diff --git a/src/app/credExplorer/App.js b/src/app/credExplorer/App.js
index e88b7be..6b475c2 100644
--- a/src/app/credExplorer/App.js
+++ b/src/app/credExplorer/App.js
@@ -13,7 +13,7 @@ type Props = {};
 type State = {
   repoOwner: string,
   repoName: string,
-  graph: ?Graph<mixed, mixed>,
+  graph: ?Graph,
   pagerankResult: ?PagerankResult,
 };
 
diff --git a/src/app/credExplorer/basicPagerank.js b/src/app/credExplorer/basicPagerank.js
index 55dbc3b..ddeb60f 100644
--- a/src/app/credExplorer/basicPagerank.js
+++ b/src/app/credExplorer/basicPagerank.js
@@ -29,7 +29,7 @@ type OrderedSparseMarkovChain = {|
   +chain: SparseMarkovChain,
 |};
 
-export default function basicPagerank(graph: Graph<any, any>): PagerankResult {
+export default function basicPagerank(graph: Graph): PagerankResult {
   const {nodeOrder, chain} = graphToOrderedSparseMarkovChain(graph);
   const pi = findStationaryDistribution(chain, {verbose: true});
   return distributionToPagerankResult(nodeOrder, pi);
@@ -41,9 +41,7 @@ function edgeWeight(
   return {toWeight: 1, froWeight: 1};
 }
 
-function graphToAddressMapMarkovChain(
-  graph: Graph<any, any>
-): AddressMapMarkovChain {
+function graphToAddressMapMarkovChain(graph: Graph): AddressMapMarkovChain {
   const result = new AddressMap();
   const unnormalizedTotalOutWeights = new AddressMap();
 
@@ -109,7 +107,7 @@ function addressMapMarkovChainToOrderedSparseMarkovChain(
 }
 
 export function graphToOrderedSparseMarkovChain(
-  graph: Graph<any, any>
+  graph: Graph
 ): OrderedSparseMarkovChain {
   return addressMapMarkovChainToOrderedSparseMarkovChain(
     graphToAddressMapMarkovChain(graph)
diff --git a/src/app/credExplorer/pagerankTable.js b/src/app/credExplorer/pagerankTable.js
index 48fe2ee..ba0344a 100644
--- a/src/app/credExplorer/pagerankTable.js
+++ b/src/app/credExplorer/pagerankTable.js
@@ -15,7 +15,7 @@ import type {PagerankResult} from "./basicPagerank";
 
 type Props = {
   pagerankResult: ?PagerankResult,
-  graph: ?Graph<any, any>,
+  graph: ?Graph,
 };
 
 type State = {
@@ -65,7 +65,7 @@ export class PagerankTable extends React.Component<Props, State> {
     if (this.props.graph == null || this.props.pagerankResult == null) {
       throw new Error("Impossible.");
     }
-    const graph: Graph<any, any> = this.props.graph;
+    const graph: Graph = this.props.graph;
     const typesByPlugin: {[pluginName: string]: Set<string>} = {};
     graph.nodes().forEach((node) => {
       if (!typesByPlugin[node.address.pluginName]) {
@@ -154,7 +154,7 @@ export class PagerankTable extends React.Component<Props, State> {
 type RTState = {expanded: boolean};
 type RTProps = {|
   +address: Address,
-  +graph: Graph<any, any>,
+  +graph: Graph,
   +pagerankResult: PagerankResult,
   +depth: number,
 |};
diff --git a/src/cli/commands/pluginGraph.js b/src/cli/commands/pluginGraph.js
index 16a6339..7f35782 100644
--- a/src/cli/commands/pluginGraph.js
+++ b/src/cli/commands/pluginGraph.js
@@ -87,7 +87,7 @@ function pluginGraph(
   }
 }
 
-function display<NP, EP>(promise: Promise<Graph<NP, EP>>) {
+function display(promise: Promise<Graph>) {
   promise.then((graph) => {
     console.log(stringify(graph, {space: 4}));
   });
diff --git a/src/core/graph.js b/src/core/graph.js
index 12f4ca2..3fc1c38 100644
--- a/src/core/graph.js
+++ b/src/core/graph.js
@@ -21,33 +21,33 @@ export type Edge<+T> = {|
   +payload: T,
 |};
 
-type IndexedEdge<+T> = {|
+type IndexedEdge = {|
   +address: Address,
   +srcIndex: Integer,
   +dstIndex: Integer,
-  +payload: T,
+  +payload: any,
 |};
 
 const COMPAT_TYPE = "sourcecred/sourcecred/Graph";
 const COMPAT_VERSION = "0.2.0";
 
