diff --git a/changelog.d/14744.doc b/changelog.d/14744.doc
new file mode 100644
index 0000000000..738ab1a46d
--- /dev/null
+++ b/changelog.d/14744.doc
@@ -0,0 +1 @@
+Fix broken links in the Synapse documentation.
\ No newline at end of file
diff --git a/docs/admin_api/account_validity.md b/docs/admin_api/account_validity.md
index d878bf7451..87d8f7150e 100644
--- a/docs/admin_api/account_validity.md
+++ b/docs/admin_api/account_validity.md
@@ -5,7 +5,7 @@ use it, you must enable the account validity feature (under
 `account_validity`) in Synapse's configuration.
 
 To use it, you will need to authenticate by providing an `access_token`
-for a server admin: see [Admin API](../usage/administration/admin_api).
+for a server admin: see [Admin API](../usage/administration/admin_api/).
 
 ## Renew account
 
diff --git a/docs/admin_api/event_reports.md b/docs/admin_api/event_reports.md
index be6f0961bf..beec8bb7ef 100644
--- a/docs/admin_api/event_reports.md
+++ b/docs/admin_api/event_reports.md
@@ -3,7 +3,7 @@
 This API returns information about reported events.
 
 To use it, you will need to authenticate by providing an `access_token`
-for a server admin: see [Admin API](../usage/administration/admin_api).
+for a server admin: see [Admin API](../usage/administration/admin_api/).
 
