File Format (.pro)

A .pro file is a JSON-encoded snapshot of captured traffic. Probe writes it when you save a session (Cmd+S on a recording tab) or export entries via the right-click menu. The same file shape was previously called .gmp (“Guide MITM Proxy”); both extensions are still accepted on import.

Probe also writes two related shapes — collection exports for a multi-entry export and request exports for a single entry. The importer routes by the JSON format field, not the file extension.

Top-level shape

The first key tells the importer what’s inside:

{
  "format": "guide-session" | "guide-collection" | "guide-request",
  "version": 1,
  ...
}

Probe trusts the format value over the extension — you can rename a file from .json to .pro (or vice-versa) and import will still work.

guide-session

The full snapshot a saved tab produces. Lives in ~/.probe/sessions/<id>.json for the in-app sessions list; written to a user-chosen path on Save Session….

{
  "format": "guide-session",
  "version": 1,
  "id": "01HXY7M0QZJ8R5ZF6Q4Y8MR8GA",
  "name": "Auth flow — staging",
  "createdAt": 1731081900123,
  "entries": [
    { /* LogEntry */ },
    { /* LogEntry */ }
  ]
}

Field	Type	Description
`format`	string	Must be `"guide-session"`.
`version`	integer	`1` today. Bumped on a breaking format change.
`id`	string	Session id (ULID-style).
`name`	string	Display name. Editable via the Sessions manager.
`createdAt`	integer	Milliseconds since epoch, UTC.
`entries`	array	One `LogEntry` per captured request.

guide-collection

The export format for a multi-entry export (right-click on selected rows → Export).

{
  "format": "guide-collection",
  "version": 1,
  "exportedAt": 1731082000000,
  "entries": [ /* LogEntry, ... */ ]
}

Same entries shape as a session, without the session-level id and name. On import, each entry is added to the active recording tab.

guide-request

A single-entry export. Useful for sharing one request without surrounding noise.

{
  "format": "guide-request",
  "version": 1,
  "entry": { /* LogEntry */ }
}

LogEntry shape

The same LogEntry JSON appears inside every Guide format above:

{
  "id": 142,
  "method": "POST",
  "url": "https://api.example.com/v1/users",
  "statusCode": 201,
  "timestamp": 1731081900123,
  "clientAddr": "Chrome",
  "reqHeaders": {
    "content-type": "application/json",
    "authorization": "Bearer ..."
  },
  "reqBody": "{\"name\":\"Ada\"}",
  "resHeaders": {
    "content-type": "application/json",
    "content-length": "21"
  },
  "resBody": "{\"id\":1,\"name\":\"Ada\"}",
  "contentType": "application/json",
  "durationMs": 184,
  "reqSize": 124,
  "resSize": 21
}

Field	Type	Notes
`id`	integer	Unique per session.
`method`	string	HTTP method.
`url`	string	Full URL the client sent. MITM-intercepted entries carry the explicit `:443`/`:80` port.
`statusCode`	integer	`0` if no response was received (request errored mid-flight or was aborted).
`timestamp`	integer	Milliseconds since epoch, UTC.
`clientAddr`	string	Process name for loopback traffic, IP address for remote phones. May be empty.
`reqHeaders`	object	Lower-cased keys, single value per key.
`reqBody`	string \| null	Raw body as text. Bodies above the size cap or non-text content show as `"[binary or oversized body]"`.
`resHeaders`	object	Same conventions as `reqHeaders`.
`resBody`	string \| null	Same conventions as `reqBody`.
`contentType`	string \| null	Sniffed from the response.
`durationMs`	integer \| null	Total request → response time.
`reqSize`	integer	Bytes-on-the-wire estimate of the request.
`resSize`	integer	Bytes-on-the-wire estimate of the response.

Fields not in the JSON are tolerated by LogEntry.fromJson — defaults are applied (statusCode = 0, empty headers, etc.). That makes forward-compatibility easy: a future version that adds new fields can be loaded by an older Probe.

Compatibility

.gmp files — same JSON shape, accepted by every importer. Probe writes .pro for new exports.
.json files — accepted; the importer sniffs format.
Renamed extensions — fine. Content-sniffing wins over the extension.

What’s NOT in the file

No request/response that was already discarded for size — bodies stripped at capture time stay stripped. Sessions are wire-level, not browser-level.
No HAR support today. Probe doesn’t read or write HAR.
No environment data, scripts, breakpoints, or rules. A .pro only carries traffic. Compose collections (with environments and scripts) live separately under ~/.probe/compose/<collection-id>.json.