Set up efficient local development workflow for Gamma. Use when configuring hot reload, mock responses, or optimizing your Gamma development experience. Trigger with phrases like "gamma local dev", "gamma development setup", "gamma hot reload", "gamma mock", "gamma dev workflow".
npxskills add jeremylongshore/claude-code-plugins-plus-skills--skill gamma-local-dev-loopLoading…
Set up an efficient local development workflow for Gamma API integrations. Since Gamma is a REST API with no SDK, the dev loop centers on HTTP request/response testing, mock servers for offline development, and a reusable client wrapper.
gamma-install-auth setuptsx for TypeScript executionGAMMA_API_KEY in .envgamma-integration/
├── src/
│ ├── client.ts # Reusable Gamma API client
│ ├── generate.ts # Generation workflows
│ └── poll.ts # Polling helper
├── test/
│ ├── mock-server.ts # Local mock for offline dev
│ └── integration.test.ts
├── .env # GAMMA_API_KEY (gitignored)
├── .env.example # Template without secrets
├── package.json
└── tsconfig.json
// src/client.ts
import "dotenv/config";
const GAMMA_BASE = "https://public-api.gamma.app/v1.0";
export interface GammaClient {
generate(body: GenerateRequest): Promise<GenerateResponse>;
poll(generationId: string): Promise<PollResponse>;
listThemes(): Promise<Theme[]>;
listFolders(): Promise<Folder[]>;
}
export function createClient(apiKey?: string, baseUrl?: string): GammaClient {
const key = apiKey ?? process.env.GAMMA_API_KEY;
if (!key) throw new Error("GAMMA_API_KEY required");
const base = baseUrl ?? GAMMA_BASE;
const headers = { "X-API-KEY": key, "Content-Type": "application/json" };
async function request(method: string, path: string, body?: unknown) {
const res = await fetch(`${base}${path}`, {
method,
headers,
body: body ? JSON.stringify(body) : undefined,
});
if (!res.ok) {
const text = await res.text();
throw new Error(`Gamma ${res.status}: ${text}`);
}
return res.json();
}
return {
generate: (body) => request("POST", "/generations", body),
poll: (id) => request("GET", `/generations/${id}`),
listThemes: () => request("GET", "/themes"),
listFolders: () => request("GET", "/folders"),
};
}
// src/poll.ts
import type { GammaClient } from "./client";
export async function waitForCompletion(
client: GammaClient,
generationId: string,
opts = { intervalMs: 5000, timeoutMs: 120000 }
) {
const deadline = Date.now() + opts.timeoutMs;
while (Date.now() < deadline) {
const result = await client.poll(generationId);
if (result.status === "completed") return result;
if (result.status === "failed") throw new Error(`Generation failed: ${result.error}`);
await new Promise((r) => setTimeout(r, opts.intervalMs));
}
throw new Error(`Poll timeout after ${opts.timeoutMs}ms`);
}
// test/mock-server.ts
import http from "node:http";
const MOCK_PORT = 9876;
const generations = new Map<string, { status: string; tick: number }>();
const server = http.createServer((req, res) => {
res.setHeader("Content-Type", "application/json");
// POST /v1.0/generations
if (req.method === "POST" && req.url === "/v1.0/generations") {
const id = `mock_${Date.now()}`;
generations.set(id, { status: "in_progress", tick: 0 });
res.end(JSON.stringify({ generationId: id }));
return;
}
// GET /v1.0/generations/:id — completes after 3 polls
const pollMatch = req.url?.match(/\/v1\.0\/generations\/(.+)/);
if (req.method === "GET" && pollMatch) {
const gen = generations.get(pollMatch[1]);
if (!gen) { res.writeHead(404); res.end("{}"); return; }
gen.tick++;
if (gen.tick >= 3) gen.status = "completed";
res.end(JSON.stringify({
generationId: pollMatch[1],
status: gen.status,
...(gen.status === "completed" && {
gammaUrl: `https://gamma.app/docs/mock-${pollMatch[1]}`,
exportUrl: `https://export.gamma.app/mock.pdf`,
creditsUsed: 10,
}),
}));
return;
}
// GET /v1.0/themes
if (req.url === "/v1.0/themes") {
res.end(JSON.stringify([
{ id: "theme_1", name: "Professional" },
{ id: "theme_2", name: "Modern" },
]));
return;
}
// GET /v1.0/folders
if (req.url === "/v1.0/folders") {
res.end(JSON.stringify([{ id: "folder_1", name: "Test Folder" }]));
return;
}
res.writeHead(404);
res.end("{}");
});
server.listen(MOCK_PORT, () => console.log(`Mock Gamma API on :${MOCK_PORT}`));
{
"scripts": {
"dev:mock": "tsx test/mock-server.ts",
"dev:generate": "tsx src/generate.ts",
"test": "vitest run",
"test:integration": "GAMMA_BASE=http://localhost:9876/v1.0 vitest run test/integration"
}
}
// test/integration.test.ts
import { describe, it, expect } from "vitest";
import { createClient } from "../src/client";
import { waitForCompletion } from "../src/poll";
const BASE = process.env.GAMMA_BASE ?? "http://localhost:9876/v1.0";
describe("Gamma API", () => {
const client = createClient("test-key", BASE);
it("generates and polls to completion", async () => {
const { generationId } = await client.generate({
content: "Test presentation",
outputFormat: "presentation",
});
expect(generationId).toBeTruthy();
const result = await waitForCompletion(client, generationId);
expect(result.status).toBe("completed");
expect(result.gammaUrl).toContain("gamma.app");
});
it("lists workspace themes", async () => {
const themes = await client.listThemes();
expect(themes.length).toBeGreaterThan(0);
});
});
| Activity | Command | Hits Live API? |
|---|---|---|
| Start mock server | npm run dev:mock | No |
| Generate (mock) | GAMMA_BASE=http://localhost:9876/v1.0 npm run dev:generate | No |
| Run tests | npm test (uses mock) | No |
| Live API test | GAMMA_API_KEY=gma_... tsx src/generate.ts | Yes |
| Issue | Cause | Fix |
|---|---|---|
GAMMA_API_KEY required | Missing env var | Add to .env or export |
| Mock returns 404 | Wrong mock port/path | Verify GAMMA_BASE points to mock |
| Poll timeout locally | Mock tick count too high | Reduce tick threshold |
fetch is not defined | Node.js < 18 | Upgrade to Node.js 18+ |
Proceed to gamma-sdk-patterns for reusable API wrapper patterns.
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