Error Logs - Log Read

Endpoint

/o/errorlogs

Overview

Returns one selected Countly log file, either as text response or as downloadable attachment.

Authentication

Pass api_key or auth_token as a query parameter, or send countly-token as a header. See Authentication.

Permissions

• Required permission: Global Admin.

Request Parameters

Parameter	Type	Required	Description
api_key	String	Yes (or use auth_token)	API key for authentication.
auth_token	String	No	Auth token as query parameter or countly-token header.
log	String	No	Log key to read (for example api, dashboard, or discovered countly-*.log key). If omitted or invalid, endpoint returns all logs map.
bytes	Number	No	If greater than 0, returns only the last N bytes (aligned to first full line in the read chunk).
download	Boolean/String	No	When truthy, returns raw text as attachment instead of JSON string response.

Examples

Read API log as text

/o/errorlogs?api_key=YOUR_API_KEY&log=api

Download last 5000 bytes of dashboard log

/o/errorlogs?api_key=YOUR_API_KEY&log=dashboard&bytes=5000&download=true

Response

Success Response

Text mode (default):

"2026-02-17 10:00:00 [INFO] API started\n2026-02-17 10:01:12 [WARN] Slow query"

Download mode (download=true):

Content-Type: plain/text; charset=utf-8
Content-Disposition: attachment; filename=countly-api.log

2026-02-17 10:00:00 [INFO] API started
2026-02-17 10:01:12 [WARN] Slow query

Response Fields

Field	Type	Description
(root)	String	Log text when not downloading.

Error Responses

• 400

{
  "result": "Missing parameter \"api_key\" or \"auth_token\""
}

• 400

{
  "result": "Token not valid"
}

• 401

{
  "result": "User does not exist"
}

• 401

{
  "result": "User does not have right"
}

• 401

{
  "result": "User is locked"
}

• 401

{
  "result": "Token is invalid"
}

Behavior

Behavior Modes

Mode	Trigger	Processing Path	Response Shape
Text mode	download not provided/false	Reads full/tail file content and returns via JSON output helper.	Raw root string log text.
Download mode	download=true	Reads full/tail file content and returns raw body with attachment headers.	Raw text attachment payload.
Fallback mode	log missing or unknown key	Falls back to all-log map behavior from /o/errorlogs.	Raw root object (log_key -> log_text).

Limitations

• If file read fails, the endpoint returns empty string for that log content.
• download mode changes response from JSON string to raw attachment output.

Related Endpoints

• Error Logs - Logs Read
• Error Logs - Log Clear

Implementation details

Database Collections

This endpoint does not read or write database collections.