 The api is:
 ```
diff --git a/docs/admin_api/media_admin_api.md b/docs/admin_api/media_admin_api.md
index d57c5aedae..7f8c8e22c1 100644
--- a/docs/admin_api/media_admin_api.md
+++ b/docs/admin_api/media_admin_api.md
@@ -6,7 +6,7 @@ Details about the format of the `media_id` and storage of the media in the file
 are documented under [media repository](../media_repository.md).
 
 To use it, you will need to authenticate by providing an `access_token`
-for a server admin: see [Admin API](../usage/administration/admin_api).
+for a server admin: see [Admin API](../usage/administration/admin_api/).
 
 ## List all media in a room
 
diff --git a/docs/admin_api/purge_history_api.md b/docs/admin_api/purge_history_api.md
index 2527e2758b..ba6d08aa4d 100644
--- a/docs/admin_api/purge_history_api.md
+++ b/docs/admin_api/purge_history_api.md
@@ -11,7 +11,7 @@ Note that Synapse requires at least one message in each room, so it will never
 delete the last message in a room.
 
 To use it, you will need to authenticate by providing an `access_token`
-for a server admin: see [Admin API](../usage/administration/admin_api).
+for a server admin: see [Admin API](../usage/administration/admin_api/).
 
 The API is:
 
diff --git a/docs/admin_api/room_membership.md b/docs/admin_api/room_membership.md
index 310d6ae628..94bc95a8d5 100644
--- a/docs/admin_api/room_membership.md
+++ b/docs/admin_api/room_membership.md
@@ -6,7 +6,7 @@ local users. The server administrator must be in the room and have permission to
 invite users.
 
 To use it, you will need to authenticate by providing an `access_token`
-for a server admin: see [Admin API](../usage/administration/admin_api).
+for a server admin: see [Admin API](../usage/administration/admin_api/).
 
 ## Parameters
 
diff --git a/docs/admin_api/rooms.md b/docs/admin_api/rooms.md
index 8f727b363e..66b29e82dc 100644
--- a/docs/admin_api/rooms.md
+++ b/docs/admin_api/rooms.md
@@ -5,7 +5,7 @@ server. There are various parameters available that allow for filtering and
 sorting the returned list. This API supports pagination.
 
 To use it, you will need to authenticate by providing an `access_token`
-for a server admin: see [Admin API](../usage/administration/admin_api).
+for a server admin: see [Admin API](../usage/administration/admin_api/).
 
 **Parameters**
 
@@ -400,7 +400,7 @@ sent to a room in a given timeframe. There are various parameters available
 that allow for filtering and ordering the returned list. This API supports pagination.
 
 To use it, you will need to authenticate by providing an `access_token`
-for a server admin: see [Admin API](../usage/administration/admin_api).
+for a server admin: see [Admin API](../usage/administration/admin_api/).
 
 This endpoint mirrors the [Matrix Spec defined Messages API](https://spec.matrix.org/v1.1/client-server-api/#get_matrixclientv3roomsroomidmessages).
 
diff --git a/docs/admin_api/statistics.md b/docs/admin_api/statistics.md
index a26c76f9f3..03b3621e55 100644
--- a/docs/admin_api/statistics.md
+++ b/docs/admin_api/statistics.md
@@ -4,7 +4,7 @@ Returns information about all local media usage of users. Gives the
 possibility to filter them by time and user.
 
 To use it, you will need to authenticate by providing an `access_token`
-for a server admin: see [Admin API](../usage/administration/admin_api).
+for a server admin: see [Admin API](../usage/administration/admin_api/).
 
 The API is:
 
diff --git a/docs/admin_api/user_admin_api.md b/docs/admin_api/user_admin_api.md
index 880bef4194..86c29ab380 100644
--- a/docs/admin_api/user_admin_api.md
+++ b/docs/admin_api/user_admin_api.md
@@ -1,7 +1,7 @@
 # User Admin API
 
 To use it, you will need to authenticate by providing an `access_token`
-for a server admin: see [Admin API](../usage/administration/admin_api).
+for a server admin: see [Admin API](../usage/administration/admin_api/).
 
 ## Query User Account
 
diff --git a/docs/development/contributing_guide.md b/docs/development/contributing_guide.md
index d07790f184..43cb3e201d 100644
--- a/docs/development/contributing_guide.md
+++ b/docs/development/contributing_guide.md
@@ -106,8 +106,8 @@ regarding Synapse's Admin API, which is used mostly by sysadmins and external
 service developers.
 
 Synapse's code style is documented [here](../code_style.md). Please follow
-it, including the conventions for the [sample configuration
-file](../code_style.md#configuration-file-format).
+it, including the conventions for [configuration
+options and documentation](../code_style.md#configuration-code-and-documentation-format).
 
 We welcome improvements and additions to our documentation itself! When
 writing new pages, please
@@ -126,7 +126,7 @@ changes to the Rust code.
 
 
 # 8. Test, test, test!
-<a name="test-test-test"></a>
+<a name="test-test-test" id="test-test-test"></a>
 
 While you're developing and before submitting a patch, you'll
 want to test your code.
@@ -424,8 +424,7 @@ chicken-and-egg problem.
 There are two options for solving this:
 
 1. Open the PR without a changelog file, see what number you got, and *then*
-   add the changelog file to your branch (see [Updating your pull
-   request](#updating-your-pull-request)), or:
+   add the changelog file to your branch, or:
 
 1. Look at the [list of all
    issues/PRs](https://github.com/matrix-org/synapse/issues?q=), add one to the
diff --git a/docs/modules/writing_a_module.md b/docs/modules/writing_a_module.md
index e6303b739e..30de69a533 100644
--- a/docs/modules/writing_a_module.md
+++ b/docs/modules/writing_a_module.md
@@ -59,8 +59,8 @@ namespace (such as anything under `/_matrix/client` for example). It is strongly
 recommended that modules register their web resources under the `/_synapse/client`
 namespace.
 
-The provided resource is a Python class that implements Twisted's [IResource](https://twistedmatrix.com/documents/current/api/twisted.web.resource.IResource.html)
-interface (such as [Resource](https://twistedmatrix.com/documents/current/api/twisted.web.resource.Resource.html)).
