diff --git a/src/api/loadWeightedGraph.js b/src/api/loadWeightedGraph.js
new file mode 100644
index 0000000..4c49f40
--- /dev/null
+++ b/src/api/loadWeightedGraph.js
@@ -0,0 +1,76 @@
+// @flow
+
+import * as WeightedGraph from "../core/weightedGraph";
+import {type WeightedGraph as WeightedGraphT} from "../core/weightedGraph";
+import * as Weights from "../core/weights";
+import {type Weights as WeightsT} from "../core/weights";
+import {type NodeContraction} from "../core/graph";
+import {TaskReporter} from "../util/taskReporter";
+import {type IdentitySpec} from "../plugins/identity/identity";
+import {contractWeightedGraph} from "../plugins/identity/contractIdentities";
+import {nodeContractions} from "../plugins/identity/nodeContractions";
+import * as Discourse from "../plugins/discourse/loadWeightedGraph";
+import * as Github from "../plugins/github/loadWeightedGraph";
+
+export type LoadWeightedGraphOptions = {|
+  +discourseOptions: ?Discourse.Options,
+  +githubOptions: ?Github.Options,
+  +identitySpec: IdentitySpec,
+  +weightsOverrides: WeightsT,
+|};
+
+export async function loadWeightedGraph(
+  options: LoadWeightedGraphOptions,
+  taskReporter: TaskReporter
+): Promise<WeightedGraphT> {
+  taskReporter.start("load-weighted-graph");
+  const {
+    discourseOptions,
+    githubOptions,
+    identitySpec,
+    weightsOverrides,
+  } = options;
+  const pluginGraphs = await _loadPluginGraphs(
+    discourseOptions,
+    githubOptions,
+    taskReporter
+  );
+  const contractions = nodeContractions(identitySpec);
+  const result = _combineGraphs(pluginGraphs, contractions, weightsOverrides);
+  taskReporter.finish("load-weighted-graph");
+  return result;
+}
+
+export function _loadPluginGraphs(
+  discourseOptions: ?Discourse.Options,
+  githubOptions: ?Github.Options,
+  taskReporter: TaskReporter
+): Promise<$ReadOnlyArray<WeightedGraphT>> {
+  const promises: Promise<WeightedGraphT>[] = [];
+  if (discourseOptions) {
+    const promise = Discourse.loadWeightedGraph(discourseOptions, taskReporter);
+    promises.push(promise);
+  }
+  if (githubOptions) {
+    const promise = Github.loadWeightedGraph(githubOptions, taskReporter);
+    promises.push(promise);
+  }
+  // It's important to use Promise.all so that we can load the plugins in
+  // parallel -- since loading is often IO-bound, this can be a big performance
+  // improvement.
+  return Promise.all(promises);
+}
+
+export function _combineGraphs(
+  graphs: $ReadOnlyArray<WeightedGraphT>,
+  contractions: $ReadOnlyArray<NodeContraction>,
+  weightsOverrides: WeightsT
+): WeightedGraphT {
+  const merged = WeightedGraph.merge(graphs);
+  const contracted = contractWeightedGraph(merged, contractions);
+  const weights = Weights.merge([contracted.weights, weightsOverrides], {
+    nodeResolver: (a, b) => b,
+    edgeResolver: (a, b) => b,
+  });
+  return {graph: contracted.graph, weights};
+}
diff --git a/src/api/loadWeightedGraph.test.js b/src/api/loadWeightedGraph.test.js
new file mode 100644
index 0000000..3e43af1
--- /dev/null
+++ b/src/api/loadWeightedGraph.test.js
@@ -0,0 +1,51 @@
+// @flow
+
+import {node} from "../core/graphTestUtil";
+import * as WeightedGraph from "../core/weightedGraph";
+import * as Weights from "../core/weights";
+import {_combineGraphs} from "./loadWeightedGraph";
+
+describe("api/loadWeightedGraph", () => {
+  // The _combineGraphs subfunction does the "interesting" work here; the
+  // rest is just composing IO heavy stuff (e.g. actually generating the GitHub/
+  // Discourse graphs).
