report', merge_format)  # Q-U
worksheet.merge_range(2, 16, 4, 16, 'currencyCode', merge_format)  # Q
worksheet.merge_range(2, 17, 4, 17, 'reportCreationDate', merge_format)  # R
worksheet.merge_range(2, 18, 4, 18, 'reportId', merge_format)  # S
worksheet.merge_range(2, 19, 4, 19, 'reportName', merge_format)  # T
worksheet.merge_range(2, 20, 4, 20, 'totalApprovedAmount', merge_format)  # U

worksheet.merge_range(0, 21, 4, 21, 'id', merge_format)  # V

# inserting data
row = 5
for obj in data:
    worksheet.write(row, 0, obj.get('companyId'))
    worksheet.write(row, 1, obj.get('companyName'))
    worksheet.write(row, 2, obj.get('companyStatus'))

    document = obj.get('document', {})

    # employee details
    employee = document.get('employee', {})
    worksheet.write(row, 3, employee.get('employeeId'))
    worksheet.write(row, 4, employee.get('employeeLastName'))
    worksheet.write(row, 5, employee.get('employeeFirstName'))

    # report details
    report = document.get('report', {})
    worksheet.write(row, 16, report.get('currencyCode'))
    worksheet.write(row, 17, report.get('reportCreationDate'))
    worksheet.write(row, 18, report.get('reportId'))
    worksheet.write(row, 19, report.get('reportName'))
    worksheet.write(row, 20, report.get('totalApprovedAmount'))

    worksheet.write(row, 21, obj.get('id'))

    # expenseEntry details
    expense_entries = document.get('expenseEntry', [])
    for expense_entry in expense_entries:
        worksheet.write(row, 13, expense_entry.get('approvedAmount'))
        worksheet.write(row, 14, expense_entry.get('entryDate'))
        worksheet.write(row, 15, expense_entry.get('entryId'))

        # allocation details
        allocations = expense_entry.get('allocation', [])
        for allocation in allocations:
            worksheet.write(row, 6, allocation.get('allocationId'))

            # journal and tax details
            journals = allocation.get('journal', [])
            taxes = allocation.get('tax', [])
            for journal_and_tax in list(zip_longest(journals, taxes)):
                journal, tax = journal_and_tax
                worksheet.write(row, 7, journal.get('journalAccountCode'))
                worksheet.write(row, 8, journal.get('journalPayee'))
                worksheet.write(row, 9, journal.get('journalPayer'))
                worksheet.write(row, 11, tax.get('taxCode'))
                worksheet.write(row, 12, tax.get('taxSource'))

                # taxGuid details
                tax_guides = journal.get('taxGuid', [])
                if not tax_guides:
                    row = row + 1
                    continue

                for tax_guide in tax_guides:
                    worksheet.write(row, 10, tax_guide)
                    row = row + 1

# finally close the created excel file
workbook.close()

One thing, instead of creating a template in the script you can make your own one and save it somewhere else. Then get the copy of that template and just add data using the script. This will give you a chance to make your own base template, otherwise, you have to format your excel using the script, such as border formattings, merge cells, etc.

I used zip_longest python built-in function from itertools to zip journal and tax objects. Just follow Python – Itertools.zip_longest() or Python's zip_longest Function article for examples. If you didn't understand anything from my code, please comment below.