diff --git a/cypress/e2e/db_names_with_spaces_spec.cy.js b/cypress/e2e/db_names_with_spaces_spec.cy.js
new file mode 100644
index 00000000..d5d2957c
--- /dev/null
+++ b/cypress/e2e/db_names_with_spaces_spec.cy.js
@@ -0,0 +1,162 @@
+/**
+ * Regression guard for eXide#820: a new leaf name containing a space must be
+ * accepted by the create and rename actions of POST /api/storage/{path}.
+ *
+ * Before the fix, `db:post` passed `$body?name` / `$body?target` to
+ * xmldb:create-collection / xmldb:rename un-encoded, while every *path* in the
+ * module already went through db:encode-path. Those functions reject a raw
+ * space, so the request came back as:
+ *
+ *   400  "failed to convert My Folder into an XmldbURI:
+ *         Illegal character in path at index 2: My Folder"
+ *
+ * (Non-ASCII names such as AéB happened to work, because the xmldb:* functions
+ * escape those internally — which is why dbmanager_spec never caught this.)
+ *
+ * The assertions below cover all three call sites the fix touches: create, the
+ * collection branch of rename, and the resource branch of rename. Each one also
+ * checks the round trip — the listing must show the *decoded* name, so a space
+ * survives storage as %20 and comes back as a space.
+ */
+describe('Names containing spaces (eXide#820)', () => {
+  const base = '/db/cypress-test-spaces'
+  const collWithSpace = 'My Folder'
+  const renamedColl = 'My Renamed Folder'
+  const resource = 'plain.xml'
+  const renamedResource = 'renamed file.xml'
+  const uiColl = 'UI Made Folder'
+
+  function removeTestCollections() {
+    cy.execXQuery(
+      'xquery version "3.1"; ' +
+      'for $c in ("' + base + '", "/db/' + uiColl.replace(/ /g, '%20') + '") ' +
+      'where xmldb:collection-available($c) return xmldb:remove($c)'
+    )
+  }
+
+  function storagePost(path, body) {
+    return cy.request({
+      method: 'POST',
+      url: '/eXide' + '/api/storage' + path,
+      headers: { 'Content-Type': 'application/json' },
+      body: body,
+      failOnStatusCode: false
+    })
+  }
+
+  function listing(path) {
+    return cy.request({
+      method: 'GET',
+      url: '/eXide/api/storage' + path,
+      failOnStatusCode: false
+    })
+  }
+
+  function names(response) {
+    return (response.body.items || []).map((item) => item.name)
+  }
+
+  before(() => {
+    cy.loginXHR('admin', '')
+    removeTestCollections()
+    cy.execXQuery('xquery version "3.1"; xmldb:create-collection("/db", "cypress-test-spaces")')
+  })
+
+  beforeEach(() => {
+    cy.loginXHR('admin', '')
+  })
+
+  after(() => {
+    cy.loginXHR('admin', '')
+    removeTestCollections()
+  })
+
+  it('creates a collection whose name contains a space', () => {
+    storagePost(base, { action: 'create', name: collWithSpace }).then((response) => {
+      // The pre-fix failure mode was a 400 carrying "Illegal character in path".
+      expect(JSON.stringify(response.body)).to.not.contain('Illegal character in path')
+      expect(response.status).to.eq(200)
+      expect(response.body).to.have.property('status', 'ok')
+      // Stored encoded — the leaf is escaped, not rejected.
+      expect(response.body.path).to.contain('My%20Folder')
+    })
+
+    // …and the listing shows it decoded, so the user sees the name they typed.
+    listing(base).then((response) => {
+      expect(response.status).to.eq(200)
+      expect(names(response)).to.include(collWithSpace)
+    })
+  })
+
+  it('renames a collection to a name containing a space', () => {
+    storagePost(base + '/My%20Folder', { action: 'rename', target: renamedColl })
+      .then((response) => {
+        expect(JSON.stringify(response.body)).to.not.contain('Illegal character in path')
+        expect(response.status).to.eq(200)
+        expect(response.body).to.have.property('status', 'ok')
+      })
+
+    listing(base).then((response) => {
+      expect(names(response)).to.include(renamedColl)
+      expect(names(response)).to.not.include(collWithSpace)
+    })
+  })
+
+  it('renames a resource to a name containing a space', () => {
+    // Store a resource with a space-free name first, so the rename is the only
+    // thing under test.
