diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..5c02fed
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,367 @@
+declare namespace CoreNLP {
+  type CorefAnimacy = 'ANIMATE' | 'INANIMATE' | 'UNKNOWN';
+  type CorefGender = 'FEMALE' | 'MALE' | 'UNKNOWN'
+  type CorefNumber = 'SINGULAR' | 'PLURAL' | 'UNKNOWN';
+  type CorefType = 'PRONOMINAL' | 'NOMINAL' | 'PROPER' | 'LIST';
+
+  class Properties {
+    constructor(props: { [key: string]: any });
+    setProperty(name: string, value: any): void;
+    getProperty(name: string, defaultValue?: any): any;
+    getProperties(): { [key: string]: any };
+    toJSON(): { [key: string]: any };
+    toPropertiessFileContent(): string; // [sic]
+  }
+
+  class Pipeline {
+    constructor(properties: Properties, language: string, connector?: ConnectorServer | ConnectorCLI);
+    getService(): Service;
+    annotate<T extends simple.Annotable>(annotable: T): Promise<T>;
+    assert(methodName?: string, requiredAnnotators?: simple.Annotator[]): void;
+    annotateTokensRegex<T extends simple.Annotable & simple.Expression>(
+      annotable: T,
+      annotateExpression?: boolean,
+    ): Promise<T>;
+    annotateSemgrex<T extends simple.Annotable>(
+      annotable: T,
+      annotateExpression?: boolean,
+    ): Promise<T>;
+    annotateTregex<T extends simple.Annotable>(
+      annotable: T,
+      annotateExpression?: boolean,
+    ): Promise<T>;
+  }
+
+  class Service {
+    constructor(connector: ConnectorServer | ConnectorCLI, language?: string);
+    getAnnotationData(
+      text: string,
+      annotations: simple.Annotator[],
+      options?: { [key: string]: string | number | boolean }
+    ): Promise<unknown>;
+    getTokensRegexData(
+      text: string,
+      pattern: string,
+      annotations: simple.Annotator[],
+      options?: { [key: string]: string | number | boolean }
+    ): Promise<unknown>;
+    getSemgrexData(
+      text: string,
+      pattern: string,
+      annotations: simple.Annotator[],
+      options?: { [key: string]: string | number | boolean }
+    ): Promise<unknown>;
+    static getTokenPosInfo(post: string, languageISO: string): PosInfo;
+    static getSentenceParseInfo(group: string, languageISO: string): SentenceParseInfo;
+    static getGovernorDepInfo(dep: string): DepInfo;
+  }
+
+  class ConnectorCLI {
+    get(
+      config: {
+        annotators: simple.Annotator[],
+        text: string,
+      }
+    ): Promise<unknown>;
+  }
+
+  class ConnectorServer {
+    get(
+      config: {
+        annotators: simple.Annotator[],
+        text: string,
+        options: { [key: string]: string | number | boolean },
+        language: string,
+        utility?: string,
+      }
+    ): Promise<unknown>;
+  }
+
+  interface DocumentJSON {
+    index: number;
+    sentences?: SentenceJSON[];
+    corefs?: CorefMentionJSON[][];
+  }
+
+  interface CorefMentionJSON {
+    id: number;
+    text: string;
+    sentNum: number;
+    headIndex: number;
+    startIndex: number;
+    endIndex: number;
+    isRepresentativeMention: boolean;
+    animacy: CorefAnimacy;
+    gender: CorefGender;
+    number: CorefNumber;
+    type: CorefType;
+    position: [number, number];
+  }
+
+  interface ExpressionJSON {
+    index: number;
+    sentences: ExpressionSentenceMatchJSON[][]
+  }
+
+  interface ExpressionSentenceMatchJSON {
+    begin: number;
+    end: number;
+    text: string;
+    $label?: string;
+  }
+
+  interface ExpressionSentenceMatchGroup {
+    label: string;
+    begin: number;
+    end: number;
+    token?: TokenJSON;
+    $label?: ExpressionSentenceMatchGroup;
+  }
+
+  interface GovernorJSON {
+    dep: string;
+    governor: number;
+    governorGloss: string;
+    dependent: number;
+    dependentGloss: string;
+  }
+
+  interface PosInfo {
+    group: string;
+    tag: string;
+    examples: string[];
+  }
+
+  interface DepInfo {
+    type: string;
