diff --git a/src/v3/plugins/github/__snapshots__/address.test.js.snap b/src/v3/plugins/github/__snapshots__/address.test.js.snap
new file mode 100644
index 0000000..dac3738
--- /dev/null
+++ b/src/v3/plugins/github/__snapshots__/address.test.js.snap
@@ -0,0 +1,193 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`plugins/github/address snapshots as expected: issue 1`] = `
+Object {
+  "address": Array [
+    "sourcecred",
+    "github",
+    "issue",
+    "sourcecred",
+    "example-github",
+    "2",
+  ],
+  "structured": Object {
+    "number": "2",
+    "repo": Object {
+      "name": "example-github",
+      "owner": "sourcecred",
+      "type": "REPO",
+    },
+    "type": "ISSUE",
+  },
+}
+`;
+
+exports[`plugins/github/address snapshots as expected: issueComment 1`] = `
+Object {
+  "address": Array [
+    "sourcecred",
+    "github",
+    "comment",
+    "issue",
+    "sourcecred",
+    "example-github",
+    "2",
+    "373768703",
+  ],
+  "structured": Object {
+    "fragment": "373768703",
+    "parent": Object {
+      "number": "2",
+      "repo": Object {
+        "name": "example-github",
+        "owner": "sourcecred",
+        "type": "REPO",
+      },
+      "type": "ISSUE",
+    },
+    "type": "COMMENT",
+  },
+}
+`;
+
+exports[`plugins/github/address snapshots as expected: pull 1`] = `
+Object {
+  "address": Array [
+    "sourcecred",
+    "github",
+    "pull",
+    "sourcecred",
+    "example-github",
+    "5",
+  ],
+  "structured": Object {
+    "number": "5",
+    "repo": Object {
+      "name": "example-github",
+      "owner": "sourcecred",
+      "type": "REPO",
+    },
+    "type": "PULL",
+  },
+}
+`;
+
+exports[`plugins/github/address snapshots as expected: pullComment 1`] = `
+Object {
+  "address": Array [
+    "sourcecred",
+    "github",
+    "comment",
+    "pull",
+    "sourcecred",
+    "example-github",
+    "5",
+    "396430464",
+  ],
+  "structured": Object {
+    "fragment": "396430464",
+    "parent": Object {
+      "number": "5",
+      "repo": Object {
+        "name": "example-github",
+        "owner": "sourcecred",
+        "type": "REPO",
+      },
+      "type": "PULL",
+    },
+    "type": "COMMENT",
+  },
+}
+`;
+
+exports[`plugins/github/address snapshots as expected: repo 1`] = `
+Object {
+  "address": Array [
+    "sourcecred",
+    "github",
+    "repo",
+    "sourcecred",
+    "example-github",
+  ],
+  "structured": Object {
+    "name": "example-github",
+    "owner": "sourcecred",
+    "type": "REPO",
+  },
+}
+`;
+
+exports[`plugins/github/address snapshots as expected: review 1`] = `
+Object {
+  "address": Array [
+    "sourcecred",
+    "github",
+    "review",
+    "sourcecred",
+    "example-github",
+    "5",
+    "100313899",
+  ],
+  "structured": Object {
+    "fragment": "100313899",
+    "pull": Object {
+      "number": "5",
+      "repo": Object {
+        "name": "example-github",
+        "owner": "sourcecred",
+        "type": "REPO",
+      },
+      "type": "PULL",
+    },
+    "type": "REVIEW",
+  },
+}
+`;
+
+exports[`plugins/github/address snapshots as expected: reviewComment 1`] = `
+Object {
+  "address": Array [
+    "sourcecred",
+    "github",
+    "comment",
+    "review",
+    "sourcecred",
+    "example-github",
+    "5",
+    "100313899",
+    "171460198",
+  ],
+  "structured": Object {
+    "fragment": "171460198",
+    "parent": Object {
+      "fragment": "100313899",
+      "pull": Object {
+        "number": "5",
+        "repo": Object {
+          "name": "example-github",
+          "owner": "sourcecred",
+          "type": "REPO",
+        },
+        "type": "PULL",
+      },
+      "type": "REVIEW",
+    },
+    "type": "COMMENT",
+  },
+}
+`;
+
+exports[`plugins/github/address snapshots as expected: user 1`] = `
+Object {
+  "address": Array [
+    "sourcecred",
+    "github",
+    "userlike",
+    "decentralion",
+  ],
+  "structured": Object {
+    "login": "decentralion",
+    "type": "USERLIKE",
+  },
+}
+`;
diff --git a/src/v3/plugins/github/address.js b/src/v3/plugins/github/address.js
new file mode 100644
index 0000000..10a8ada
--- /dev/null
+++ b/src/v3/plugins/github/address.js
@@ -0,0 +1,199 @@
+// @flow
+
