diff --git a/packages/social/stackernews/src/index.test.ts b/packages/social/stackernews/src/index.test.ts
index e7c78aef..fd8a27ad 100644
--- a/packages/social/stackernews/src/index.test.ts
+++ b/packages/social/stackernews/src/index.test.ts
@@ -1,4 +1,131 @@
-import { smokeTest } from '@profullstack/sh1pt-core/testing';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { contractTestSocial, fakeConnectContext } from '@profullstack/sh1pt-core/testing';
 import adapter from './index.js';
 
-smokeTest(adapter, { idPrefix: 'social' });
+contractTestSocial(adapter, {
+  sampleConfig: { territory: 'meta' },
+  samplePost: { title: 'Hello Stacker News', body: 'hello from sh1pt contract tests' },
+  requiredSecrets: ['STACKERNEWS_COOKIE'],
+});
+
+afterEach(() => {
+  vi.restoreAllMocks();
+});
+
+describe('social-stackernews GraphQL posting', () => {
+  it('creates a link post with the Stacker News upsertLink mutation', async () => {
+    const fetchMock = vi.spyOn(globalThis, 'fetch').mockResolvedValue({
+      ok: true,
+      status: 200,
+      json: async () => ({
+        data: {
+          upsertLink: {
+            id: 55,
+            createdAt: '2026-05-21T00:00:00.000Z',
+            item: {
+              id: 123,
+              title: 'Release shipped',
+              url: 'https://sh1pt.com',
+              createdAt: '2026-05-21T00:01:00.000Z',
+            },
+          },
+        },
+      }),
+    } as any);
+
+    const ctx = {
+      ...fakeConnectContext({ STACKERNEWS_COOKIE: 'next-auth.session-token=test' }),
+      dryRun: false,
+    };
+
+    const result = await adapter.post(ctx as any, {
+      title: 'Release shipped',
+      body: 'Article body',
+      link: 'https://sh1pt.com',
+      hashtags: ['bitcoin', 'shipping', 'automation', 'ignored'],
+    }, {
+      territory: 'bitcoin',
+      apiUrl: 'https://stacker.test/api/graphql',
+    });
+
+    expect(result).toEqual({
+      id: '123',
+      url: 'https://stacker.news/items/123',
+      platform: 'stackernews',
+      publishedAt: '2026-05-21T00:01:00.000Z',
+    });
+    expect(fetchMock).toHaveBeenCalledOnce();
+    const [url, init] = fetchMock.mock.calls[0] as [string, RequestInit];
+    expect(url).toBe('https://stacker.test/api/graphql');
+    expect(init.method).toBe('POST');
+    expect(init.headers).toMatchObject({
+      'content-type': 'application/json',
+      cookie: 'next-auth.session-token=test',
+    });
+
+    const body = JSON.parse(String(init.body));
+    expect(body.query).toContain('upsertLink');
+    expect(body.variables).toEqual({
+      subNames: ['bitcoin'],
+      title: 'Release shipped',
+      url: 'https://sh1pt.com',
+      text: 'Article body\n\n#bitcoin #shipping #automation',
+    });
+  });
+
+  it('creates a discussion post when no link is present', async () => {
+    const fetchMock = vi.spyOn(globalThis, 'fetch').mockResolvedValue({
+      ok: true,
+      status: 200,
+      json: async () => ({
+        data: {
+          upsertDiscussion: {
+            id: 56,
+            createdAt: '2026-05-21T00:00:00.000Z',
+            item: { id: 124, title: 'Ask SN', createdAt: '2026-05-21T00:02:00.000Z' },
+          },
+        },
+      }),
+    } as any);
+
+    const ctx = {
+      ...fakeConnectContext({ STACKERNEWS_COOKIE: 'next-auth.session-token=test' }),
+      dryRun: false,
+    };
+
