diff --git a/src/core/mangabaka/client.ts b/src/core/mangabaka/client.ts
new file mode 100644
index 0000000..506b116
--- /dev/null
+++ b/src/core/mangabaka/client.ts
@@ -0,0 +1,114 @@
+import type { Transport } from "../transport";
+import type {
+  ImageSnapshot, PreviewResult, PublicImage, SaveResult, SeriesLink, SeriesSummary, SubmissionImage,
+} from "./types";
+
+export const API_BASE = "https://api.mangabaka.org";
+export const SITE_BASE = "https://mangabaka.org";
+export const coverFormUrl = (seriesId: number): string => `${SITE_BASE}/data/submissions/series/${seriesId}/images`;
+
+export class MangaBakaError extends Error {
+  constructor(message: string, readonly status: number, readonly body?: unknown) {
+    super(message);
+    this.name = "MangaBakaError";
+  }
+}
+
+const MAX_PAGES = 50;
+
+/** Talks to api.mangabaka.org directly (CORS is open); the token never goes anywhere else. */
+export class MangaBakaClient {
+  constructor(private readonly transport: Transport, private readonly token?: string) {}
+
+  async getSeries(id: number): Promise<SeriesSummary> {
+    return (await this.get<{ data: SeriesSummary }>(`/v1/series/${id}`)).data;
+  }
+
+  getLinks(id: number): Promise<SeriesLink[]> {
+    return this.getAllPages<SeriesLink>(`/v1/series/${id}/links?limit=100`);
+  }
+
+  /** Paginated, `limit` ≤ 50 (spec §2.3). */
+  getImages(id: number): Promise<PublicImage[]> {
+    return this.getAllPages<PublicImage>(`/v1/series/${id}/images?limit=50`);
+  }
+
+  async getImageSnapshot(id: number): Promise<ImageSnapshot> {
+    const body = await this.get<{ data: { data: { images: SubmissionImage[] }; version: number } }>(
+      `/v0/my/submissions/series-images/${id}`, true);
+    return { version: body.data.version, images: body.data.data.images };
+  }
+
+  async previewImages(id: number, version: number, images: SubmissionImage[]): Promise<PreviewResult> {
+    return (await this.post<{ data: PreviewResult }>(`/v0/my/submissions/series-images/${id}/preview`,
+      { version, data: { images } })).data;
+  }
+
+  /** Files a real edit request, always for review. Call only after the user confirmed the preview. */
+  async saveImagesForReview(id: number, version: number, images: SubmissionImage[], userNote: string): Promise<SaveResult> {
+    return (await this.post<{ data: SaveResult }>(`/v0/my/submissions/series-images/${id}`,
+      { version, user_note: userNote, save_mode: "review", data: { images } })).data;
+  }
+
+  private headers(auth: boolean): Record<string, string> {
+    const headers: Record<string, string> = { accept: "application/json" };
+    if (auth) {
+      if (!this.token) throw new MangaBakaError("This needs a MangaBaka personal access token.", 401);
+      headers["x-api-key"] = this.token;
+    }
+    return headers;
+  }
+
+  private async get<T>(path: string, auth = false): Promise<T> {
+    const headers = this.headers(auth);
+    return this.parse<T>(await this.transport.fetch(`${API_BASE}${path}`, { headers }), path);
+  }
+
+  private async post<T>(path: string, body: unknown): Promise<T> {
+    const headers = { ...this.headers(true), "content-type": "application/json" };
+    const res = await this.transport.fetch(`${API_BASE}${path}`, { method: "POST", headers, body: JSON.stringify(body) });
+    return this.parse<T>(res, path);
+  }
+
+  private async getAllPages<T>(path: string): Promise<T[]> {
+    const out: T[] = [];
+    let url: string | null = `${API_BASE}${path}`;
+    for (let page = 0; url && page < MAX_PAGES; page++) {
+      const res = await this.transport.fetch(url, { headers: this.headers(false) });
+      const body = await this.parse<{ data: T[]; pagination?: { next?: string | null } }>(res, path);
+      out.push(...body.data);
+      const next = body.pagination?.next ?? null;
+      url = next && new URL(next).origin === API_BASE ? next : null;
+    }
+    return out;
+  }
+
+  private async parse<T>(res: Response, path: string): Promise<T> {
+    const text = await res.text();
+    let body: unknown;
+    try {
+      body = text ? JSON.parse(text) : undefined;
+    } catch {
+      body = undefined;
+    }
+    if (!res.ok) throw new MangaBakaError(explain(res.status, body, path), res.status, body);
+    if (body === undefined) throw new MangaBakaError(`MangaBaka sent something that isn't JSON for ${path}.`, res.status);
+    return body as T;
+  }
+}
+
+function explain(status: number, body: unknown, path: string): string {
+  const detail = body && typeof body === "object" && "message" in body ? String((body as { message: unknown }).message) : "";
+  switch (status) {
+    case 401:
+      return "MangaBaka rejected the token (401). Check your personal access token.";
+    case 403:
+      return "MangaBaka refused (403): the submissions API needs the contributor role or 25 approved submissions. Use the copy-and-paste path instead.";
+    case 404:
+      return `MangaBaka has no such series (${path}).`;
+    case 409:
+      return "The series' covers changed since they were loaded (409).";
+    default:
+      return `MangaBaka answered HTTP ${status}${detail ? `: ${detail}` : ""}.`;
+  }
+}
diff --git a/src/core/mangabaka/types.ts b/src/core/mangabaka/types.ts
new file mode 100644
index 0000000..8ff634c
--- /dev/null
+++ b/src/core/mangabaka/types.ts
@@ -0,0 +1,70 @@
+// Subset of https://mangabaka.org/api.json (downloaded 2026-10-14) that we use. See spec §2.3.