+The provided resource is a Python class that implements Twisted's [IResource](https://docs.twistedmatrix.com/en/stable/api/twisted.web.resource.IResource.html)
+interface (such as [Resource](https://docs.twistedmatrix.com/en/stable/api/twisted.web.resource.Resource.html)).
 
 Only one resource can be registered for a given path. If several modules attempt to
 register a resource for the same path, the module that appears first in Synapse's
@@ -82,4 +82,4 @@ the callback name as the argument name and the function as its value. A
 `register_[...]_callbacks` method exists for each category.
 
 Callbacks for each category can be found on their respective page of the
-[Synapse documentation website](https://matrix-org.github.io/synapse).
\ No newline at end of file
+[Synapse documentation website](https://matrix-org.github.io/synapse).
diff --git a/docs/openid.md b/docs/openid.md
index 45aa24dd24..6ee8c83ec0 100644
--- a/docs/openid.md
+++ b/docs/openid.md
@@ -463,7 +463,7 @@ oidc_providers:
 Keycloak supports OIDC Back-Channel Logout, which sends logout notification to Synapse, so that Synapse users get logged out when they log out from Keycloak.
 This can be optionally enabled by setting `backchannel_logout_enabled` to `true` in the Synapse configuration, and by setting the "Backchannel Logout URL" in Keycloak.
 
-Follow the [Getting Started Guide](https://www.keycloak.org/getting-started) to install Keycloak and set up a realm.
+Follow the [Getting Started Guide](https://www.keycloak.org/guides) to install Keycloak and set up a realm.
 
 1. Click `Clients` in the sidebar and click `Create`
 
diff --git a/docs/postgres.md b/docs/postgres.md
index 46b4603fe5..fba4430f33 100644
--- a/docs/postgres.md
+++ b/docs/postgres.md
@@ -16,7 +16,7 @@ connect to a postgres database.
 -   For other pre-built packages, please consult the documentation from
     the relevant package.
 -   If you installed synapse [in a
-    virtualenv](setup/installation.md#installing-from-source), you can install
+    virtualenv](setup/installation.md#installing-as-a-python-module-from-pypi), you can install
     the library with:
 
         ~/synapse/env/bin/pip install "matrix-synapse[postgres]"
diff --git a/docs/setup/installation.md b/docs/setup/installation.md
index a762ad55df..d123e339ed 100644
--- a/docs/setup/installation.md
+++ b/docs/setup/installation.md
@@ -136,7 +136,7 @@ Unofficial package are built for SLES 15 in the openSUSE:Backports:SLE-15 reposi
 #### ArchLinux
 
 The quickest way to get up and running with ArchLinux is probably with the community package
-<https://www.archlinux.org/packages/community/any/matrix-synapse/>, which should pull in most of
+<https://archlinux.org/packages/community/x86_64/matrix-synapse/>, which should pull in most of
 the necessary dependencies.
 
 pip may be outdated (6.0.7-1 and needs to be upgraded to 6.0.8-1 ):
diff --git a/docs/sso_mapping_providers.md b/docs/sso_mapping_providers.md
index 9f5e5fbbe1..a5d4659619 100644
--- a/docs/sso_mapping_providers.md
+++ b/docs/sso_mapping_providers.md
@@ -120,7 +120,7 @@ specified in the config. It is located at
 ## SAML Mapping Providers
 
 The SAML mapping provider can be customized by editing the
-[`saml2_config.user_mapping_provider.module`](docs/usage/configuration/config_documentation.md#saml2_config)
+[`saml2_config.user_mapping_provider.module`](usage/configuration/config_documentation.md#saml2_config)
 config option.
 
 `saml2_config.user_mapping_provider.config` allows you to provide custom
diff --git a/docs/upgrade.md b/docs/upgrade.md
index dcae12ec94..f853dfdb8e 100644
--- a/docs/upgrade.md
+++ b/docs/upgrade.md
@@ -889,8 +889,8 @@ Any scripts still using the above APIs should be converted to use the
 ## User-interactive authentication fallback templates can now display errors
 
 This may affect you if you make use of custom HTML templates for the
-[reCAPTCHA](../synapse/res/templates/recaptcha.html) or
-[terms](../synapse/res/templates/terms.html) fallback pages.
+[reCAPTCHA (`synapse/res/templates/recaptcha.html`)](https://github.com/matrix-org/synapse/tree/develop/synapse/res/templates/recaptcha.html) or
+[terms (`synapse/res/templates/terms.html`)](https://github.com/matrix-org/synapse/tree/develop/synapse/res/templates/terms.html) fallback pages.
 
 The template is now provided an `error` variable if the authentication
 process failed. See the default templates linked above for an example.
@@ -1488,7 +1488,7 @@ New templates (`sso_auth_confirm.html`, `sso_auth_success.html`, and
 is configured to use SSO and a custom
 `sso_redirect_confirm_template_dir` configuration then these templates
 will need to be copied from
-[synapse/res/templates](synapse/res/templates) into that directory.
+[`synapse/res/templates`](https://github.com/matrix-org/synapse/tree/develop/synapse/res/templates) into that directory.
 
 ## Synapse SSO Plugins Method Deprecation
 
diff --git a/docs/usage/administration/admin_api/README.md b/docs/usage/administration/admin_api/README.md
index c00de2dd44..7c85bf751b 100644
--- a/docs/usage/administration/admin_api/README.md
+++ b/docs/usage/administration/admin_api/README.md
@@ -7,7 +7,7 @@ server admin. (Note that a server admin is distinct from a room admin.)
 
 An existing user can be marked as a server admin by updating the database directly.
 
-Check your [database settings](config_documentation.md#database) in the configuration file, connect to the correct database using either `psql [database name]` (if using PostgreSQL) or `sqlite3 path/to/your/database.db` (if using SQLite) and elevate the user `@foo:bar.com` to administrator.
+Check your [database settings](../../configuration/config_documentation.md#database) in the configuration file, connect to the correct database using either `psql [database name]` (if using PostgreSQL) or `sqlite3 path/to/your/database.db` (if using SQLite) and elevate the user `@foo:bar.com` to administrator.
 ```sql
 UPDATE users SET admin = 1 WHERE name = '@foo:bar.com';
 ```
@@ -32,10 +32,10 @@ curl --header "Authorization: Bearer <access_token>" <the_rest_of_your_API_reque
 ```
 
