Python Backend Internship Guide for Thiagarajar College of Engineering Students: Choosing a First API Project

Pick the smallest API that still forces you to use authentication, a real database and automated tests. For most students that means a two-resource service, such as users and notes or books and loans, built with FastAPI, Flask or Django REST Framework. The selector below matches project ideas to your current skill level so you finish something reviewable instead of abandoning something ambitious.

Why the first API project matters more than the framework

Recruiters and internship mentors reading a backend portfolio look for the same few things. They want to see that requests are validated, that data is stored with sensible structure, that private endpoints are protected, and that tests show the code works. A project that does these four things in 400 lines is stronger than a sprawling one with a hundred endpoints and no tests.

The framework is a secondary choice. FastAPI gives automatic documentation and type-driven validation. Flask is minimal and teaches you what you are assembling yourself. Django REST Framework gives you an ORM, an admin and authentication out of the box. All three are acceptable. Choose the one you can run locally today, and do not switch halfway.

The starter-project selector

Use this table to choose. Be honest about your level: if you have never deployed or written a test, start at Level 1, even if you have finished several Python courses.

How to use the table in five minutes

1. Pick your level based on the checklist in the next section.
2. Choose the idea that matches something you already use, such as notes, expenses or bookings. Domain familiarity reduces design guesswork.
3. Write down the three or four endpoints you will build first. Cut anything beyond that.
4. Set a finish line: for a two-week effort, aim for working endpoints, auth, a schema diagram and ten or more tests.

Find your level honestly

• Level 1: You can write Python functions and classes, but you have not built a web service that stores data.
• Level 2: You have built one CRUD API and can explain what a foreign key does and why passwords are hashed.
• Level 3: You have written tests against a database, used migrations, and can explain the difference between authentication and authorisation.
• Level 4: You have deployed something, handled a bug in production-like conditions, and can reason about transactions and concurrency.

Authentication: what to build and in what order

Authentication is where beginners most often copy code they do not understand. Build it in layers so each step is testable.

1. Registration with password hashing. Store only a salted hash, using a maintained library such as passlib or Django’s built-in hashers. Never store plain text.
2. Login that issues a token. A signed JSON Web Token with a short expiry is the common choice. Keep the secret in an environment variable, not in the repository.
3. A protected route. Write a dependency or decorator that rejects missing, malformed or expired tokens with a 401 response.
4. Ownership checks. Authenticated is not the same as allowed. Every query for user data should filter by the current user’s id, and return 404 or 403 when the row belongs to someone else.
5. Roles, only at Level 2 and above. Add an is_admin flag or a role column before attempting anything like OAuth2.

Skip social login and OAuth providers in a first project. They add configuration work without teaching you much about your own API.

Database design: a short worksheet

Before writing models, answer these questions on paper. Ten minutes here prevents a rewrite later.

• What are the nouns in my project? Each is a candidate table.
• Which noun belongs to which? That gives you the foreign keys.
• Which fields must be unique (email, username, ISBN)? Declare it in the schema, not only in code.
• Which fields can be null, and does null mean something specific?
• Which columns will I filter or sort by? Those are index candidates.
• What happens when a parent row is deleted? Choose cascade, restrict or soft delete deliberately.

Use SQLite while developing, since it needs no setup. If you reach Level 3, move to PostgreSQL so you meet real constraints, transactions and migration behaviour. Use a migration tool (Alembic for SQLAlchemy, built-in migrations for Django) from the start, so your schema history is visible in the repository.

Tests: the minimum credible suite

Use pytest. Whichever framework you pick, a test client lets you call endpoints without starting a server. Aim for a suite that covers the following.

• Each endpoint’s success case.
• Validation failures: missing fields, wrong types, values out of range.
• Authentication failures: no token, bad token, expired token.
• Authorisation failures: one user trying to access another user’s data.
• One business rule specific to your project.

Use a separate test database, reset between tests through fixtures. If a test depends on the order other tests ran in, it is a bug in the test.

Worked example (illustrative): an expense tracker at Level 2

The following is an illustrative plan, not a record of code that was run. It shows how the selector translates into an actual scope.

Scope

Three tables: users, categories and expenses. An expense belongs to one user and one category. Four endpoints to begin with.

POST   /auth/register
POST   /auth/login
POST   /expenses
GET    /expenses?month=2026-11
GET    /reports/monthly?month=2026-11

Schema decisions

• expenses.amount stored as an integer in paise, avoiding floating-point rounding.
• Composite index on (user_id, spent_on) because every list query filters by user and date.
• Category names unique per user, not globally.

Planned tests

1. Registering the same email twice returns a conflict error.
2. Logging in with a wrong password returns 401.
3. Creating an expense without a token returns 401.
4. User A creates an expense; user B’s list for the same month is empty.
5. The monthly report totals three expenses correctly, including one on the last day of the month.
6. A negative amount is rejected with a validation error.

The ownership test (number 4) and the boundary-date test (number 5) are the ones that tend to expose real bugs, so write them first.

A two-week schedule that fits a short internship

If you are following a structured short programme, a plan like this keeps scope under control. CareerSwami offers a free two-week online internship across 26 tracks, with a free offer letter and a free completion certificate after successful completion. A Python and backend track gives you a deadline to organise this plan around.