-type NodesSortedByStringifiedAddress<NP> = {|
+type NodesSortedByStringifiedAddress = {|
   +address: Address,
-  +payload?: NP,
+  +payload?: any,
 |}[];
-export type GraphJSON<NP, EP> = {|
-  +nodes: NodesSortedByStringifiedAddress<NP>,
-  +edges: AddressMapJSON<IndexedEdge<EP>>,
+export type GraphJSON = {|
+  +nodes: NodesSortedByStringifiedAddress,
+  +edges: AddressMapJSON<IndexedEdge>,
 |};
 
-type MaybeNode<+NP> = {|+address: Address, +node: Node<NP> | void|};
+type MaybeNode = {|+address: Address, +node: Node<any> | void|};
 
-export class Graph<NP, EP> {
+export class Graph {
   // Invariant: sizes of `_nodeIndices`, `_nodes`, `_outEdges`, and
   // `_inEdges` are all equal.
   _nodeIndices: AddressMap<{|+address: Address, +index: Integer|}>;
-  _nodes: MaybeNode<NP>[];
-  _edges: AddressMap<IndexedEdge<EP>>;
+  _nodes: MaybeNode[];
+  _edges: AddressMap<IndexedEdge>;
 
   // If `idx` is the index of a node `v`, then `_outEdges[idx]` is the
   // list of `e.address` for all edges `e` whose source is `v`.
@@ -63,11 +63,11 @@ export class Graph<NP, EP> {
     this._inEdges = [];
   }
 
-  copy(): Graph<$Supertype<NP>, $Supertype<EP>> {
+  copy(): Graph {
     return Graph.mergeConservative(new Graph(), this);
   }
 
-  equals(that: Graph<NP, EP>): boolean {
+  equals(that: Graph): boolean {
     const theseNodes = this.nodes();
     const thoseNodes = that.nodes();
     if (theseNodes.length !== thoseNodes.length) {
@@ -93,13 +93,13 @@ export class Graph<NP, EP> {
     return true;
   }
 
-  toJSON(): Compatible<GraphJSON<NP, EP>> {
+  toJSON(): Compatible<GraphJSON> {
     const partialNodes: {|
       key: string,
       oldIndex: Integer,
       data: {|
         +address: Address,
-        +payload?: NP,
+        +payload?: any,
       |},
     |}[] = this._nodes
       .map((maybeNode, oldIndex) => {
@@ -162,8 +162,8 @@ export class Graph<NP, EP> {
     );
   }
 
-  static fromJSON<NP, EP>(json: Compatible<GraphJSON<NP, EP>>): Graph<NP, EP> {
-    const compatJson: GraphJSON<NP, EP> = fromCompat(
+  static fromJSON(json: Compatible<GraphJSON>): Graph {
+    const compatJson: GraphJSON = fromCompat(
       {
         type: COMPAT_TYPE,
         version: COMPAT_VERSION,
@@ -173,7 +173,7 @@ export class Graph<NP, EP> {
     const result = new Graph();
     compatJson.nodes.forEach((partialNode) => {
       if ("payload" in partialNode) {
-        const node: Node<NP> = (partialNode: any);
+        const node: Node<any> = (partialNode: any);
         result.addNode(node);
       } else {
         result._addNodeAddress(partialNode.address);
@@ -201,7 +201,7 @@ export class Graph<NP, EP> {
     }
   }
 
-  addNode(node: Node<NP>): this {
+  addNode(node: Node<any>): this {
     if (node == null) {
       throw new Error(`node is ${String(node)}`);
     }
@@ -230,7 +230,7 @@ export class Graph<NP, EP> {
     return this;
   }
 
-  addEdge(edge: Edge<EP>): this {
+  addEdge(edge: Edge<any>): this {
     if (edge == null) {
       throw new Error(`edge is ${String(edge)}`);
     }
@@ -245,7 +245,7 @@ export class Graph<NP, EP> {
     return this._addIndexedEdge(indexedEdge);
   }
 
-  _addIndexedEdge(indexedEdge: IndexedEdge<EP>): this {
+  _addIndexedEdge(indexedEdge: IndexedEdge): this {
     const existingIndexedEdge = this._edges.get(indexedEdge.address);
     if (existingIndexedEdge !== undefined) {
       if (deepEqual(existingIndexedEdge, indexedEdge)) {
@@ -283,18 +283,18 @@ export class Graph<NP, EP> {
     return this;
   }
 