+import {NodeAddress, type NodeAddressT} from "../../core/graph";
+
+export opaque type GithubAddressT: NodeAddressT = NodeAddressT;
+
+const GITHUB_PREFIX = NodeAddress.fromParts(["sourcecred", "github"]);
+function githubAddress(...parts: string[]): GithubAddressT {
+  return NodeAddress.append(GITHUB_PREFIX, ...parts);
+}
+
+export type RepoAddress = {|
+  +type: "REPO",
+  +owner: string,
+  +name: string,
+|};
+export type IssueAddress = {|
+  +type: "ISSUE",
+  +repo: RepoAddress,
+  +number: string,
+|};
+export type PullAddress = {|
+  +type: "PULL",
+  +repo: RepoAddress,
+  +number: string,
+|};
+export type ReviewAddress = {|
+  +type: "REVIEW",
+  +pull: PullAddress,
+  +fragment: string,
+|};
+export type CommentAddress = {|
+  +type: "COMMENT",
+  +parent: IssueAddress | PullAddress | ReviewAddress,
+  +fragment: string,
+|};
+export type UserlikeAddress = {|
+  +type: "USERLIKE",
+  +login: string,
+|};
+
+export type StructuredAddress =
+  | RepoAddress
+  | IssueAddress
+  | PullAddress
+  | ReviewAddress
+  | CommentAddress
+  | UserlikeAddress;
+
+export function structure(x: GithubAddressT): StructuredAddress {
+  function fail() {
+    return new Error(`Bad address: ${NodeAddress.toString(x)}`);
+  }
+  if (!NodeAddress.hasPrefix(x, GITHUB_PREFIX)) {
+    throw fail();
+  }
+  const [_unused_sc, _unused_gh, kind, ...rest] = NodeAddress.toParts(x);
+  switch (kind) {
+    case "repo": {
+      if (rest.length !== 2) {
+        throw fail();
+      }
+      const [owner, name] = rest;
+      return {type: "REPO", owner, name};
+    }
+    case "issue": {
+      if (rest.length !== 3) {
+        throw fail();
+      }
+      const [owner, name, number] = rest;
+      const repo = {type: "REPO", owner, name};
+      return {type: "ISSUE", repo, number};
+    }
+    case "pull": {
+      if (rest.length !== 3) {
+        throw fail();
+      }
+      const [owner, name, number] = rest;
+      const repo = {type: "REPO", owner, name};
+      return {type: "PULL", repo, number};
+    }
+    case "review": {
+      if (rest.length !== 4) {
+        throw fail();
+      }
+      const [owner, name, pullNumber, fragment] = rest;
+      const repo = {type: "REPO", owner, name};
+      const pull = {type: "PULL", repo, number: pullNumber};
+      return {type: "REVIEW", pull, fragment};
+    }
+    case "comment": {
+      if (rest.length < 1) {
+        throw fail();
+      }
+      const [subkind, ...subrest] = rest;
+      switch (subkind) {
+        case "issue": {
+          if (subrest.length !== 4) {
+            throw fail();
+          }
+          const [owner, name, issueNumber, fragment] = subrest;
+          const repo = {type: "REPO", owner, name};
+          const issue = {type: "ISSUE", repo, number: issueNumber};
+          return {type: "COMMENT", parent: issue, fragment};
+        }
+        case "pull": {
+          if (subrest.length !== 4) {
+            throw fail();
+          }
+          const [owner, name, pullNumber, fragment] = subrest;
+          const repo = {type: "REPO", owner, name};
+          const pull = {type: "PULL", repo, number: pullNumber};
+          return {type: "COMMENT", parent: pull, fragment};
+        }
+        case "review": {
+          if (subrest.length !== 5) {
+            throw fail();
+          }
+          const [owner, name, pullNumber, reviewFragment, fragment] = subrest;
+          const repo = {type: "REPO", owner, name};
+          const pull = {type: "PULL", repo, number: pullNumber};
+          const review = {type: "REVIEW", pull, fragment: reviewFragment};
+          return {type: "COMMENT", parent: review, fragment};
+        }
+        default:
+          throw fail();
+      }
+    }
+    case "userlike": {
+      if (rest.length !== 1) {
+        throw fail();
+      }
+      const [login] = rest;
+      return {type: "USERLIKE", login};
+    }
+    default:
+      throw fail();
+  }
+}
+
+export function destructure(x: StructuredAddress): GithubAddressT {
+  switch (x.type) {
+    case "REPO":
+      return githubAddress("repo", x.owner, x.name);
+    case "ISSUE":
+      return githubAddress("issue", x.repo.owner, x.repo.name, x.number);
+    case "PULL":
+      return githubAddress("pull", x.repo.owner, x.repo.name, x.number);
