Does this work as an Apache log viewer?

Yes. Apache Combined Log Format, Common Log Format, and Combined with a virtual host are all auto-detected line by line - paste a raw Apache log and it parses without you declaring the format.

Can I use it as an Nginx log viewer?

Yes, Nginx access logs are detected and parsed the same way as Apache logs, in the same file if you have mixed sources - no separate mode to switch.

Does it read ISA Server or Forefront TMG proxy logs?

Yes. Microsoft ISA and Forefront TMG proxy logs parse alongside web server logs, so you can analyze what came through the proxy in the same view as your Apache or Nginx traffic.

Is this a log viewer I can use online without installing anything?

Yes. It runs entirely in your browser - no install, no account, no upload. Paste or load a file and the parsing happens locally.

What can an access log analysis with this tool actually show me?

Top IPs, user agents, and requested URLs by count - which is usually how you find the crawler or bot nobody knew was hitting the site - plus status-code patterns across whatever slice you filter to.

Can it read error logs too?

No - this viewer is for access logs, one line per request: who asked for which URL and which status they got. PHP and Apache error logs, with stack traces and warnings that repeat on every request, belong in the error log viewer listed under related tools.

Cost: Free
Sign-up: None
Runs: In your browser

Access log viewer

Paste a raw Apache, Nginx, IIS, ISA or proxy access log and read what actually hit your server - crawler behaviour, status-code patterns, and the requests nobody is looking at.

What it does

5 capabilities

Format detection: Apache Combined, Apache Common, Combined with virtual host, Nginx, IIS and custom patterns - detected and parsed without you declaring which you have.
Filtering: Narrow by IP, status code, URL or date with debounced search, so a large file stays responsive while you are still deciding what you are looking for.
Analytics: Top IPs, user agents and requested URLs, surfaced as counts - which is usually how you find the bot nobody knew was crawling you.
Proxy and ISA logs: Proxy access logs - including Microsoft ISA and Forefront TMG - parse alongside web server logs, so you can analyse what came through the proxy in the same place.
Export: Take the filtered set out as a clean file for whatever you were going to do with it next.

How it runs

Step 1
Load a .log, .txt or .json access log from your machine. It is read locally and never sent anywhere.
Step 2
Filter and search until you have the slice you care about, then read the analytics in the sidebar.
Step 3
Export the filtered rows, or close the tab and leave nothing behind.

Accepted input

Apache

Combined Log Format
Common Log Format
Combined with virtual host
Custom Apache patterns

Other servers and proxies

Nginx access logs
IIS log formats
Microsoft ISA / Forefront TMG proxy logs
Squid and generic proxy logs
JSON logs, including Splunk JSON
JSON Lines
Custom delimited formats

How to read an access log

One line, one request

66.249.66.1 - - [12/Oct/2026:06:25:14 +0200] "GET /blog/prestashop-seo-guide-2026 HTTP/1.1" 200 48211 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)"

That is one request in Apache Combined Log Format. Left to right: the client IP, identity and user (almost always dashes), the timestamp, the request line (method, path, protocol), the status code, the response size in bytes, the referer and the user agent.

Common Log Format is the same line without the last two fields - which is why a Common log cannot tell you who the visitor claimed to be or where they came from.

Apache, Nginx and IIS: same data, different layout

Nginx's default combined format writes the same fields in the same order as Apache, so most Nginx access logs read exactly like the line above.

IIS writes W3C extended logs: space-separated fields declared in a #Fields: header at the top of the file, with date and time in separate columns and timestamps in UTC. ISA Server and Forefront TMG proxy logs use a similar W3C layout, but they record what your users requested from the outside world, not what the world requested from your server.

The viewer detects the format line by line, so a file that mixes sources still parses without you choosing a mode.

What to look for first

Status codes. A growing share of 404s points at broken internal links or old URLs that lost their redirect. 5xx responses, even a few an hour, mean visitors and crawlers are hitting failures you never see in your own browser. A redirect shows up as a 301 or 302 followed by a second request for the target - two hops in a row is a chain worth flattening.

User agents. Sort by count and the top entries are rarely people: search engine crawlers, SEO tools, uptime monitors and scrapers. An unfamiliar agent requesting thousands of URLs is worth a closer look.

Requested URLs. If the most-requested paths are filter combinations, internal search results or session parameters rather than your products and articles, crawlers are spending their time on pages you never wanted indexed.

Access log analysis for SEO

Search Console shows a sample of crawl activity; the access log shows every request. Filter the user agent to Googlebot and you see which sections it visits, how often, and which status it gets back - the most direct evidence there is of crawl budget going to parameter URLs, redirect chains, or pages that fail only for bots.

Anyone can send a Googlebot user agent, so verify the IPs that matter with a reverse DNS lookup: genuine Googlebot resolves to a googlebot.com or google.com hostname, and a forward lookup of that hostname returns the same IP.

When a viewer is the right tool

grep and awk answer a question you already know how to ask. A viewer is for the first pass over an unfamiliar log, when you do not yet know what the question is. For continuous monitoring across many servers, a pipeline on the server - GoAccess, or an ELK stack - is the better fit. This is for the file you were just handed.

FAQ

Does this work as an Apache log viewer?: Yes. Apache Combined Log Format, Common Log Format, and Combined with a virtual host are all auto-detected line by line - paste a raw Apache log and it parses without you declaring the format.
Can I use it as an Nginx log viewer?: Yes, Nginx access logs are detected and parsed the same way as Apache logs, in the same file if you have mixed sources - no separate mode to switch.
Does it read ISA Server or Forefront TMG proxy logs?: Yes. Microsoft ISA and Forefront TMG proxy logs parse alongside web server logs, so you can analyze what came through the proxy in the same view as your Apache or Nginx traffic.
Is this a log viewer I can use online without installing anything?: Yes. It runs entirely in your browser - no install, no account, no upload. Paste or load a file and the parsing happens locally.
What can an access log analysis with this tool actually show me?: Top IPs, user agents, and requested URLs by count - which is usually how you find the crawler or bot nobody knew was hitting the site - plus status-code patterns across whatever slice you filter to.
Can it read error logs too?: No - this viewer is for access logs, one line per request: who asked for which URL and which status they got. PHP and Apache error logs, with stack traces and warnings that repeat on every request, belong in the error log viewer listed under related tools.

Nothing is uploaded. Nothing is stored.

It runs entirely in your browser, with no account and no server round-trip. Close the tab and it is gone.

Related tools

Error log viewerTurn a server error log into something legible: grouped traces, repeat offenders, and the errors quietly firing on every single request.
SEO analyzerPoint it at a URL and get the technical picture: what renders server-side, what the metadata claims, and what a crawler actually comes away with.

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MaintenanceShopify maintenance: a developer who knows your theme, on hand after launch.