Common mistakes that cost marks and credibility

• Secrets committed to Git. Use a .env file listed in .gitignore and provide a .env.example.
• Returning password hashes in responses. Use separate response schemas from database models.
• One giant file. Split into routers, models, schemas and services once you pass roughly 300 lines.
• Tests that hit your real database. Always point tests at a throwaway one.
• Inconsistent status codes. Use 201 for creation, 204 for empty success, 400 or 422 for validation, 401 for unauthenticated, 403 for forbidden and 404 for missing.
• No pagination. Even a small list endpoint should accept limit and offset.

Building a first API project at TCE: internship credits, syllabus and who to ask

CareerSwami is independent and is not affiliated with the college. For a Python backend project, the useful question is how the work fits TCE’s own internship rules, which the college sets itself. TCE’s B.E./B.Tech. Regulations (CBCS 2022-23) were approved by its own Academic Council in June 2022, so the college’s documents, not a general guide, decide what counts. Check that the version applying to your batch is current.

Under those 2022 regulations, every student must complete an internship in an industry or at the institution. Two weeks equal one credit, and the degree requires 3 credits (6 weeks). These credits are not counted in GPA/CGPA. A faculty team nominated by the Head of Department evaluates the internship report and awards the grade and credit. In practice, a two-week API project plan like the one in this guide covers only a third of the minimum, and the final report must satisfy your department’s evaluators, not just a reviewer on GitHub. Keep a dated log, commit history and a short write-up from day one.

The same regulations allow NPTEL and institution-run online courses for credit, but the text reviewed contains no clause on online internships. Do not assume a self-directed or online backend internship will be recorded as credit. Get the department’s answer first.

For topic alignment, TCE publishes a B.E. CSE curriculum for 2024-25, which includes an internship component, and a B.Tech. IT syllabus for the 2022-onwards scheme. Use the one for your programme to see which database and web courses your schema and API work can support.

For placement-related questions, the Career Development Centre contact page lists placement@tce.edu and +91 452 2482240-2. Ask what backend skills recruiters have sought from your branch.

Checks before you start the API project

• Ask your department which regulation year applies to you, and which internship clause and credit rules cover your batch.
• Ask in writing whether a self-guided or online backend project can count toward the 6-week internship, and what proof is required.
• Ask who is on the faculty evaluation team for your department and what report format they expect.
• Find the internship component in your own programme’s syllabus PDF and note its semester and credits.
• Email the Career Development Centre to ask which Python or backend skills recruiters ask about for your branch.
• Save every reply as an email or signed note.

Packaging the project for reviewers

A README is part of the project. Include a one-paragraph description, the stack, setup steps, environment variables, how to run tests, and three example requests with sample responses. Add a schema diagram as an image, and list what you would build next. In an interview, being able to explain one design trade-off, such as why you stored money as integers, matters more than the number of features.

Tag a release at the end of your schedule and keep commits small and descriptively named. A history of 30 clear commits shows how you work, which a single “final version” commit cannot.

Moving up a level

• From Level 1 to 2: add a second related table and ownership checks.
• From Level 2 to 3: add migrations, PostgreSQL, token refresh and a coverage report.
• From Level 3 to 4: add Docker, a CI workflow that runs your tests on every push, and a deployed instance with a health-check endpoint.

Rebuild rather than extend when the design is wrong. A clean second attempt at the same project usually teaches more than patching the first.

Frequently Asked Questions

Which framework should I pick for a first Python API?

FastAPI is a good default if you like type hints and automatic docs. Flask suits those who want to learn the pieces individually. Django REST Framework suits those who want authentication and an ORM ready-made. Any of them can support all projects at Levels 1 to 3.

Do I need PostgreSQL for my first project?

No. SQLite is enough for Levels 1 and 2. Move to PostgreSQL when you want to practise migrations, transactions and stricter constraints, or when you plan to deploy.

How many tests are enough for a first Python API project?

For a first project, ten to fifteen meaningful tests are enough if they cover success, validation failure, authentication failure and ownership. Coverage percentage matters less than whether the risky paths are tested.

Should I use JWT or session authentication?

Either is acceptable. JWT suits stateless APIs and is common in tutorials. Sessions are simpler in Django. Pick one, understand expiry and storage of secrets, and explain your choice in the README.

Can I use the same project for my college mini-project?

That depends on your department’s rules, which this guide cannot confirm. Ask your project coordinator in writing before you start, and ask whether prior or parallel work needs disclosure.

Will an online internship give me academic credit?

CareerSwami’s programme provides a free offer letter and a free completion certificate after successful completion, but no academic credit is claimed. Whether your college records it in any way is a question for your department.

Should I deploy the API?

Deployment is optional at Levels 1 and 2 and recommended at Levels 3 and 4. A free-tier host plus a health-check endpoint and documented environment variables is enough to demonstrate it.

What if I get stuck on a bug for more than a day?

Reduce it to the smallest failing test, read the full traceback, and then ask a mentor or peer with that test and the error text. A reproducible failing test usually gets an answer quickly.

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