+    description: string;
+    examples: string[];
+  }
+
+  interface SentenceParseInfo {
+    description: string;
+    examples: string[];
+  }
+
+  interface TokenJSON {
+    index: number;
+    word: string;
+    originalText: string;
+    characterOffsetBegin: number;
+    characterOffsetEnd: number;
+    before: string;
+    after: string;
+    pos: string;
+    lemma: string;
+    ner: string;
+    speaker: string;
+  }
+
+  interface SentenceJSON {
+    index: number;
+    tokens: TokenJSON[];
+    basicDependencies?: GovernorJSON[];
+    enhancedDependencies?: GovernorJSON[];
+    enhancedPlusPlusDependencies?: GovernorJSON[];
+    parse?: string;
+  }
+
+  namespace simple {
+    class Document extends Annotable {
+      constructor(text: string);
+      fromJSON(data: DocumentJSON): Document;
+      toString(): string;
+      sentences(): Sentence[];
+      corefs(): CorefChain[];
+      coref(index: number): CorefChain;
+      setLanguageISO(iso: string): void;
+      toJSON(): DocumentJSON;
+      static fromJSON(data: DocumentJSON): Document;
+    }
+
+    class Sentence {
+      constructor(text: string);
+      toString(): string;
+      index(): number;
+      parse(): string;
+      words(): string[];
+      word(index: number): string;
+      [Symbol.iterator](): Token[];
+      posTags(): string[];
+      posTag(index: number): string;
+      lemmas(): string[];
+      lemma(index: number): string;
+      nerTags(): string[];
+      nerTag(index: number): string;
+      governors(): Governor[];
+      governor(index: number): Governor;
+      tokens(): Token[];
+      token(index: number): Token;
+      setLanguageISO(iso: string): void;
+      toJSON(): SentenceJSON
+      fromJSON(data: SentenceJSON, isSentence: true): Sentence;
+      fromJSON(data: DocumentJSON, isSentence: false | undefined): Sentence;
+      static fromJSON(data: SentenceJSON, isSentence: true): Sentence;
+      static fromJSON(data: DocumentJSON, isSentence: false | undefined): Sentence;
+    }
+
+    class Governor {
+      constructor(dep: string, dependentToken: Token, governorToken: Token);
+      toString(): string;
+      governor(): Token;
+      governorGloss(): string;
+      dependent(): Token;
+      dependentGloss(): string;
+      dep(): string;
+      depInfo(): DepInfo;
+      toJSON(): GovernorJSON;
+    }
+
+    class Token {
+      constructor(word: string);
+      toString(): string;
+      index(): number;
+      word(): string;
+      originalText(): string;
+      characterOffsetBegin(): number;
+      characterOffsetEnd(): number;
+      before(): string;
+      after(): string;
+      lemma(): string;
+      pos(): string;
+      posInfo(): PosInfo;
+      ner(): string;
+      speaker(): string;
+      toJSON(): TokenJSON;
+      static fromJSON(data: TokenJSON): Token;
+    }
+
+    class Annotator {
+      constructor(
+        name: string,
+        options: { [key: string]: string | boolean },
+        dependencies: Annotator[],
+      );
+      toString(): string;
+      equalsTo(annotator: Annotator): boolean;
+      options(): { [key: string]: string | boolean };
+      option(key: string, value?: string | boolean): string | boolean;
+      dependencies(): Annotator[];
+      pipeline(): string[];
+      pipelineOptions: { [key: string]: string | boolean };
+    }
+
+    class Annotable {
+      constructor(text: string);
+      text(): string;
+      setLanguageISO(iso: string): void;
+      getLanguageISO(): string;
+      addAnnotator(annotator: Annotator): void;
+      removeAnnotator(annotator: Annotator): void;
+      hasAnnotator(annotator: Annotator): boolean;
+      hasAnyAnnotator(annotators: Annotator[]): boolean;
+    }
+
+    class Expression {
+      constructor(text: string, pattern: string);
+      toString(): string;
+      pattern(): string;
+      sentences(): ExpressionSentence[];