-  node(address: Address): Node<NP> {
+  node(address: Address): Node<any> {
     const indexDatum = this._nodeIndices.get(address);
     if (indexDatum == null) {
       // We've never heard of this node.
       return (undefined: any);
     } else {
-      const node: Node<NP> | void = this._nodes[indexDatum.index].node;
-      return ((node: any): Node<NP>);
+      const node: Node<any> | void = this._nodes[indexDatum.index].node;
+      return ((node: any): Node<any>);
     }
   }
 
-  edge(address: Address): Edge<EP> {
+  edge(address: Address): Edge<any> {
     const indexedEdge = this._edges.get(address);
     if (!indexedEdge) {
       // Lie.
@@ -327,7 +327,7 @@ export class Graph<NP, EP> {
       +edgeType?: string,
       +direction?: "IN" | "OUT" | "ANY",
     |}
-  ): {|+edge: Edge<EP>, +neighbor: Address|}[] {
+  ): {|+edge: Edge<any>, +neighbor: Address|}[] {
     if (nodeAddress == null) {
       throw new Error(`address is ${String(nodeAddress)}`);
     }
@@ -338,7 +338,7 @@ export class Graph<NP, EP> {
     }
     const nodeIndex = indexDatum.index;
 
-    let result: {|+edge: Edge<EP>, +neighbor: Address|}[] = [];
+    let result: {|+edge: Edge<any>, +neighbor: Address|}[] = [];
     const direction = (options != null && options.direction) || "ANY";
 
     if (direction === "ANY" || direction === "IN") {
@@ -380,7 +380,7 @@ export class Graph<NP, EP> {
    *
    * If filter is provided, it will return only nodes with the requested type.
    */
-  nodes(filter?: {type?: string}): Node<NP>[] {
+  nodes(filter?: {type?: string}): Node<any>[] {
     /*:: declare function nonNulls<T>(x: (T | void)[]): T[]; */
     let nodes = this._nodes.map((x) => x.node).filter((x) => Boolean(x));
     /*:: nodes = nonNulls(nodes); */
@@ -396,7 +396,7 @@ export class Graph<NP, EP> {
    *
    * If filter is provided, it will return only edges with the requested type.
    */
-  edges(filter?: {type?: string}): Edge<EP>[] {
+  edges(filter?: {type?: string}): Edge<any>[] {
     let edges = this._edges.getAll().map((indexedEdge) => ({
       address: indexedEdge.address,
       src: this._nodes[indexedEdge.srcIndex].address,
@@ -418,13 +418,13 @@ export class Graph<NP, EP> {
    *
    * The existing graph objects are not modified.
    */
-  static merge<NP, EP, N1: NP, E1: EP, N2: NP, E2: EP>(
-    g1: Graph<N1, E1>,
-    g2: Graph<N2, E2>,
-    nodeResolver: (Node<N1>, Node<N2>) => Node<NP>,
-    edgeResolver: (Edge<E1>, Edge<E2>) => Edge<EP>
-  ): Graph<NP, EP> {
-    const result: Graph<NP, EP> = new Graph();
+  static merge(
+    g1: Graph,
+    g2: Graph,
+    nodeResolver: (Node<any>, Node<any>) => Node<any>,
+    edgeResolver: (Edge<any>, Edge<any>) => Edge<any>
+  ): Graph {
+    const result: Graph = new Graph();
     g1.nodes().forEach((node) => {
       if (g2.node(node.address) !== undefined) {
         const resolved = nodeResolver(node, g2.node(node.address));
@@ -460,10 +460,7 @@ export class Graph<NP, EP> {
    * for edges). If this assumption does not hold, this function will
    * raise an error.
    */
-  static mergeConservative<NP, EP, N1: NP, E1: EP, N2: NP, E2: EP>(
-    g1: Graph<N1, E1>,
-    g2: Graph<N2, E2>
-  ): Graph<NP, EP> {
+  static mergeConservative(g1: Graph, g2: Graph): Graph {
     function conservativeResolver<T: Addressable>(
       kinds: string /* used for an error message on mismatch */,
       a: T,
@@ -477,7 +474,7 @@ export class Graph<NP, EP> {
         );
       }
     }
-    const result: Graph<NP, EP> = Graph.merge(
+    const result: Graph = Graph.merge(
       g1,
       g2,
       (u, v) => conservativeResolver("nodes", u, v),
@@ -493,9 +490,7 @@ export class Graph<NP, EP> {
    *
    * but uses a mutable accumulator for improved performance.
    */
-  static mergeManyConservative<NP, EP>(
-    graphs: $ReadOnlyArray<Graph<$Subtype<NP>, $Subtype<EP>>>
-  ): Graph<NP, EP> {
+  static mergeManyConservative(graphs: $ReadOnlyArray<Graph>): Graph {
     const result = new Graph();
     graphs.forEach((graph) => {
       graph.nodes().forEach((node) => {
diff --git a/src/core/graph.test.js b/src/core/graph.test.js
index 9f836e0..6e1267f 100644
--- a/src/core/graph.test.js
+++ b/src/core/graph.test.js
@@ -388,7 +388,7 @@ describe("graph", () => {
     describe("neighborhood detection", () => {
       describe("type filtering", () => {
         class ExampleGraph {
-          graph: Graph<{}, {}>;
+          graph: Graph;
           root: Address;
           idIncrement: number;
           inEdges: {[string]: Edge<{}>};
@@ -891,9 +891,7 @@ describe("graph", () => {
        * node `u`, create a graph with just that node, its neighbors,
        * and its incident edges (in both directions).
        */
-      function neighborhoodDecomposition<NP, EP>(
-        originalGraph: Graph<NP, EP>
-      ): Graph<NP, EP>[] {
+      function neighborhoodDecomposition(originalGraph: Graph): Graph[] {
         return originalGraph.nodes().map((node) => {
           const miniGraph = new Graph();
           miniGraph.addNode(node);
@@ -925,9 +923,7 @@ describe("graph", () => {
        * create a graph with just that edge and its two endpoints, and
        * for each isolated node createa graph with just that node.
        */
-      function edgeDecomposition<NP, EP>(
-        originalGraph: Graph<NP, EP>
-      ): Graph<NP, EP>[] {
+      function edgeDecomposition(originalGraph: Graph): Graph[] {
         const edgeGraphs = originalGraph.edges().map((edge) => {
           const miniGraph = new Graph();
           miniGraph.addNode(originalGraph.node(edge.src));
@@ -1001,17 +997,16 @@ describe("graph", () => {
             payload: null,
           }),
         };
-        const g1: Graph<string, number> = new Graph()
+        const g1: Graph = new Graph()
           .addNode(data.a())
           .addNode(data.b())
           .addEdge(data.u());
-        const g2: Graph<boolean, null> = new Graph()
+        const g2: Graph = new Graph()
           .addNode(data.c())
           .addNode(data.d())
           .addEdge(data.v());
-        type ResultGraph = Graph<string | boolean, number | null>;
-        const result: ResultGraph = Graph.mergeConservative(g1, g2);
-        const expected: ResultGraph = new Graph()
+        const result = Graph.mergeConservative(g1, g2);
+        const expected = new Graph()
           .addNode(data.a())
           .addNode(data.b())
           .addEdge(data.u())
@@ -1022,7 +1017,7 @@ describe("graph", () => {
       });
 