 For example, suppose we want to
-[query the account](user_admin_api.md#query-user-account) of the user
+[query the account](../../../admin_api/user_admin_api.md#query-user-account) of the user
 `@foo:bar.com`. We need an admin access token (e.g.
 `syt_AjfVef2_L33JNpafeif_0feKJfeaf0CQpoZk`), and we need to know which port
-Synapse's [`client` listener](config_documentation.md#listeners) is listening
+Synapse's [`client` listener](../../configuration/config_documentation.md#listeners) is listening
 on (e.g. `8008`). Then we can use the following command to request the account
 information from the Admin API.
 
diff --git a/docs/usage/administration/admin_api/federation.md b/docs/usage/administration/admin_api/federation.md
index 60cbc5265e..51f3b52da8 100644
--- a/docs/usage/administration/admin_api/federation.md
+++ b/docs/usage/administration/admin_api/federation.md
@@ -81,7 +81,7 @@ The following fields are returned in the JSON response body:
   - `failure_ts` - nullable integer - The first time Synapse tried and failed to reach the
     remote server, in ms. This is `null` if communication with the remote server has never failed.
   - `last_successful_stream_ordering` - nullable integer - The stream ordering of the most
-    recent successfully-sent [PDU](understanding_synapse_through_grafana_graphs.md#federation)
+    recent successfully-sent [PDU](../understanding_synapse_through_grafana_graphs.md#federation)
     to this destination, or `null` if this information has not been tracked yet.
 - `next_token`: string representing a positive integer - Indication for pagination. See above.
 - `total` - integer - Total number of destinations.
@@ -174,7 +174,7 @@ The following fields are returned in the JSON response body:
   Room objects contain the following fields:
   - `room_id` - string - The ID of the room.
   - `stream_ordering` - integer -  The stream ordering of the most recent
-    successfully-sent [PDU](understanding_synapse_through_grafana_graphs.md#federation)
+    successfully-sent [PDU](../understanding_synapse_through_grafana_graphs.md#federation)
     to this destination in this room.
 - `next_token`: string representing a positive integer - Indication for pagination. See above.
 - `total` - integer - Total number of destinations.
diff --git a/docs/usage/administration/admin_api/registration_tokens.md b/docs/usage/administration/admin_api/registration_tokens.md
index 90cbc21125..c5130859d4 100644
--- a/docs/usage/administration/admin_api/registration_tokens.md
+++ b/docs/usage/administration/admin_api/registration_tokens.md
@@ -6,7 +6,7 @@ registration requests, as proposed in
 and stabilised in version 1.2 of the Matrix specification.
 To use it, you will need to enable the `registration_requires_token` config
 option, and authenticate by providing an `access_token` for a server admin:
-see [Admin API](../admin_api).
+see [Admin API](../admin_api/).
 
 
 ## Registration token objects
diff --git a/docs/usage/administration/admin_faq.md b/docs/usage/administration/admin_faq.md
index 0bfb732464..a6dc6197c9 100644
--- a/docs/usage/administration/admin_faq.md
+++ b/docs/usage/administration/admin_faq.md
@@ -2,7 +2,7 @@
 
 How do I become a server admin?
 ---
-If your server already has an admin account you should use the [User Admin API](../../admin_api/user_admin_api.md#Change-whether-a-user-is-a-server-administrator-or-not) to promote other accounts to become admins.
+If your server already has an admin account you should use the [User Admin API](../../admin_api/user_admin_api.md#change-whether-a-user-is-a-server-administrator-or-not) to promote other accounts to become admins.
 
 If you don't have any admin accounts yet you won't be able to use the admin API, so you'll have to edit the database manually. Manually editing the database is generally not recommended so once you have an admin account: use the admin APIs to make further changes.
 