+  describe("_combineGraphs", () => {
+    const foo = node("foo");
+    const bar = node("bar");
+    const zod = node("zod");
+    it("merges the input graphs", () => {
+      const wg1 = WeightedGraph.empty();
+      const wg2 = WeightedGraph.empty();
+      wg1.graph.addNode(foo);
+      wg1.weights.nodeWeights.set(foo.address, 3);
+      wg2.graph.addNode(bar);
+      wg2.weights.nodeWeights.set(bar.address, 3);
+      const expected = WeightedGraph.merge([wg1, wg2]);
+      expect(_combineGraphs([wg1, wg2], [], Weights.empty())).toEqual(expected);
+    });
+    it("uses the provided contractions", () => {
+      const wg = WeightedGraph.empty();
+      wg.graph.addNode(foo);
+      wg.graph.addNode(bar);
+      const contraction = {old: [foo.address, bar.address], replacement: zod};
+      const expected = WeightedGraph.empty();
+      expected.graph.addNode(zod);
+      const combined = _combineGraphs([wg], [contraction], Weights.empty());
+      expect(combined).toEqual(expected);
+    });
+    it("uses the weights as overrides", () => {
+      const wg = WeightedGraph.empty();
+      wg.weights.nodeWeights.set(foo.address, 3);
+      wg.weights.nodeWeights.set(bar.address, 3);
+      const weights = Weights.empty();
+      weights.nodeWeights.set(foo.address, 5);
+      weights.nodeWeights.set(zod.address, 5);
+      const combined = _combineGraphs([wg], [], weights);
+      const expected = WeightedGraph.empty();
+      expected.weights.nodeWeights.set(bar.address, 3);
+      expected.weights.nodeWeights.set(foo.address, 5);
+      expected.weights.nodeWeights.set(zod.address, 5);
+      expect(expected).toEqual(combined);
+    });
+  });
+});
diff --git a/src/plugins/identity/contractIdentities.js b/src/plugins/identity/contractIdentities.js
index 84908be..8960642 100644
--- a/src/plugins/identity/contractIdentities.js
+++ b/src/plugins/identity/contractIdentities.js
@@ -23,7 +23,7 @@ import {type IdentitySpec} from "./identity";
  *
  * For more context on this decision, see discussion in #1591.
  */
-export function _contractWeightedGraph(
+export function contractWeightedGraph(
   wg: WeightedGraphT,
   contractions: $ReadOnlyArray<NodeContraction>
 ): WeightedGraphT {
@@ -62,5 +62,5 @@ export function contractIdentities(
   wg: WeightedGraphT,
   identitySpec: IdentitySpec
 ): WeightedGraphT {
-  return _contractWeightedGraph(wg, nodeContractions(identitySpec));
+  return contractWeightedGraph(wg, nodeContractions(identitySpec));
 }
diff --git a/src/plugins/identity/contractIdentities.test.js b/src/plugins/identity/contractIdentities.test.js
index 8c91b49..3e76cd7 100644
--- a/src/plugins/identity/contractIdentities.test.js
+++ b/src/plugins/identity/contractIdentities.test.js
@@ -3,7 +3,7 @@
 import {node} from "../../core/graphTestUtil";
 import {Graph, NodeAddress} from "../../core/graph";
 import * as Weights from "../../core/weights";
-import {_contractWeightedGraph} from "./contractIdentities";
+import {contractWeightedGraph} from "./contractIdentities";
 
 describe("plugins/identity/contractIdentities", () => {
   const a = node("a");
@@ -16,17 +16,17 @@ describe("plugins/identity/contractIdentities", () => {
     w.nodeWeights.set(NodeAddress.empty, 3);
     return w;
   };
-  describe("_contractWeightedGraph", () => {
+  describe("contractWeightedGraph", () => {
     it("contracts the graph", () => {
       const wg = {graph: graph(), weights: weights()};
-      const contracted = _contractWeightedGraph(wg, contractions());
+      const contracted = contractWeightedGraph(wg, contractions());
       const expected = graph().contractNodes(contractions());
       expect(expected.equals(contracted.graph)).toBe(true);
     });
     it("returns a copy of the weights", () => {
       const ws = weights();
       const wg = {graph: graph(), weights: ws};
-      const contracted = _contractWeightedGraph(wg, contractions());
+      const contracted = contractWeightedGraph(wg, contractions());
       expect(contracted.weights).not.toBe(ws);
       expect(ws).toEqual(contracted.weights);
       // check they can be modified independently
@@ -37,7 +37,7 @@ describe("plugins/identity/contractIdentities", () => {
       const ws = weights();
       ws.nodeWeights.set(a.address, 5);
       const wg = {graph: graph(), weights: ws};
-      expect(() => _contractWeightedGraph(wg, contractions())).toThrow(
+      expect(() => contractWeightedGraph(wg, contractions())).toThrow(
         "Explicit weight 5 on contracted node"
       );
     });