+    await expect(adapter.post(ctx as any, {
+      title: 'Ask SN',
+      body: 'What should sh1pt support next?',
+    }, { territory: 'meta', apiUrl: 'https://stacker.test/api/graphql' })).resolves.toMatchObject({
+      id: '124',
+      url: 'https://stacker.news/items/124',
+    });
+
+    const body = JSON.parse(String((fetchMock.mock.calls[0] as [string, RequestInit])[1].body));
+    expect(body.query).toContain('upsertDiscussion');
+    expect(body.variables).toMatchObject({
+      subNames: ['meta'],
+      title: 'Ask SN',
+      text: 'What should sh1pt support next?',
+    });
+  });
+
+  it('throws GraphQL error messages', async () => {
+    vi.spyOn(globalThis, 'fetch').mockResolvedValue({
+      ok: true,
+      status: 200,
+      json: async () => ({ errors: [{ message: 'insufficient sats' }] }),
+    } as any);
+
+    const ctx = {
+      ...fakeConnectContext({ STACKERNEWS_COOKIE: 'next-auth.session-token=test' }),
+      dryRun: false,
+    };
+
+    await expect(adapter.post(ctx as any, {
+      title: 'Release shipped',
+      body: 'Article body',
+      link: 'https://sh1pt.com',
+    }, { apiUrl: 'https://stacker.test/api/graphql' })).rejects.toThrow('insufficient sats');
+  });
+});
diff --git a/packages/social/stackernews/src/index.ts b/packages/social/stackernews/src/index.ts
index aad495dc..5e36b2da 100644
--- a/packages/social/stackernews/src/index.ts
+++ b/packages/social/stackernews/src/index.ts
@@ -1,30 +1,49 @@
-import { defineSocial, tokenSetup } from '@profullstack/sh1pt-core';
+import { defineSocial, tokenSetup, type SocialPost } from '@profullstack/sh1pt-core';
 
 // Stacker News (stacker.news) — Bitcoin Lightning-themed HN alternative.
 // Submissions cost satoshis to post (anti-spam). GraphQL API at
 // stacker.news/api/graphql. Auth via cookie-based login or nostr
 // NIP-46 — browser-mode is the current practical path.
 interface Config {
-  mode: 'browser';
+  mode?: 'api' | 'browser';
   territory?: string;           // e.g. 'bitcoin', 'ai', 'meta'
+  cookieKey?: string;
+  apiUrl?: string;
 }
 
+const DEFAULT_API = 'https://stacker.news/api/graphql';
+const DEFAULT_COOKIE_KEY = 'STACKERNEWS_COOKIE';
+
 export default defineSocial<Config>({
   id: 'social-stackernews',
   label: 'Stacker News',
   requires: { maxBodyChars: 20_000, maxHashtags: 3 },
   async connect(ctx) {
-    if (!ctx.secret('STACKERNEWS_COOKIE')) {
-      throw new Error('STACKERNEWS_COOKIE not in vault (export cookie from logged-in browser)');
+    if (!ctx.secret(DEFAULT_COOKIE_KEY)) {
+      throw new Error(`${DEFAULT_COOKIE_KEY} not in vault (export cookie from logged-in browser)`);
     }
     return { accountId: 'stackernews' };
   },
   async post(ctx, post, config) {
+    if (!post.title) throw new Error('Stacker News requires a title');
+    const cookieKey = config.cookieKey ?? DEFAULT_COOKIE_KEY;
+    const cookie = ctx.secret(cookieKey);
+    if (!cookie) throw new Error(`${cookieKey} not in vault (export cookie from logged-in browser)`);
+
     ctx.log(`stacker news · territory=${config.territory ?? 'meta'} · note: submissions cost sats`);
     if (ctx.dryRun) return { id: 'dry-run', url: 'https://stacker.news/', platform: 'stackernews', publishedAt: new Date().toISOString() };
-    // TODO: POST to /api/graphql with createItem mutation — note users must
-    // have satoshi balance on their SN account before calling.