+    case "REVIEW":
+      return githubAddress(
+        "review",
+        x.pull.repo.owner,
+        x.pull.repo.name,
+        x.pull.number,
+        x.fragment
+      );
+    case "COMMENT":
+      switch (x.parent.type) {
+        case "ISSUE":
+          return githubAddress(
+            "comment",
+            "issue",
+            x.parent.repo.owner,
+            x.parent.repo.name,
+            x.parent.number,
+            x.fragment
+          );
+        case "PULL":
+          return githubAddress(
+            "comment",
+            "pull",
+            x.parent.repo.owner,
+            x.parent.repo.name,
+            x.parent.number,
+            x.fragment
+          );
+        case "REVIEW":
+          return githubAddress(
+            "comment",
+            "review",
+            x.parent.pull.repo.owner,
+            x.parent.pull.repo.name,
+            x.parent.pull.number,
+            x.parent.fragment,
+            x.fragment
+          );
+        default:
+          // eslint-disable-next-line no-unused-expressions
+          (x.parent.type: empty);
+          throw new Error(`Bad comment parent type: ${x.parent.type}`);
+      }
+    case "USERLIKE":
+      return githubAddress("userlike", x.login);
+    default:
+      // eslint-disable-next-line no-unused-expressions
+      (x.type: empty);
+      throw new Error(`Unexpected type ${x.type}`);
+  }
+}
diff --git a/src/v3/plugins/github/address.test.js b/src/v3/plugins/github/address.test.js
new file mode 100644
index 0000000..b0f4eac
--- /dev/null
+++ b/src/v3/plugins/github/address.test.js
@@ -0,0 +1,207 @@
+// @flow
+
+import {structure, destructure} from "./address";
+import {NodeAddress} from "../../core/graph";
+
+describe("plugins/github/address", () => {
+  const repo = () => ({
+    type: "REPO",
+    owner: "sourcecred",
+    name: "example-github",
+  });
+  const issue = () => ({type: "ISSUE", repo: repo(), number: "2"});
+  const pull = () => ({type: "PULL", repo: repo(), number: "5"});
+  const review = () => ({type: "REVIEW", pull: pull(), fragment: "100313899"});
+  const issueComment = () => ({
+    type: "COMMENT",
+    parent: issue(),
+    fragment: "373768703",
+  });
+  const pullComment = () => ({
+    type: "COMMENT",
+    parent: pull(),
+    fragment: "396430464",
+  });
+  const reviewComment = () => ({
+    type: "COMMENT",
+    parent: review(),
+    fragment: "171460198",
+  });
+  const user = () => ({type: "USERLIKE", login: "decentralion"});
+  const examples = {
+    repo,
+    issue,
+    pull,
+    review,
+    issueComment,
+    pullComment,
+    reviewComment,
+    user,
+  };
+
+  describe("Structured -> Raw -> Structured is identity", () => {
+    Object.keys(examples).forEach((example) => {
+      it(example, () => {
+        const instance = examples[example]();
+        expect(structure(destructure(instance))).toEqual(instance);
+      });
+    });
+  });
+
+  describe("Raw -> Structured -> Raw is identity", () => {
+    Object.keys(examples).forEach((example) => {
+      it(example, () => {
+        const instance = examples[example]();
+        const raw = destructure(instance);
+        expect(destructure(structure(raw))).toEqual(raw);
+      });
+    });
+  });
+
+  describe("snapshots as expected:", () => {
+    Object.keys(examples).forEach((example) => {
+      it(example, () => {
+        const instance = examples[example]();
+        const raw = NodeAddress.toParts(destructure(instance));
+        expect({address: raw, structured: instance}).toMatchSnapshot();
+      });
+    });
+  });
+
+  describe("errors on", () => {
+    describe("structure(...) with", () => {
+      function expectBadAddress(name: string, parts: $ReadOnlyArray<string>) {
+        it(name, () => {
+          const address = NodeAddress.fromParts([
+            "sourcecred",
+            "github",
+            ...parts,
+          ]);
+          // $ExpectFlowError
+          expect(() => structure(address)).toThrow("Bad address");
+        });
+      }
+      function checkBadCases(
+        partses: $ReadOnlyArray<{|
+          +name: string,
+          +parts: $ReadOnlyArray<string>,
+        |}>
+      ) {