       it("conservatively rejects a graph with conflicting nodes", () => {
-        const makeGraph: (nodePayload: string) => Graph<*, *> = (nodePayload) =>
+        const makeGraph: (nodePayload: string) => Graph = (nodePayload) =>
           new Graph().addNode({
             address: demoData.makeAddress("conflicting-node", "EXPERIMENT"),
             payload: nodePayload,
@@ -1037,7 +1032,7 @@ describe("graph", () => {
       it("conservatively rejects a graph with conflicting edges", () => {
         const srcAddress = demoData.makeAddress("src", "EXPERIMENT");
         const dstAddress = demoData.makeAddress("dst", "EXPERIMENT");
-        const makeGraph: (edgePayload: string) => Graph<*, *> = (edgePayload) =>
+        const makeGraph: (edgePayload: string) => Graph = (edgePayload) =>
           new Graph()
             .addNode({address: srcAddress, payload: {}})
             .addNode({address: dstAddress, payload: {}})
@@ -1149,7 +1144,6 @@ describe("graph", () => {
             address: demoData.makeAddress("hello", "EXPERIMENT"),
             payload: 17,
           };
-          // This will be a Graph<string | number, *>.
           new Graph().addNode(stringNode).addNode(numberNode);
         });
       });
@@ -1176,7 +1170,6 @@ describe("graph", () => {
             dst: dst.address,
             payload: 18,
           };
-          // This will be a Graph<{}, string | number>.
           new Graph()
             .addNode(src)
             .addNode(dst)
@@ -1205,12 +1198,6 @@ describe("graph", () => {
         expect(g1.equals(g2)).toBe(true);
         expect(g1.equals(demoData.advancedMealGraph())).toBe(true);
       });
-
-      function _unused_itAllowsUpcastingPayloadTypes(
-        g: Graph<{x: string, y: number}, boolean>
-      ): Graph<{x: string}, ?boolean> {
-        return g.copy();
-      }
     });
   });
 });
diff --git a/src/core/porcelain.js b/src/core/porcelain.js
index fdd79e9..47ab118 100644
--- a/src/core/porcelain.js
+++ b/src/core/porcelain.js
@@ -4,10 +4,10 @@ import type {Address} from "./address";
 import type {Edge, Graph, Node} from "./graph";
 
 export class NodeReference<+T> {
-  _graph: Graph<any, any>;
+  _graph: Graph;
   _address: Address;
 