-    return { id: `sn_${Date.now()}`, url: 'https://stacker.news/', platform: 'stackernews', publishedAt: new Date().toISOString() };
+
+    const payIn = post.link
+      ? await upsertLink(ctx, post, config, cookie)
+      : await upsertDiscussion(ctx, post, config, cookie);
+    const item = payIn.item;
+    const id = String(item?.id ?? payIn.id);
+    return {
+      id,
+      url: item?.id ? `https://stacker.news/items/${item.id}` : 'https://stacker.news/',
+      platform: 'stackernews',
+      publishedAt: new Date(item?.createdAt ?? payIn.createdAt ?? Date.now()).toISOString(),
+    };
   },
 
   setup: tokenSetup({
@@ -38,3 +57,106 @@ export default defineSocial<Config>({
     ],
   }),
 });
+
+async function upsertLink(
+  ctx: { log(m: string): void },
+  post: SocialPost,
+  config: Config,
+  cookie: string,
+): Promise<StackerPayIn> {
+  const data = await stackerGraphql<{ upsertLink: StackerPayIn }>(config, cookie, {
+    query: `
+      mutation UpsertStackerNewsLink($subNames: [String!], $title: String!, $url: String!, $text: String) {
+        upsertLink(subNames: $subNames, title: $title, url: $url, text: $text) {
+          id
+          createdAt
+          item { id title url createdAt }
+        }
+      }
+    `,
+    variables: {
+      subNames: [config.territory ?? 'meta'],
+      title: post.title,
+      url: post.link,
+      text: formatText(post),
+    },
+  });
+  ctx.log(`stacker news link submitted · payIn=${data.upsertLink.id}`);
+  return data.upsertLink;
+}
+
+async function upsertDiscussion(
+  ctx: { log(m: string): void },
+  post: SocialPost,
+  config: Config,
+  cookie: string,
+): Promise<StackerPayIn> {
+  const data = await stackerGraphql<{ upsertDiscussion: StackerPayIn }>(config, cookie, {
+    query: `
+      mutation UpsertStackerNewsDiscussion($subNames: [String!], $title: String!, $text: String) {
+        upsertDiscussion(subNames: $subNames, title: $title, text: $text) {
+          id
+          createdAt
+          item { id title createdAt }
+        }
+      }
+    `,
+    variables: {
+      subNames: [config.territory ?? 'meta'],
+      title: post.title,
+      text: formatText(post),
+    },
+  });
+  ctx.log(`stacker news discussion submitted · payIn=${data.upsertDiscussion.id}`);
+  return data.upsertDiscussion;
+}
+
+async function stackerGraphql<T>(
+  config: Config,
+  cookie: string,
+  body: { query: string; variables: Record<string, unknown> },
+): Promise<T> {
+  const res = await fetch(config.apiUrl ?? DEFAULT_API, {
+    method: 'POST',
+    headers: {
+      'content-type': 'application/json',
+      cookie,
+    },
+    body: JSON.stringify(body),
+  });
+  const payload = await readStackerResponse<T>(res);
+  if (!res.ok || payload.errors?.length) {
+    throw new Error(payload.errors?.map((err) => err.message).join('; ') || `Stacker News API error ${res.status}`);
+  }
+  if (!payload.data) throw new Error('Stacker News API response did not include data');
+  return payload.data;
+}
+
+async function readStackerResponse<T>(res: Response): Promise<StackerGraphqlResponse<T>> {
+  try {
+    return await res.json() as StackerGraphqlResponse<T>;
+  } catch {
+    return { errors: [{ message: res.statusText }] };
+  }
+}
+
+function formatText(post: SocialPost): string {
+  const tags = (post.hashtags ?? []).slice(0, 3).map((tag) => `#${tag}`).join(' ');
+  return [post.body, tags].filter(Boolean).join('\n\n').slice(0, 20_000);
+}
+
+interface StackerGraphqlResponse<T> {
+  data?: T;
+  errors?: Array<{ message: string }>;
+}
+
+interface StackerPayIn {
+  id: number | string;
+  createdAt?: string;
+  item?: {
+    id: number | string;
+    title?: string;
+    url?: string;
+    createdAt?: string;
+  } | null;
+}