+import type { ExistingImage } from "../covers";
+import type { ContentRating, ImageType } from "../model";
+
+export interface SeriesSummary {
+  id: number;
+  title: string;
+  type: string;
+  content_rating: string | null;
+}
+
+export interface SeriesLink {
+  url: string;
+  name: string;
+  language: string | null;
+}
+
+/** GET /v1/series/{id}/images item. Has no `is_default`. */
+export interface PublicImage {
+  id: number;
+  series_id: number;
+  type: ImageType;
+  language: string;
+  note: string | null;
+  content_rating: ContentRating;
+  hashes: { sha256?: string | null } | null;
+}
+
+/** OpenAPI `series-images` item. `work_id`, `note` and `index_numeric` keys are required, even when null. */
+export interface SubmissionImage {
+  id: number | null;
+  series_id: number | null;
+  work_id: string | null;
+  url: string;
+  index: string | null;
+  index_numeric: number | null;
+  language: string;
+  type: ImageType;
+  note: string | null;
+  content_rating: ContentRating;
+  is_default: boolean;
+}
+
+export interface ImageSnapshot {
+  version: number;
+  images: SubmissionImage[];
+}
+
+export interface SubmissionChange {
+  field: string;
+  type: "added" | "removed" | "changed";
+  identity?: string;
+  label?: string;
+  details?: Record<string, { old?: unknown; new?: unknown }>;
+}
+
+export interface PreviewResult {
+  has_changes: boolean;
+  changes: SubmissionChange[];
+}
+
+export interface SaveResult {
+  submission_id: number;
+  status: string;
+  changes: SubmissionChange[];
+}
+
+export function toExisting(img: PublicImage): ExistingImage {
+  return { id: img.id, sha256: img.hashes?.sha256 ?? null, language: img.language, type: img.type };
+}
diff --git a/test/mangabaka-client.test.ts b/test/mangabaka-client.test.ts
new file mode 100644
index 0000000..97e4028
--- /dev/null
+++ b/test/mangabaka-client.test.ts
@@ -0,0 +1,98 @@
+import { describe, expect, test } from "bun:test";
+import { MangaBakaClient, MangaBakaError, coverFormUrl } from "../src/core/mangabaka/client";
+import { toExisting, type SubmissionImage } from "../src/core/mangabaka/types";
+import { FakeTransport, json } from "./helpers/fake-transport";
+import { fixtureJson } from "./helpers/fixtures";
+
+const API = "https://api.mangabaka.org";
+
+function publicFake() {
+  return new FakeTransport()
+    .on(`${API}/v1/series/9999`, async () => json(await fixtureJson("mangabaka/series-9999.json")))
+    .on(`${API}/v1/series/9999/links?limit=100`, async () => json(await fixtureJson("mangabaka/links-9999.json")))
+    .on(/\/v1\/series\/9999\/images\?.*page=2/, async () => json(await fixtureJson("mangabaka/images-9999-page2.json")))
+    .on(`${API}/v1/series/9999/images?limit=50`, async () => json(await fixtureJson("mangabaka/images-9999-page1.json")));
+}
+
+describe("public reads (captured fixtures)", () => {
+  test("series, links, and every page of images", async () => {
+    const fake = publicFake();
+    const mb = new MangaBakaClient(fake);
+    expect((await mb.getSeries(9999)).title).toBe("Tower of God");
+    expect((await mb.getLinks(9999)).map((l) => l.url)).toContain("https://www.webtoons.com/-/-/-/list?title_no=95");
+    const images = await mb.getImages(9999);
+    expect(images).toHaveLength(31);
+    expect(fake.calls.some((c) => c.init.headers?.["x-api-key"])).toBe(false);
+    expect(toExisting(images[0]!)).toEqual({
+      id: images[0]!.id, sha256: images[0]!.hashes!.sha256 ?? null, language: images[0]!.language, type: images[0]!.type,
+    });
+  });
+
+  test("a next link to another origin is not followed", async () => {