-  constructor(g: Graph<any, any>, a: Address) {
+  constructor(g: Graph, a: Address) {
     this._graph = g;
     this._address = a;
   }
@@ -25,7 +25,7 @@ export class NodeReference<+T> {
       }));
   }
 
-  graph(): Graph<any, any> {
+  graph(): Graph {
     return this._graph;
   }
 
diff --git a/src/plugins/artifact/artifactPlugin.js b/src/plugins/artifact/artifactPlugin.js
index 1700bc8..2893fad 100644
--- a/src/plugins/artifact/artifactPlugin.js
+++ b/src/plugins/artifact/artifactPlugin.js
@@ -23,7 +23,7 @@ export type EdgePayload = IncludesEdgePayload;
 const NON_SLUG_CHARACTER: RegExp = /[^a-z]/g;
 
 export function artifactAddress(
-  graph: Graph<NodePayload, EdgePayload>,
+  graph: Graph,
   repoOwner: string,
   repoName: string,
   artifactName: string
diff --git a/src/plugins/artifact/editor/App.js b/src/plugins/artifact/editor/App.js
index 53df539..f98b83b 100644
--- a/src/plugins/artifact/editor/App.js
+++ b/src/plugins/artifact/editor/App.js
@@ -6,14 +6,7 @@ import {StyleSheet, css} from "aphrodite/no-important";
 import "./pluginAdapter";
 
 import type {Graph, Node} from "../../../core/graph";
-import type {
-  NodePayload as GithubNodePayload,
-  EdgePayload as GithubEdgePayload,
-} from "../../github/types";
-import type {
-  NodePayload as ArtifactNodePayload,
-  EdgePayload as ArtifactEdgePayload,
-} from "../artifactPlugin";
+import type {NodePayload as ArtifactNodePayload} from "../artifactPlugin";
 import type {Settings} from "./SettingsConfig";
 import {ArtifactGraphEditor} from "./ArtifactGraphEditor";
 import {ContributionList} from "./ContributionList";
@@ -24,8 +17,8 @@ import standardAdapterSet from "./standardAdapterSet";
 type Props = {};
 type State = {
   artifacts: Node<ArtifactNodePayload>[],
-  githubGraph: ?Graph<GithubNodePayload, GithubEdgePayload>,
-  artifactGraph: ?Graph<ArtifactNodePayload, ArtifactEdgePayload>,
+  githubGraph: ?Graph,
+  artifactGraph: ?Graph,
   settings: Settings,
 };
 
diff --git a/src/plugins/artifact/editor/ArtifactGraphEditor.js b/src/plugins/artifact/editor/ArtifactGraphEditor.js
index 9d449ae..4034653 100644
--- a/src/plugins/artifact/editor/ArtifactGraphEditor.js
+++ b/src/plugins/artifact/editor/ArtifactGraphEditor.js
@@ -4,16 +4,16 @@ import React from "react";
 
 import type {Node} from "../../../core/graph";
 import type {Settings} from "./SettingsConfig";
-import type {NodePayload, EdgePayload} from "../artifactPlugin";
+import type {NodePayload} from "../artifactPlugin";
 import {Graph} from "../../../core/graph";
 import {artifactAddress} from "../artifactPlugin";
 
 type Props = {
   settings: Settings,
-  onChange: (Graph<NodePayload, EdgePayload>) => void,
+  onChange: (Graph) => void,
 };
 type State = {
-  graph: Graph<NodePayload, EdgePayload>,
+  graph: Graph,
   artifactInProgressName: string,
 };
 
diff --git a/src/plugins/artifact/editor/ContributionList.js b/src/plugins/artifact/editor/ContributionList.js
index 1f75d70..da8bb2c 100644
--- a/src/plugins/artifact/editor/ContributionList.js
+++ b/src/plugins/artifact/editor/ContributionList.js
@@ -7,7 +7,7 @@ import {AdapterSet} from "./adapterSet";
 import {Graph} from "../../../core/graph";
 
