How to Convert an Outlook PST to JSON for Scripts and Analysis

PST is one of the gnarliest file formats around: a binary database with its own B-tree structures. Parsing it yourself means finding a library for your language and hoping it handles Unicode and odd edge cases. If you just need the data, JSON is quicker.

The output

An array with one object per email:

{
  "folder": "Inbox/Suppliers",
  "subject": "Re: Pricing for Q3",
  "from": [{ "name": "Jordan Reyes", "address": "jordan@supplier.com" }],
  "to": [{ "name": "Sam Lee", "address": "sam@example.com" }],
  "cc": [],
  "date": "2023-05-09T09:02:00.000Z",
  "text": "Happy to confirm the 8% discount…",
  "html": null,
  "attachments": [{ "name": "price-list.xlsx", "type": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", "size": 49152 }]
}

• text is always filled in, converted from HTML when that's all there is.
• html is null for plain-text emails.
• Attachment contents aren't included, only their metadata.

How to convert PST to JSON with ZapMorph

1. Open the converter

Go to the PST to JSON converter.

2. Add your PST

Drop in the .pst file.

3. Convert and download

Click Convert to JSON.

Example: emails per folder

const emails = JSON.parse(await fs.readFile('archive.json', 'utf8'));
const perFolder = Object.groupBy(emails, (e) => e.folder ?? 'unknown');
console.table(Object.fromEntries(Object.entries(perFolder).map(([k, v]) => [k, v.length])));

Example: load into pandas

import pandas as pd

df = pd.read_json("archive.json")
df["date"] = pd.to_datetime(df["date"])
df["sender"] = df["from"].map(lambda f: f[0]["address"] if f else None)
print(df.groupby(df["date"].dt.year).size())        # emails per year
print(df["sender"].value_counts().head(10))          # top senders

Example: jq one-liners

jq 'length' archive.json                                       # total emails
jq '[.[] | select(.attachments | length > 0)] | length' archive.json  # with attachments
jq -r '.[] | select(.subject | test("invoice"; "i")) | .date + "  " + .subject' archive.json

Ideas

• eDiscovery: filter by custodian, date range and keywords, then export matches with PST to PDF.
• CRM import: map senders and dates into contact activity history.
• Search index: load text into Elasticsearch, SQLite FTS or a vector database.

Related

• PST analyzer for counts without writing code.
• PST to CSV for a spreadsheet.
• JSON viewer to browse the result.

Summary

The PST to JSON converter gives you an Outlook archive as clean JSON, folder names included, without touching a PST library.