Junior Backend Software Engineer (Node.js + TypeScript)

We are looking for a Junior Backend Software Engineer to help build and maintain secure, scalable REST APIs for fintech/web3 products. 

You’ll work with TypeScript, Node.js, Express, and MongoDB, generate OpenAPI documentation with TSOA, and integrate services like AWS S3, email/SMS, and third-party providers.

What you’ll do:

- Implement and maintain RESTful APIs using Node.js, TypeScript, Express, and TSOA.

- Model data and write queries using Mongoose; maintain schemas, indexes, and validations.

- Build and document endpoints with TSOA decorators and Swagger/OpenAPI; keep docs up to date.

- Implement authentication/authorization using JWT and bcrypt; apply rate limiting and common security middleware.

- Handle file uploads with Multer and media processing (e.g., Sharp/compress-images) where needed.

- Integrate storage and assets with AWS S3 (SDK v2 and v3) including presigned URLs.

- Build scheduled jobs with node-cron and write simple automation scripts.

- Send transactional emails via Nodemailer with Handlebars templates; assist with SMS or push where applicable (Twilio, Firebase Admin).

- Consume third‑party APIs with Axios or node-fetch; handle retries, timeouts, and error paths.

- Add logging and request tracing with Morgan and Winston; contribute to basic monitoring/debugging.

- Follow linting/formatting standards (ESLint, Prettier), ensure type-safety (TypeScript), and participate in code reviews.

- Support build and run workflows (ts-node, tsc, nodemon, pm2); assist in deployments and environment configuration via dotenv.

- Collaborate with frontend/mobile and product to refine requirements; help triage bugs and production issues.

Our stack (you will use some or all):

- Core: Node.js, TypeScript, Express.

- API design: TSOA, Swagger/OpenAPI.

- Database: MongoDB, Mongoose.

- Auth/Security: JSON Web Tokens, bcryptjs, express-rate-limit, helmet.

- Tooling: ts-node, nodemon, pm2, ESLint, Prettier, TSC, concurrently, dotenv, Winston, Morgan.

Minimum qualifications:

- 0–2 years of backend experience with Node.js and TypeScript (internships and projects count).

- Basic experience building REST APIs with Express and documenting endpoints.

- Familiarity with MongoDB and Mongoose (schemas, models, basic queries).

- Understanding of authentication/authorization concepts (JWT), input validation (Joi), and secure coding basics.

- Comfort with Git/GitHub workflows, code reviews, and branching.

- Able to read and maintain TypeScript types; write clean, readable, and linted code.

- Strong debugging skills and willingness to learn from feedback.

Nice to have:

- Experience with TSOA and Swagger/OpenAPI generation.

- AWS S3 (SDK v2 or v3), presigned URLs, and asset pipelines.

- Image/media processing or file upload flows (Multer, Sharp, compress-images).

- Logging/monitoring practices (Winston, Morgan) and performance considerations.

- Basic knowledge of pm2 and production Node.js processes.

- Web security best practices: rate limiting, CORS, Helmet, input sanitization.

- Exposure to Firebase Admin, Twilio, or email templating with Handlebars.

- Familiarity with ethers.js and web3 concepts (for token/wallet features).

- Experience scheduling/background jobs with node-cron.

- Comfort working with Swagger UI and contributing to API documentation.