 type Props = {
-  graph: ?Graph<any, any>,
+  graph: ?Graph,
   adapters: AdapterSet,
 };
 type State = {
@@ -39,7 +39,7 @@ export class ContributionList extends React.Component<Props, State> {
     if (this.props.graph == null) {
       return null;
     }
-    const graph: Graph<any, any> = this.props.graph;
+    const graph: Graph = this.props.graph;
     const typesByPlugin: {[pluginName: string]: Set<string>} = {};
     graph.nodes().forEach((node) => {
       const adapter = this.props.adapters.getAdapter(node);
@@ -88,7 +88,7 @@ export class ContributionList extends React.Component<Props, State> {
     if (this.props.graph == null) {
       return <div>(no graph)</div>;
     } else {
-      const graph: Graph<any, any> = this.props.graph;
+      const graph: Graph = this.props.graph;
       const {typeFilter} = this.state;
       const shouldDisplay: (node: Node<any>) => boolean = typeFilter
         ? (node) => {
diff --git a/src/plugins/artifact/editor/ContributionList.test.js b/src/plugins/artifact/editor/ContributionList.test.js
index 29eadb0..32c9450 100644
--- a/src/plugins/artifact/editor/ContributionList.test.js
+++ b/src/plugins/artifact/editor/ContributionList.test.js
@@ -19,8 +19,6 @@ function createTestData(): * {
   type PayloadA = number;
   type PayloadB = boolean;
   type PayloadC = string;
-  type NodePayload = PayloadA | PayloadB | PayloadC;
-  type EdgePayload = null;
 
   const PLUGIN_A = "sourcecred/example-plugin-a";
   const PLUGIN_B = "sourcecred/example-plugin-b";
@@ -71,7 +69,7 @@ function createTestData(): * {
     dst: nodeA3().address,
   });
 
-  const graph: () => Graph<NodePayload, EdgePayload> = () =>
+  const graph: () => Graph = () =>
     new Graph()
       .addNode(nodeA1())
       .addNode(nodeA2())
@@ -84,7 +82,7 @@ function createTestData(): * {
   const adapterA: () => PluginAdapter<PayloadA> = () => ({
     pluginName: PLUGIN_A,
     renderer: class RendererA extends React.Component<{
-      graph: Graph<any, any>,
+      graph: Graph,
       node: Node<PayloadA>,
     }> {
       render() {
@@ -100,7 +98,7 @@ function createTestData(): * {
         );
       }
     },
-    extractTitle(graph: Graph<NodePayload, EdgePayload>, node: Node<PayloadA>) {
+    extractTitle(graph: Graph, node: Node<PayloadA>) {
       return `the number ${String(node.payload)}`;
     },
   });
@@ -108,7 +106,7 @@ function createTestData(): * {
   const adapterB: () => PluginAdapter<PayloadB> = () => ({
     pluginName: PLUGIN_B,
     renderer: class RendererB extends React.Component<{
-      graph: Graph<any, any>,
+      graph: Graph,
       node: Node<PayloadB>,
     }> {
       render() {
@@ -120,7 +118,7 @@ function createTestData(): * {
         );
       }
     },
-    extractTitle(graph: Graph<NodePayload, EdgePayload>, node: Node<PayloadB>) {
+    extractTitle(graph: Graph, node: Node<PayloadB>) {
       return String(node.payload).toUpperCase() + "!";
     },
   });
diff --git a/src/plugins/artifact/editor/GithubGraphFetcher.js b/src/plugins/artifact/editor/GithubGraphFetcher.js
index 5bcb44c..324303b 100644
--- a/src/plugins/artifact/editor/GithubGraphFetcher.js
+++ b/src/plugins/artifact/editor/GithubGraphFetcher.js
@@ -5,15 +5,11 @@ import React from "react";
 import type {Graph} from "../../../core/graph";
 import type {Settings} from "./SettingsConfig";
 import fetchGithubRepo from "../../github/fetchGithubRepo";
-import type {
-  NodePayload as GithubNodePayload,
-  EdgePayload as GithubEdgePayload,
-} from "../../github/types";
 import {parse} from "../../github/parser";
 
 type Props = {
   settings: Settings,
-  onCreateGraph: (graph: Graph<GithubNodePayload, GithubEdgePayload>) => void,
+  onCreateGraph: (graph: Graph) => void,
 };
 
 export class GithubGraphFetcher extends React.Component<Props> {
diff --git a/src/plugins/artifact/editor/adapters/githubPluginAdapter.js b/src/plugins/artifact/editor/adapters/githubPluginAdapter.js
index 1589d72..0bf32e7 100644
--- a/src/plugins/artifact/editor/adapters/githubPluginAdapter.js
+++ b/src/plugins/artifact/editor/adapters/githubPluginAdapter.js
@@ -23,7 +23,7 @@ const adapter: PluginAdapter<NodePayload> = {
   pluginName: PLUGIN_NAME,
 
