Converting Apache .htaccess to Nginx configuration is a first-pass translation problem, not a copy-paste problem. Apache reads .htaccess on every request through the directory tree, while Nginx reads one centralized configuration and applies it through server and location contexts. A converter that silently rewrites an entire .htaccess file can produce syntactically valid but semantically wrong directives, and a misbehaving redirect can take a public site offline. The htaccess to Nginx Converter limits itself to a narrow, documented subset of directives and reports the rest by line number so a human can finish the job. The output is a review-ready fragment, not a complete nginx.conf, and you still choose where each line belongs, back up the active file, and run nginx -t before any reload. This article walks through what the tool actually translates, how to use it safely, and the checks to run before pointing production traffic at the result.
What the htaccess to Nginx Converter Actually Translates
The tool operates on a deliberately narrow contract. It accepts one focused document-root .htaccess excerpt at a time and processes one bounded line at a time, ignoring RewriteEngine On, preserving comments, and only emitting directives it can stand behind. The supported rewrite form is a RewriteRule line that contains a pattern, a substitution and a bracketed flag list, and the automatic flag set is intentionally limited to L, R, R=301 and R=302. A permanent Apache redirect becomes the Nginx permanent flag, a temporary redirect becomes redirect, and an internal last rule becomes last. Patterns in a document-root .htaccess normally match a path after the directory prefix has been removed, so they commonly begin with a caret but no slash; Nginx rewrite patterns see a URI that begins with a slash, so the converter inserts that leading slash for the supported root-context pattern.
Three non-rewrite mappings are also supported. Options -Indexes becomes autoindex off;, a local ErrorDocument 404 path becomes error_page 404 with the same path, and a quoted X-Robots-Tag Header set value becomes an add_header line. Processing stays in the browser, and the input is not sent to Lizely, which keeps credentialed or staging-only configuration snippets from leaving your machine. Other status codes, external error documents, conditional headers, environment variables and directive containers require manual migration.
How to Convert htaccess to Nginx Safely
- Paste a focused document-root .htaccess excerpt into the converter. Keep the input small, scoped to a single virtual host or document root. The tool only translates the explicitly supported directive subset, and pasting the whole file makes warnings harder to triage.
- Review every emitted line and resolve each line-numbered warning manually. Cross-reference each flagged rule with the Apache mod_rewrite introduction and the Nginx rewrite module reference to confirm the intended behaviour before you port it. A warning is part of the result, not a bug.
- Merge the converted fragment into the correct Nginx context. Decide whether each line belongs in a server block or a specific location block, then place it accordingly. The fragment does not create an http, server or location block, choose a listen port, set server_name, configure TLS, locate a document root, preserve PHP routing, forward a proxy, or define logs.
- Back up the active configuration before touching it. Keep an open recovery session, version-control the file you are editing, and stage the change on a non-production host when practical.
- Run nginx -t and test representative requests against staging. Confirm the response Location header rather than relying on the browser address bar alone. Only reload Nginx once both the syntax check and the request tests pass.
What Gets Converted vs What Gets Flagged
The table below summarises the supported mappings and the cases that produce a warning instead of an emission. Anything conditional, unfamiliar or syntactically ambiguous is reported with its original line number for manual work, which is why a short, line-numbered warning is preferable to a guessed rewrite.
| Apache source | Nginx output | Why |
|---|---|---|
| RewriteRule ^old$ /new/ [R=301,L] | rewrite ^/old$ /new/ permanent; | Supported: permanent redirect with last, leading slash inserted |
| RewriteRule ^page$ /index.php [L] | rewrite ^/page$ /index.php last; | Supported: internal last rule |
| RewriteRule ^/api/(.*)$ /$1 [L] | rewrite ^/api/(.*)$ /$1 last; | Supported: pattern with leading slash preserved |
| Options -Indexes | autoindex off; | Supported: directory listing disabled |
| ErrorDocument 404 /404.html | error_page 404 /404.html; | Supported: local 404 document via nginx core error_page |
| Header set X-Robots-Tag "noindex" | add_header X-Robots-Tag "noindex"; | Supported: quoted X-Robots-Tag header |
| RewriteCond %{HTTPS} off followed by a rule | Warning only, no rule emitted | Conditions are never translated automatically |
| RewriteRule ^page$ /new/ [QSA,L] | Warning only, no rule emitted | Unknown flag QSA stops the rule |
| RewriteRule ^page$ - [F,L] | Warning only, no rule emitted | Dash target withheld; forbids unsafe emission |
RewriteCond lines are never translated automatically because their variables, captures, evaluation order and deployment context can change meaning. When a RewriteRule follows a condition, the tool suppresses the rule too, rather than emitting an unconditional redirect that could change traffic, create a loop or expose a route. Unknown flags such as QSA, END, F, G, B or NC stop conversion for that rule because their details cannot be erased safely. The Apache no-substitution target represented by a single dash is also withheld, because it often combines with flags that alter access or processing without changing the URI, and a literal dash is not a safe Nginx replacement.
Migration Pitfalls Worth Flagging Before Reload
Apache and Nginx use different request-processing models. Apache .htaccess is discovered through directories and may be disabled by AllowOverride; Nginx reads centralized configuration and chooses server and location contexts before rewrite processing. Even identical regular expressions can behave differently because the string being matched, escaping, query handling and loop behavior differ. Read both official manuals for every nontrivial rule, and treat anything involving authentication, authorization, hotlink protection, proxy logic, CMS front-controller rules or complex conditions as engineering work rather than bulk text replacement. For a narrative walkthrough of the same workflow applied to a real excerpt, see the companion guide Convert Apache .htaccess to Nginx Rules Without Guesswork.
Permanent redirects deserve extra care because browsers and intermediaries may cache them. Start with temporary redirects in a controlled environment when practical, then switch to permanent only after testing old paths, new paths, query strings, alternate hosts and HTTPS behavior. Confirm the response Location header rather than relying on the browser address bar alone. A line can be syntactically valid yet wrong for its context, and a converter that silently writes plausible-looking but non-equivalent configuration is more dangerous than one that leaves explicit work.
Pre-Reload Checklist for a Safe Cutover
- Back up the current nginx.conf and any included files, and confirm the backup is restorable from your shell.
- Confirm every warning from the converter has been resolved or knowingly deferred, and document each manual change.
- Run nginx -t against the assembled file. A passing test is necessary but not sufficient.
- Test representative requests against staging, including old paths, new paths, query strings, alternate hosts and HTTPS behaviour.
- Confirm the response Location header for redirects with curl -I or a header inspection tool, not just the browser address bar.
- Stage the change during a reversible maintenance window, with a session ready to revert the configuration if the first reload misbehaves.
- Keep a copy of the original .htaccess for comparison, and store the new Nginx configuration in version control.
Treat the converter as an inventory assistant: paste one focused excerpt, review the converted count, resolve every warning, assemble the result in a version-controlled Nginx file and validate it on staging before reloading. If your source contains authentication, authorization, hotlink protection, proxy logic, CMS front-controller rules or complex conditions, treat the migration as engineering work rather than bulk text replacement.