Legacy ASP.NET Website Migration
How to move an older ASP.NET or database-driven site into a simpler architecture without carrying forward obsolete configuration and server dependencies.
Treat the server configuration as evidence, not instructions
Legacy ASP.NET sites often contain web.config rules, machine-specific temporary paths, assembly references, database strings and handlers that were valid on an older Windows hosting environment. Copying those files into a new static deployment can create 500 errors or expose unnecessary secrets.
Read them to understand how the old site worked, then rebuild only the behaviour you still need.
Find dynamic routes before removing the database
Pages may be generated from query strings, numeric IDs or routing rules. Crawl internal links and search for database-backed content lists so you can map those outputs to permanent HTML files before the application layer disappears.
Preserve forms and business actions
A static rebuild can remove ASP.NET page rendering while keeping contact, quote or booking actions through a separate endpoint. Test these workflows independently. A visually complete migration is not complete if the lead form silently stopped working.
Delete obsolete server files only after archive
Archive bin folders, configuration, database files and code-behind sources offline. Then keep them off the public static site unless there is a documented reason. This reduces deployment confusion and avoids old application code continuing to execute unexpectedly.
Validate IIS behaviour
On Windows hosting, confirm default documents, MIME types, redirect behaviour and error pages. A static package should not assume the same module set or application pool configuration as the legacy ASP.NET site it replaces.
Map application-generated URLs
Older ASP.NET sites may use default.aspx routes, query strings, postbacks or URL-rewriting modules. Create a list of public-facing routes before the application is removed, including routes that are not represented by physical files on disk.
Keep secrets out of the static package
Connection strings, SMTP credentials, machine keys and API tokens belong in secure configuration—not inside an archive that will be uploaded publicly. A migration is a good opportunity to rotate exposed credentials and remove them from the web root entirely.