   renderer: class GithubNodeRenderer extends React.Component<{
-    graph: Graph<any, any>,
+    graph: Graph,
     node: Node<NodePayload>,
   }> {
     render() {
diff --git a/src/plugins/artifact/editor/pluginAdapter.js b/src/plugins/artifact/editor/pluginAdapter.js
index ea10458..38daae9 100644
--- a/src/plugins/artifact/editor/pluginAdapter.js
+++ b/src/plugins/artifact/editor/pluginAdapter.js
@@ -5,8 +5,6 @@ import type {ComponentType} from "react";
 
 export interface PluginAdapter<-NodePayload> {
   pluginName: string;
-  renderer: $Subtype<
-    ComponentType<{graph: Graph<any, any>, node: Node<NodePayload>}>
-  >;
-  extractTitle(graph: Graph<any, any>, node: Node<NodePayload>): string;
+  renderer: $Subtype<ComponentType<{graph: Graph, node: Node<NodePayload>}>>;
+  extractTitle(graph: Graph, node: Node<NodePayload>): string;
 }
diff --git a/src/plugins/git/cloneGitGraph.js b/src/plugins/git/cloneGitGraph.js
index 0377c2a..2d99b44 100644
--- a/src/plugins/git/cloneGitGraph.js
+++ b/src/plugins/git/cloneGitGraph.js
@@ -2,7 +2,6 @@
 
 import cloneAndLoadRepository from "./cloneAndLoadRepository";
 import {createGraph} from "./createGraph";
-import type {NodePayload, EdgePayload} from "./types";
 import type {Graph} from "../../core/graph";
 
 /**
@@ -18,7 +17,7 @@ import type {Graph} from "../../core/graph";
 export default function fetchGitGraph(
   repoOwner: string,
   repoName: string
-): Graph<NodePayload, EdgePayload> {
+): Graph {
   const repo = cloneAndLoadRepository(repoOwner, repoName);
   return createGraph(repo);
 }
diff --git a/src/plugins/git/createGraph.js b/src/plugins/git/createGraph.js
index 264d5f5..757c6c2 100644
--- a/src/plugins/git/createGraph.js
+++ b/src/plugins/git/createGraph.js
@@ -5,7 +5,6 @@ import type {
   BecomesEdgePayload,
   BlobNodePayload,
   Commit,
-  EdgePayload,
   HasContentsEdgePayload,
   Hash,
   IncludesEdgePayload,
@@ -37,7 +36,7 @@ import {
 import {_makeAddress} from "./address";
 
 class GitGraphCreator {
-  createGraph(repository: Repository): Graph<NodePayload, EdgePayload> {
+  createGraph(repository: Repository): Graph {
     const treeAndNameToSubmoduleUrls = this.treeAndNameToSubmoduleUrls(
       repository
     );
@@ -198,7 +197,7 @@ class GitGraphCreator {
     return result;
   }
 
-  becomesEdges(repository: Repository): Graph<NodePayload, EdgePayload> {
+  becomesEdges(repository: Repository): Graph {
     const result = new Graph();
     for (const {
       childCommit,
@@ -300,8 +299,6 @@ export function* findBecomesEdges(
   }
 }
 
-export function createGraph(
-  repository: Repository
-): Graph<NodePayload, EdgePayload> {
+export function createGraph(repository: Repository): Graph {
   return new GitGraphCreator().createGraph(repository);
 }
diff --git a/src/plugins/git/porcelain.js b/src/plugins/git/porcelain.js
index 8bdb633..46efd95 100644
--- a/src/plugins/git/porcelain.js
+++ b/src/plugins/git/porcelain.js
@@ -60,8 +60,8 @@ function assertAddressType(address: Address, t: NodeType) {
 }
 
 export class GraphPorcelain {
-  graph: Graph<any, any>;
-  constructor(graph: Graph<any, any>) {
+  graph: Graph;
+  constructor(graph: Graph) {
     this.graph = graph;
   }
 
diff --git a/src/plugins/github/fetchGithubGraph.js b/src/plugins/github/fetchGithubGraph.js
index 8731a3a..b6a465a 100644
--- a/src/plugins/github/fetchGithubGraph.js
+++ b/src/plugins/github/fetchGithubGraph.js
@@ -4,7 +4,6 @@
  * docstring of the default export for more details.
  */
 