+        let partsAccumulator = [];
+        for (const {name, parts} of partses) {
+          const theseParts = [...partsAccumulator, ...parts];
+          expectBadAddress(name, theseParts);
+          partsAccumulator = theseParts;
+        }
+      }
+      it("undefined", () => {
+        // $ExpectFlowError
+        expect(() => structure(undefined)).toThrow("undefined");
+      });
+      it("null", () => {
+        // $ExpectFlowError
+        expect(() => structure(null)).toThrow("null");
+      });
+      it("with bad prefix", () => {
+        // $ExpectFlowError
+        expect(() => structure(NodeAddress.fromParts(["foo"]))).toThrow(
+          "Bad address"
+        );
+      });
+      expectBadAddress("no kind", []);
+      describe("repository with", () => {
+        checkBadCases([
+          {name: "no owner", parts: ["repo"]},
+          {name: "no name", parts: ["owner"]},
+          {name: "extra parts", parts: ["name", "foo"]},
+        ]);
+      });
+      describe("issue with", () => {
+        checkBadCases([
+          {name: "no owner", parts: ["issue"]},
+          {name: "no name", parts: ["owner"]},
+          {name: "no number", parts: ["name"]},
+          {name: "extra parts", parts: ["123", "foo"]},
+        ]);
+      });
+      describe("pull request with", () => {
+        checkBadCases([
+          {name: "no owner", parts: ["pull"]},
+          {name: "no name", parts: ["owner"]},
+          {name: "no number", parts: ["name"]},
+          {name: "extra parts", parts: ["123", "foo"]},
+        ]);
+      });
+      describe("pull request review with", () => {
+        checkBadCases([
+          {name: "no owner", parts: ["review"]},
+          {name: "no name", parts: ["owner"]},
+          {name: "no number", parts: ["name"]},
+          {name: "no fragment", parts: ["123"]},
+          {name: "extra parts", parts: ["987", "foo"]},
+        ]);
+      });
+      describe("comment", () => {
+        expectBadAddress("with no subkind", ["comment"]);
+        expectBadAddress("with bad subkind", ["comment", "icecream"]);
+        describe("on issue with", () => {
+          checkBadCases([
+            {name: "no owner", parts: ["comment", "issue"]},
+            {name: "no name", parts: ["owner"]},
+            {name: "no number", parts: ["name"]},
+            {name: "no fragment", parts: ["123"]},
+            {name: "extra parts", parts: ["987", "foo"]},
+          ]);
+        });
+        describe("on pull request with", () => {
+          checkBadCases([
+            {name: "no owner", parts: ["comment", "pull"]},
+            {name: "no name", parts: ["owner"]},
+            {name: "no number", parts: ["name"]},
+            {name: "no fragment", parts: ["123"]},
+            {name: "extra parts", parts: ["987", "foo"]},
+          ]);
+        });
+        describe("on pull request review with", () => {
+          checkBadCases([
+            {name: "no owner", parts: ["comment", "review"]},
+            {name: "no name", parts: ["owner"]},
+            {name: "no number", parts: ["name"]},
+            {name: "no review fragment", parts: ["123"]},
+            {name: "no comment fragment", parts: ["987"]},
+            {name: "extra parts", parts: ["654", "foo"]},
+          ]);
+        });
+      });
+      describe("userlike", () => {
+        checkBadCases([
+          {name: "no login", parts: ["userlike"]},
+          {name: "extra parts", parts: ["decentra", "lion"]},
+        ]);
+      });
+    });
+
+    describe("destructure(...) with", () => {
+      it("null", () => {
+        // $ExpectFlowError
+        expect(() => destructure(null)).toThrow("null");
+      });
+      it("undefined", () => {
+        // $ExpectFlowError
+        expect(() => destructure(undefined)).toThrow("undefined");
+      });
+      it("bad type", () => {
+        // $ExpectFlowError
+        expect(() => destructure({type: "ICE_CREAM"})).toThrow(
+          "Unexpected type"
+        );
+      });
+      it("bad comment type", () => {
+        expect(() => {
+          // $ExpectFlowError
+          destructure({type: "COMMENT", parent: {type: "ICE_CREAM"}});
+        }).toThrow("Bad comment parent type");
+      });
+    });
+  });
+});