In modern web applications, data is constantly moving in both directions:
- From frontend to backend (forms, logins, user input)
- From backend to frontend (profiles, dashboards, records)
A common question for developers and product teams is:
How do you securely send data between frontend and backend without over-engineering encryption?
This article explains the correct, industry-standard approach to securing data in both directions, why plain JSON over HTTPS is safe, and how regulations like HIPAA apply as an example.
Understanding frontend ↔ backend data flow
Every modern web application follows this pattern:
- A user enters data in the frontend
- The frontend sends data to the backend
- The backend processes and stores the data
- The backend sends a response back to the frontend
This applies to:
- SaaS platforms
- E-commerce websites
- Fintech applications
- Healthcare systems
- Enterprise dashboards
The key question is how this data is protected while moving across the network.
Frontend to backend: how to securely send user data
When the frontend sends data to the backend, it usually looks like this:
{
"email": "user@example.com",
"password": "••••••••"
}
Is this secure?
Yes — when sent over HTTPS.
Why HTTPS is enough
HTTPS uses TLS (Transport Layer Security) to encrypt:
- Request bodies
- Headers
- Cookies
- API payloads
This means:
- Data is encrypted before leaving the browser
- Attackers cannot read intercepted traffic
- Man-in-the-middle attacks are blocked
You do not need to:
- Encrypt data manually in JavaScript
- Hash emails on the frontend
- Implement custom cryptography
In fact, doing so often creates security risks.
Backend to frontend: how to securely return data
When the backend sends data back to the frontend, it often returns JSON:
{
"name": "Jane Smith",
"accountStatus": "Active"
}
Again, this is safe and secure when sent over HTTPS.
Important clarification
“Plain text JSON” does not mean unprotected data.
- The JSON is readable only after TLS decryption
- On the network, it is fully encrypted
- This is the standard used by banks, governments, and cloud providers
Encryption happens in transit, not in the payload
One of the biggest misconceptions in web security is the idea that JSON fields must be encrypted.
In reality:
- Encryption belongs at the transport layer
- HTTPS already encrypts everything in transit
- Application-level encryption is rarely required
This model is recommended by:
- Cloud security frameworks
- Enterprise architecture standards
- Regulatory bodies
What matters more than encryption
Across industries, breaches rarely happen because TLS was missing.
They happen because of access and exposure failures.
Security best practices that actually matter
1. Authentication
Ensure only logged-in users can send or receive data.
2. Authorization
Ensure users can only access data they are permitted to see.
3. Data minimization
Send only the data required — nothing extra.
4. Secure frontend handling
- Do not store sensitive data in
localStorage - Do not log real user data
- Do not cache sensitive responses
5. Secure backend controls
- Validate every request
- Log access events
- Rate-limit APIs
Regulatory example: HIPAA (healthcare)
Some industries have additional compliance requirements.
For example, in healthcare, HIPAA requires that patient data be:
- Protected from unauthorized access
- Encrypted in transit
- Accessed only by authorized users
HIPAA does not require:
- Encrypting JSON payloads
- Client-side encryption
- Custom frontend cryptography
Oversight in the U.S. is handled by the U.S. Department of Health and Human Services.
Similar principles exist in finance, insurance, and enterprise security standards.
Common mistakes to avoid
These mistakes cause most real-world security incidents:
- Using HTTP instead of HTTPS
- Sending sensitive data in URLs
- Storing data in browser storage
- Logging user data for debugging
- Over-fetching unnecessary fields
- Using third-party tools without proper safeguards
Avoiding these errors is far more important than adding extra encryption.
Best practice checklist: frontend ↔ backend security
✔ Enforce HTTPS everywhere
✔ Use TLS 1.2 or TLS 1.3
✔ Authenticate and authorize all requests
✔ Send minimal required data
✔ Disable caching for sensitive responses
✔ Avoid frontend storage of sensitive data
✔ Log backend access events
If these are in place, plain JSON in both directions is secure and compliant.
Final takeaway
Secure applications are not built by encrypting everything twice.
They are built by designing correct data flows.
Encrypt the connection.
Control access.
Minimize exposure.
Monitor usage.
This approach works for:
- Frontend to backend data transfer
- Backend to frontend responses
- Regulated and non-regulated industries alike