-import type {NodePayload, EdgePayload} from "./types";
 import type {Graph} from "../../core/graph";
 import fetchGithubRepo from "./fetchGithubRepo";
 import {parse} from "./parser";
@@ -19,13 +18,13 @@ import {parse} from "./parser";
  * @param {String} token
  *    authentication token to be used for the GitHub API; generate a
  *    token at: https://github.com/settings/tokens
- * @return {Promise<Graph<NodePayload, EdgePayload>}
+ * @return {Promise<Graph>}
  *    a promise that resolves to a GitHub contribution graph
  */
 export default function fetchGithubGraph(
   repoOwner: string,
   repoName: string,
   token: string
-): Promise<Graph<NodePayload, EdgePayload>> {
+): Promise<Graph> {
   return fetchGithubRepo(repoOwner, repoName, token).then((x) => parse(x));
 }
diff --git a/src/plugins/github/parser.js b/src/plugins/github/parser.js
index e0076f9..033eb63 100644
--- a/src/plugins/github/parser.js
+++ b/src/plugins/github/parser.js
@@ -6,8 +6,6 @@ import type {Node, Edge} from "../../core/graph";
 import type {
   NodeType,
   EdgeType,
-  NodePayload,
-  EdgePayload,
   PullRequestReviewNodePayload,
   RepositoryNodePayload,
   AuthorNodePayload,
@@ -37,9 +35,7 @@ import {Graph, edgeID} from "../../core/graph";
 import {findReferences} from "./findReferences";
 import {commitAddress} from "../git/address";
 
-export function parse(
-  githubResponseJSON: GithubResponseJSON
-): Graph<NodePayload, EdgePayload> {
+export function parse(githubResponseJSON: GithubResponseJSON): Graph {
   const parser = new GithubParser();
   parser.addData(githubResponseJSON);
   parser.addReferenceEdges();
@@ -47,7 +43,7 @@ export function parse(
 }
 
 class GithubParser {
-  graph: Graph<NodePayload, EdgePayload>;
+  graph: Graph;
 
   constructor() {
     this.graph = new Graph();
diff --git a/src/plugins/github/parser.test.js b/src/plugins/github/parser.test.js
index 7561652..14da766 100644
--- a/src/plugins/github/parser.test.js
+++ b/src/plugins/github/parser.test.js
@@ -1,7 +1,6 @@
 // @flow
 
 import {AUTHORS_EDGE_TYPE, CONTAINS_EDGE_TYPE} from "./types";
-import type {NodePayload, EdgePayload} from "./types";
 import {parse} from "./parser";
 import type {GithubResponseJSON, PullRequestJSON, IssueJSON} from "./graphql";
 import {Graph} from "../../core/graph";
@@ -92,7 +91,7 @@ describe("GithubParser", () => {
   function parseExample({
     issues: issueNums = [],
     prs: prNums = [],
-  }: ExampleInput): Graph<NodePayload, EdgePayload> {
+  }: ExampleInput): Graph {
     const issues = issueNums.map(getIssue);
     const pullRequests = prNums.map(getPR);
     const exampleData: GithubResponseJSON = {
diff --git a/src/plugins/github/porcelain.js b/src/plugins/github/porcelain.js
index 40e5d2a..d7ae79e 100644
--- a/src/plugins/github/porcelain.js
+++ b/src/plugins/github/porcelain.js
@@ -22,7 +22,6 @@ import type {
   AuthorNodePayload,
   AuthorSubtype,
   CommentNodePayload,
-  EdgePayload,
   IssueNodePayload,
   MergedAsEdgePayload,
   NodePayload,
@@ -99,9 +98,9 @@ function asGithubReference(
 }
 
 export class GraphPorcelain {
-  graph: Graph<NodePayload, EdgePayload>;
+  graph: Graph;
 
-  constructor(graph: Graph<NodePayload, EdgePayload>) {
+  constructor(graph: Graph) {
     this.graph = graph;
   }
 
diff --git a/src/tools/loadCombinedGraph.js b/src/tools/loadCombinedGraph.js
index 07d7f04..d7253ad 100644
--- a/src/tools/loadCombinedGraph.js
+++ b/src/tools/loadCombinedGraph.js
@@ -21,14 +21,14 @@ export type EdgePayload = GitEdgePayload | GithubEdgePayload;
  *   the GitHub username of the owner of the repository to be cloned
  * @param {String} repoName
  *   the name of the repository to be cloned
- * @return {Promise<Graph<NodePayload, EdgePayload>>}
+ * @return {Promise<Graph>}
  *   a Promise containing the combined contribution graph
  */
 export function loadCombinedGraph(
   repoOwner: string,
   repoName: string,
   token: string
-): Promise<Graph<NodePayload, EdgePayload>> {
+): Promise<Graph> {
   const githubGraphPromise = fetchGithubGraph(repoOwner, repoName, token);
   const gitGraph = cloneGitGraph(repoOwner, repoName);
   return githubGraphPromise.then((x) => Graph.mergeConservative(gitGraph, x));