+      sentence(index: number): ExpressionSentence;
+      mergeTokensFromDocument(document: Document): Expression;
+      fromJSON(data: ExpressionJSON): Expression;
+      toJSON(): ExpressionJSON;
+      static fromJSON(data: ExpressionJSON): Expression;
+    }
+
+    class ExpressionSentence {
+      constructor(matches: ExpressionSentenceMatch[]);
+      matches(): ExpressionSentenceMatch[];
+      match(index: number): ExpressionSentenceMatch;
+      mergeTokensFromSentence(sentence: Sentence): ExpressionSentence;
+      fromJSON(data: ExpressionSentenceMatchJSON[]): ExpressionSentence;
+      // toJSON seems to be improperly implemented - should return ExpressionSentenceMatchJSON[]
+      toJSON(): ExpressionSentenceMatch[];
+      static fromJSON(data: ExpressionSentenceMatchJSON[]): ExpressionSentence;
+    }
+
+    class ExpressionSentenceMatch {
+      groups(): ExpressionSentenceMatchGroup[];
+      group(label: string): ExpressionSentenceMatchGroup;
+      labels(): string[];
+      fromJSON(data: ExpressionSentenceMatchJSON): ExpressionSentenceMatch;
+      toJSON(): ExpressionSentenceMatchJSON;
+      static fromJSON(data: ExpressionSentenceMatchJSON): ExpressionSentenceMatch;
+    }
+
+    class Node {
+      constructor(pos?: string, word?: string, children?: Node[], parent?: Node);
+      pos(): string;
+      posInfo(): SentenceParseInfo | PosInfo;
+      token(): Token;
+      word(): string;
+      setLanguageISO(iso: string): void;
+      getLanguageISO(): string;
+      children(): Node[];
+      appendChild(node: Node): void;
+      parent(parent?: Node): Node;
+      // not breaking out this type because there are errors/references to other simple types.
+      toJSON(): {
+        pos: string;
+        posInfo: PosInfo;
+        word: string;
+        // this seems to be an error in the function - should return TokenJSON
+        token: Token;
+        // this seems to be an error in the function - should return NodeJSON[];
+        children: Node[];
+      }
+    }
+
+    class Tree {
+      constructor(node: Node);
+      dump(): string;
+      visitDeepFirst(visitor: (node: Node) => void, node?: Node): void;
+      visitDeepFirstRight(visitor: (node: Node) => void, node?: Node): void;
+      visitLeaves(visitor: (node: Node) => void, node?: Node): void;
+      static fromSentence(sentence: Sentence, doubleLink?: boolean): Tree;
+      static fromString(str: string, doubleLink?: boolean): Tree;
+    }
+
+    class CorefMention {
+      constructor();
+      id(): string;
+      text(): string;
+      sentNum(): number;
+      headIndex(): number;
+      startIndex(): number;
+      endIndex(): number;
+      isRepresentativeMention(): boolean;
+      animacy(): CorefAnimacy;
+      gender(): CorefGender;
+      number(): CorefNumber;
+      type(): CorefType;
+      sentence(sentence?: Sentence): Sentence;
+      token(token?: Token): Token;
+      fromJSON(data: CorefMentionJSON): CorefMention;
+      toJSON(): CorefMentionJSON;
+      static fromJSON(data: CorefMentionJSON): CorefMention;
+    }
+
+    class CorefChain {
+      constructor(mentions: CorefMention[]);
+      mentions(): CorefMention[];
+      mention(index: number): CorefMention;
+      representative(): CorefMention;
+      nonRepresentatives(): CorefMention[];
+      document(doc?: Document): Document;
+      fromDocument(doc: Document): CorefChain;
+      fromJSON(data: CorefMention[]): CorefChain;
+      toJSON(): CorefMention[];
+      static fromJSON(data: CorefMention[]): CorefChain;
+    }
+  }
+}
+
+declare module 'corenlp' {
+  export = CoreNLP;
+}
diff --git a/package.json b/package.json
index 34d8750..6e6075d 100644
--- a/package.json
+++ b/package.json
@@ -42,7 +42,8 @@
   "files": [
     "dist",
     "scripts",
-    "examples/runkit.js"
+    "examples/runkit.js",
+    "index.d.ts"
   ],
   "bugs": {
     "url": "https://github.com/gerardobort/node-corenlp/issues"