+    cy.request({
+      method: 'PUT',
+      url: '/eXide/api/storage' + base + '/' + resource,
+      headers: { 'Content-Type': 'application/xml' },
+      body: '<test/>'
+    }).its('status').should('eq', 200)
+
+    storagePost(base + '/' + resource, { action: 'rename', target: renamedResource })
+      .then((response) => {
+        expect(JSON.stringify(response.body)).to.not.contain('Illegal character in path')
+        expect(response.status).to.eq(200)
+        expect(response.body).to.have.property('status', 'ok')
+      })
+
+    listing(base).then((response) => {
+      expect(names(response)).to.include(renamedResource)
+      expect(names(response)).to.not.include(resource)
+    })
+  })
+
+  it('creates and deletes a collection with a space through the DB manager UI', () => {
+    cy.visit('/eXide/index.html', {
+      onBeforeLoad(win) {
+        win.localStorage.setItem('eXide.firstTime', '0')
+      }
+    })
+    cy.dismissDialog()
+    // Open the DB manager from the File menu, the way dbmanager_spec does.
+    cy.get('#fullscreen > div.editor-header > div > ul > li:nth-child(1) > a').click()
+    cy.get('#fullscreen > div.editor-header > div > ul > li:nth-child(1) > ul')
+      .find('#menu-file-manager').click()
+    cy.get('div.eXide-browse-main', { timeout: 10000 }).should('be.visible')
+
+    // Create in the default collection (/db), as the manager opens there.
+    cy.get('#eXide-browse-toolbar-create').click()
+    cy.get('#eXide-browse-collection-name').type(uiColl)
+    cy.get('dialog.eXide-dialog[open] .eXide-dialog-buttons button:first-of-type').click()
+
+    cy.get('div.eXide-browse-main').within(() => {
+      cy.contains('.browse-table tbody td.col-name', uiColl, { timeout: 10000 })
+        .should('exist')
+    })
+
+    // Delete it again through the UI, so the round trip covers a path whose
+    // encoded and displayed forms differ.
+    cy.get('div.eXide-browse-main').within(() => {
+      cy.contains('.browse-table tbody td.col-name', uiColl).click()
+    })
+    cy.get('#eXide-browse-toolbar-delete-resource').click()
+    cy.get('dialog.eXide-dialog[open] .eXide-dialog-buttons button:first-of-type').click()
+    cy.get('div.eXide-browse-main').within(() => {
+      cy.contains('.browse-table tbody td.col-name', uiColl).should('not.exist')
+    })
+  })
+})
diff --git a/modules/api/db.xqm b/modules/api/db.xqm
index 2bfafc61..472bae3b 100644
--- a/modules/api/db.xqm
+++ b/modules/api/db.xqm
@@ -81,7 +81,10 @@ declare function db:post($request as map(*)) {
         switch ($action)
             case "create" return
                 try {
-                    let $name := $body?name
+                    (: Encode the new collection name the same way every path in this module is
+                     : encoded. xmldb:create-collection rejects a raw space ("Illegal character
+                     : in path", FORG0001), so an un-encoded leaf name made e.g. "My Folder" fail. :)
+                    let $name := db:encode-path($body?name)
                     let $created := xmldb:create-collection($path, $name)
                     return map { "status": "ok", "path": $created }
                 } catch * {
@@ -126,7 +129,9 @@ declare function db:post($request as map(*)) {
                 }
             case "rename" return
                 try {
-                    let $target := $body?target
+                    (: Encode the new leaf name; xmldb:rename rejects a raw space (FORG0001),
+                     : so an un-encoded target made spaces in renames fail. :)
+                    let $target := db:encode-path($body?target)
                     return
                         if (xmldb:collection-available($path)) then (
                             xmldb:rename($path, $target),