diff --git a/plugins/search-indexer-backend/src/types.ts b/plugins/search-indexer-backend/src/types.ts
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+/*
+ * Copyright 2021 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Base properties that all indexed documents must include, as well as some
+ * common properties that documents are encouraged to use where appropriate.
+ */
+export interface IndexableDocument {
+  /**
+   * The primary name of the document (e.g. name, title, identifier, etc).
+   */
+  title: string;
+
+  /**
+   * Free-form text of the document (e.g. description, content, etc).
+   */
+  text: string;
+
+  /**
+   * The relative or absolute URL of the document (target when a search result
+   * is clicked).
+   */
+  location: string;
+
+  /**
+   * The owner of the document (e.g. spec.owner on a catalog entity).
+   */
+  owner?: string;
+
+  /**
+   * The lifecycle of the document (e.g. spec.lifecycle on a catalog entity).
+   */
+  lifecycle?: string;
+}
+
+/**
+ * Signature for the callback function that implementors must register to have
+ * their documents indexed.
+ */
+export type IndexableDocumentCollator = () => Promise<IndexableDocument[]>;
+
+/**
+ * Signature for the callback function that implementors must register to
+ * decorate existing documents with additional metadata.
+ */
+export type IndexableDocumentDecorator = (
+  documents: IndexableDocument[],
+) => Promise<IndexableDocument[]>;
+
+/**
+ * Parameters required to register a collator.
+ */
+export interface RegisterCollatorParameters {
+  /**
+   * The type of document to be indexed (used to name indices, to configure refresh loop, etc).
+   */
+  type: string;
+
+  /**
+   * The default interval (in seconds) that the provided collator will be called (can be overridden in config).
+   */
+  defaultRefreshIntervalSeconds: number;
+
+  /**
+   * The collator function responsible for returning all documents of the given type.
+   */
+  collator: IndexableDocumentCollator;
+}
+
+/**
+ * Parameters required to register a decorator
+ */
+export interface RegisterDecoratorParameters {
+  /**
+   * The decorator function responsible for appending or modifying documents of the given type(s).
+   */
+  decorator: IndexableDocumentDecorator;
+
+  /**
+   * An optional array of document types that the given decorator should apply to. If none are provided,
+   * the decorator will be applied to all types.
+   */
+  types?: string[];
+}