+    const fake = new FakeTransport().on(`${API}/v1/series/1/images?limit=50`, () =>
+      json({ status: 200, data: [], pagination: { next: "https://evil.example/page2" } }));
+    expect(await new MangaBakaClient(fake).getImages(1)).toEqual([]);
+    expect(fake.calls).toHaveLength(1);
+  });
+
+  test("404 is a MangaBakaError", async () => {
+    const fake = new FakeTransport().on(() => true, () => json({ status: 404, message: "Not found" }, 404));
+    const err = await new MangaBakaClient(fake).getSeries(1).catch((e) => e);
+    expect(err).toBeInstanceOf(MangaBakaError);
+    expect(err.status).toBe(404);
+  });
+});
+
+// Not capturable without a token: shapes built from the OpenAPI spec (spec §2.3). See docs/TODO.md.
+const existing: SubmissionImage = {
+  id: 7193, series_id: 9999, work_id: null, url: "https://example.org/old.jpg", index: "0.1", index_numeric: 0.1,
+  language: "ko", type: "volume", note: "Season Cover 3", content_rating: "safe", is_default: true,
+};
+const snapshotBody = { status: 200, data: { data: { images: [existing] }, version: 1760000000 } };
+const previewBody = { status: 200, data: { has_changes: true, changes: [{ field: "images", type: "added", identity: "https://x/new.jpg" }] } };
+
+describe("submissions (token)", () => {
+  const SUB = `${API}/v0/my/submissions/series-images/9999`;
+
+  test("snapshot, preview and save send the token and the right bodies", async () => {
+    const fake = new FakeTransport()
+      .on((u, i) => u === SUB && (i.method ?? "GET") === "GET", () => json(snapshotBody))
+      .on(`${SUB}/preview`, () => json(previewBody))
+      .on((u, i) => u === SUB && i.method === "POST", () =>
+        json({ status: 200, data: { submission_id: 5, status: "pending", changes: [] } }));
+    const mb = new MangaBakaClient(fake, "mb-test-token");
+    const snapshot = await mb.getImageSnapshot(9999);
+    expect(snapshot).toEqual({ version: 1760000000, images: [existing] });
+    expect((await mb.previewImages(9999, snapshot.version, snapshot.images)).has_changes).toBe(true);
+    const saved = await mb.saveImagesForReview(9999, snapshot.version, snapshot.images, "Add WEBTOON covers");
+    expect(saved.submission_id).toBe(5);
+
+    expect(fake.calls.every((c) => c.init.headers?.["x-api-key"] === "mb-test-token")).toBe(true);
+    expect(JSON.parse(fake.calls[1]!.init.body as string)).toEqual({ version: 1760000000, data: { images: [existing] } });
+    expect(JSON.parse(fake.calls[2]!.init.body as string)).toEqual({
+      version: 1760000000, user_note: "Add WEBTOON covers", save_mode: "review", data: { images: [existing] },
+    });
+  });
+
+  test("no token: refuses before sending anything", async () => {
+    const fake = new FakeTransport();
+    await expect(new MangaBakaClient(fake).getImageSnapshot(9999)).rejects.toMatchObject({ status: 401 });
+    expect(fake.calls).toHaveLength(0);
+  });
+
+  test.each([
+    [403, /25 approved submissions/],
+    [409, /changed since/],
+    [401, /token/],
+  ])("HTTP %i explains itself", async (status, message) => {
+    const fake = new FakeTransport().on(() => true, () => json({ status, message: "x" }, status));
+    const err = await new MangaBakaClient(fake, "mb-t").previewImages(9999, 1, []).catch((e) => e);
+    expect(err).toBeInstanceOf(MangaBakaError);
+    expect(err.status).toBe(status);
+    expect(err.message).toMatch(message);
+  });
+});
+
+test("coverFormUrl", () => {
+  expect(coverFormUrl(9999)).toBe("https://mangabaka.org/data/submissions/series/9999/images");
+});