Environment variables

All configuration is by environment variable; there is no config file.

Variable	Required	Type	Default	Description
LINKWARDEN_URL	yes	string	—	Base URL, e.g. https://links.example.net. Without /api/v1.
LINKWARDEN_TOKEN	yes	secret	—	Access token from Settings → Access Tokens.
LINKWARDEN_READ_ONLY	no	boolean	false	true registers only the 11 read tools.
LINKWARDEN_INSECURE_TLS	no	boolean	false	true accepts self-signed certificates, scoped to this connection.

Booleans are compared against the literal string true. True, 1 and yes are off, so a typo fails closed rather than silently disabling certificate validation.

Validation at startup

LINKWARDEN_URL is parsed with new URL. The server exits when it:

• does not parse,
• uses a scheme other than http: or https:,
• contains credentials (https://user:pw@host).

It warns and continues when:

• the URL is plain http: to a non-loopback host (the token would be sent in clear),
• LINKWARDEN_TOKEN does not start with ey (Linkwarden tokens are NextAuth JWTs, so this usually means a cookie or password was pasted in),
• either required variable is missing — the server still starts and lists its tools so registries and inspectors can introspect it; every call then fails with setup instructions.

Normalisation: a trailing slash is stripped, and a /api/v1 suffix is removed, since the client appends the prefix itself and redirects are never followed.

Token handling

LINKWARDEN_TOKEN is deleted from the process environment as soon as it is read — before any branch of the parser, including the ones that exit — so it is not visible to child processes or in /proc/<pid>/environ. It is never logged and never appears in an error message.

Not environment variables

There are no variables for timeouts, page sizes or result budgets; those are fixed:

Limit	Value
Request timeout	30 s
Response body ceiling	8 MB
Result budget	200 000 characters
Links per search	100
Links per bulk operation	200
Article slice, default	20 000 characters
Confirmation token TTL	5 minutes