Why Postman Is Our Go‑To API Testing Tool and How We Use It

At WebRTC.ventures, quality testing is at the heart of everything we do. Robust API testing is the foundation of reliable performance, especially for WebRTC applications and AI integrations which depend on real-time performance and consistent connectivity. In our QA testing lab here in Panama City, Panama, we simulate real-world scenarios and network conditions to ensure APIs don’t just work, but perform reliably under pressure.

That’s why Postman is one of our favorite tools in the QA toolbox. We use Postman for automated API testing to validate and monitor APIs, ensuring our clients’ real-time communication solutions are secure, consistent, and well-validated.

More than half our QA team in Panama are ISTQB‑certified. That means we mix strong testing standards with the flexibility Postman gives us ensuring API tests are both structured and practical.

In this post, I’ll show you how Postman API testing became one of our favorite QA tools and how it strengthens our API testing process.

Postman: A Core Part of Our QA Process

From signaling to TURN servers, from session initiation to data channels, robust API testing is essential. That’s where Postman comes in.

We use Postman not just as a tool to send API calls, but as a central platform for organizing, automating, and validating our entire API testing process.

Here’s how we use it:

We group APIs by area (signaling, media, auth) and test them across dev, staging, and production.
We automate validations, set dynamic variables, and verify responses. This speeds up regression testing and reduces human error when repeating the same tests.
Postman works hand‑in‑hand with Newman (its CLI tool), letting us run automated test suites in our Jenkins and GitHub Actions pipelines. This keeps quality checks consistent and efficient.
Our QAs use Postman Monitors to regularly check key APIs in our staging environments, giving us early warnings if something drifts from expected behavior.
Using Postman Environments, we test the same API with different users, roles, or regions without rewriting requests every time.
Postman auto-generates API docs from our collections, so the whole team has one up-to-date place to check how things work.
Postman allows us to check secure connections (mTLS), by adding client certificates to make sure both sides trust each other.

Example: How We Test mTLS using Postman

Mutual TLS (mTLS) is used during the connection handshake between Postman and the API server. The handshake is the initial exchange where both systems introduce themselves, agree on secure communication, and build trust before sharing data.

With standard TLS (TLS), only the server proves its identity. mTLS adds an extra layer. Postman also presents a client certificate which the server verifies before allowing access. Configuring Postman Monitors with this certificate ensures that only trusted clients can connect, keeping the API secure.

For example, imagine a staging API that handles sensitive user data. We configure Postman with a client certificate and run a monitor. During the handshake, Postman presents the certificate, and the server verifies it. Only if the certificate is valid does the API respond. Any unauthorized client without the correct certificate is blocked.

In other words, mutual TLS (mTLS) works like a club where both sides must show ID:

The client (Postman) shows a certificate to prove it’s allowed in.
The server shows its certificate to prove it’s legit.

Step 1: Create a Client Certificate

Postman needs its own “ID card.”

Use OpenSSL (or similar) to generate:
- .crt → the certificate
- .key → the private key
- or .p12 → a bundle with both

Without this, Postman can’t even start the handshake.

Step 2: Map the Certificate in Postman

Tell Postman which certificate to use for your API:

Without mapping, Postman will knock but won’t get in.

Step 3: Keep SSL Verification ON

Step 4: Send the Request

Hit Send in Postman.

Success → 200 OK (or API response)
Fail → handshake error

Step 5: Confirm the Handshake

Open the Postman Console:

Look for:

That’s proof Postman showed its ID.

Step 6: Negative Tests (Break It on Purpose)

Try these to confirm the server blocks bad certs:

Remove certificate mapping → should fail
Use wrong or expired cert → should fail
Use cert without clientAuth → should fail

Step 7: Save Proof

Capture screenshots of:

Certificate mapping in Postman
Console showing Client certificate sent
A successful request
A failed request

Our Typical Postman Testing Flow

While each project is unique, our general testing flow follows a proven pattern:

Define API expectations with developers.
Set up environments.
Build modular Postman collections.
Writing assertions to validate responses, payload structures, and edge cases.
Chain requests for workflows
Running tests through Newman in our CI/CD pipelines for every build or deployment.
Scheduling ongoing API checks to maintain stability over time.

This process has been refined over countless projects, helping us maintain consistent quality and reduce post‑release surprises.

Why Postman API Testing Matters to Our Clients

Reliable APIs are the backbone of any WebRTC application. By using Postman in combination with our team’s expertise, we help ensure that our clients’ products launch smoothly, perform well, and stay reliable over time.

Our clients know that they’re not just getting a functional product, they’re getting the peace of mind that comes with rigorous testing, a dedicated QA lab, and a highly skilled team.

Ready to Bring Quality to Your WebRTC Project?

At WebRTC.ventures, we take pride in the precision and reliability of our QA testing and our deep experience with tools like Postman position us to handle even the most complex WebRTC and AI projects.

Reach out to WebRTC.ventures. Let’s build (and test) something great together!

Further Reading:

Postman: A Core Part of Our QA Process