@@ -115,7 +115,7 @@ something like the following in their logs:
 
     2019-09-11 19:32:04,271 - synapse.federation.transport.server - 288 - WARNING - GET-11752 - authenticate_request failed: 401: Invalid signature for server <server> with key ed25519:a_EqML: Unable to verify signature for <server>
 
-This is normally caused by a misconfiguration in your reverse-proxy. See [the reverse proxy docs](docs/reverse_proxy.md) and double-check that your settings are correct.
+This is normally caused by a misconfiguration in your reverse-proxy. See [the reverse proxy docs](../../reverse_proxy.md) and double-check that your settings are correct.
 
 
 Help!! Synapse is slow and eats all my RAM/CPU!
diff --git a/docs/usage/administration/monitoring/reporting_homeserver_usage_statistics.md b/docs/usage/administration/monitoring/reporting_homeserver_usage_statistics.md
index 4e53f9883a..3a7ed7c806 100644
--- a/docs/usage/administration/monitoring/reporting_homeserver_usage_statistics.md
+++ b/docs/usage/administration/monitoring/reporting_homeserver_usage_statistics.md
@@ -78,4 +78,4 @@ If you would like to set up your own statistics collection server and send metri
 consider using one of the following known implementations:
 
 * [Matrix.org's Panopticon](https://github.com/matrix-org/panopticon)
-* [Famedly's Barad-dûr](https://gitlab.com/famedly/company/devops/services/barad-dur)
+* [Famedly's Barad-dûr](https://gitlab.com/famedly/infra/services/barad-dur)
diff --git a/docs/usage/administration/request_log.md b/docs/usage/administration/request_log.md
index 82f5ac7b96..7dd9969d86 100644
--- a/docs/usage/administration/request_log.md
+++ b/docs/usage/administration/request_log.md
@@ -1,6 +1,6 @@
 # Request log format
 
-HTTP request logs are written by synapse (see [`site.py`](../synapse/http/site.py) for details).
+HTTP request logs are written by synapse (see [`synapse/http/site.py`](https://github.com/matrix-org/synapse/tree/develop/synapse/http/site.py) for details).
 
 See the following for how to decode the dense data available from the default logging configuration.
 
diff --git a/docs/usage/configuration/config_documentation.md b/docs/usage/configuration/config_documentation.md
index ec8403c7e9..6cfcce817f 100644
--- a/docs/usage/configuration/config_documentation.md
+++ b/docs/usage/configuration/config_documentation.md
@@ -1321,7 +1321,7 @@ Associated sub-options:
   connection pool. For a reference to valid arguments, see:
     * for [sqlite](https://docs.python.org/3/library/sqlite3.html#sqlite3.connect)
     * for [postgres](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-PARAMKEYWORDS)
-    * for [the connection pool](https://twistedmatrix.com/documents/current/api/twisted.enterprise.adbapi.ConnectionPool.html#__init__)
+    * for [the connection pool](https://docs.twistedmatrix.com/en/stable/api/twisted.enterprise.adbapi.ConnectionPool.html#__init__)
 
 For more information on using Synapse with Postgres,
 see [here](../../postgres.md).
@@ -3981,7 +3981,7 @@ worker_listeners:
 ### `worker_daemonize`
 
 Specifies whether the worker should be started as a daemon process.
-If Synapse is being managed by [systemd](../../systemd-with-workers/README.md), this option
+If Synapse is being managed by [systemd](../../systemd-with-workers/), this option
 must be omitted or set to `false`.
 
 Defaults to `false`.
diff --git a/docs/workers.md b/docs/workers.md
index 59a6487e0d..c21638564e 100644
--- a/docs/workers.md
+++ b/docs/workers.md
@@ -157,7 +157,7 @@ Finally, you need to start your worker processes. This can be done with either
 `synctl` or your distribution's preferred service manager such as `systemd`. We
 recommend the use of `systemd` where available: for information on setting up
 `systemd` to start synapse workers, see
-[Systemd with Workers](systemd-with-workers). To use `synctl`, see
+[Systemd with Workers](systemd-with-workers/). To use `synctl`, see
 [Using synctl with Workers](synctl_workers.md).
 
 
@@ -386,7 +386,7 @@ so. It will then pass those events over HTTP replication to any configured event
 persisters (or the main process if none are configured).
 
 Note that `event_creator`s and `event_persister`s are implemented using the same
-[`synapse.app.generic_worker`](#synapse.app.generic_worker).
+[`synapse.app.generic_worker`](#synapseappgeneric_worker).
 
 An example [`stream_writers`](usage/configuration/config_documentation.md#stream_writers)
 configuration with multiple writers: