How RESTK Encrypts Your API Data: End-to-End Encrypted Security by Design

Every API tool stores sensitive data — bearer tokens, API keys, OAuth credentials, authentication headers, request bodies with private payloads, environment variables with database connection strings. Most tools store this in plaintext on their servers. If their database is breached, your secrets are exposed.

RESTK takes a fundamentally different approach.

The Problem: Plaintext Is the Default

When you use a typical cloud-based API testing tool, your bearer tokens, OAuth client secrets, and request payloads travel to the vendor's servers in a form that the vendor can read. They may encrypt it at rest, but the vendor's infrastructure can technically access the plaintext. Their employees may have access for support and debugging. Their cloud provider's staff has physical access to the hardware.

This is not an abstract risk. API tooling companies have faced real scrutiny over how their cloud sync features handle sensitive data. Teams have discovered their API keys and authentication tokens stored in plaintext on vendor servers — accessible to anyone with admin access.

Even if you trust the vendor, a database breach exposes everything. A single compromised server means every user's secrets are out in the open.

We decided this tradeoff was unacceptable.

Our Approach: Client-Side Encryption

When you save an API request in RESTK, your sensitive data is encrypted on your device before it ever reaches our servers. Our server receives, stores, and syncs encrypted data — it never sees the plaintext values.

This is not a marketing claim. It is an architectural guarantee. Our server literally does not have the code paths to decrypt your data during normal operations.

Here is what a typical save looks like:

1. You create an API request with a Bearer token and a JSON body
2. Your RESTK app fetches your workspace encryption key (delivered securely — more on that below)
3. Your app encrypts the Bearer token, header values, and body content locally on your device
4. The encrypted data is sent to our server via HTTPS
5. Our server stores the encrypted values in the database
6. At no point does our server see your Bearer token or body content in plaintext

When a teammate opens the same request on their device, the process reverses — their app pulls encrypted blobs from the server and decrypts everything locally.

What Gets Encrypted

Not everything needs encryption. Request names and HTTP methods need to be searchable and displayable in the UI. Here is the full picture:

Best practice: Never hardcode secrets directly in URLs. Use environment variables for tokens, API keys, and other sensitive URL segments — those variable values are encrypted.

Three-Layer Key Architecture

A single encryption key would be a single point of failure. RESTK uses a layered key system where no single key can access your data.

Layer 1: Workspace Keys

Every workspace gets its own unique encryption key, generated using a cryptographically secure random number generator. If you have five workspaces, there are five independent keys. Compromising one workspace key has zero impact on the others.

The algorithm is AES-256-GCM — Advanced Encryption Standard with 256-bit keys in Galois/Counter Mode. This is an authenticated encryption algorithm that provides both confidentiality (data cannot be read) and integrity (data cannot be tampered with without detection). It is the same standard used by governments and financial institutions for classified data.

Layer 2: Key Protection at Rest

Your workspace keys themselves are encrypted before being stored in our database. Even if an attacker gained full database access, they would find encrypted keys protecting encrypted data — two barriers, not one.

Layer 3: Device-Bound Key Delivery

When your device needs a workspace key, it must be delivered securely from our key management system. This is done using a one-time transport key that is:

• Derived from your active session and a device-specific secret
• Unique to each key request
• Never stored anywhere — it exists only for the duration of the key exchange
• Bound to your specific device and session — intercepting it on one device gives zero access from another

The device secret is generated locally when you first set up RESTK. It never leaves your device in its original form. We receive only a one-way cryptographic fingerprint during key exchange operations.

Key Versioning and Rotation

Even the strongest key becomes a liability if used indefinitely. Key rotation limits the blast radius of a potential compromise — if a key is ever exposed, only data encrypted during that key's active period is affected.

RESTK supports key versioning with the ability to rotate workspace keys:

• New data is encrypted with the latest key version
• Old data remains readable because previous key versions are securely retained
• Each encrypted value carries a version marker so the correct key is always used for decryption
• The transition is seamless — you never need to re-encrypt existing data or take any manual action
• Team members receive updated keys automatically during their next sync

What do you see? Nothing. Key rotation is invisible. Your data remains accessible and encrypted without any interruption.

End-to-End Encrypted Server

"End-to-end encrypted" means our servers have no ability to read your encrypted data during normal operation. Here is what that looks like in practice:

On-Device Protection

Server-side encryption protects your data on our infrastructure. But RESTK also applies multiple layers of protection on your device itself.

Encrypted Local Database

Your workspace data is stored locally in an encrypted database. The encryption key is derived from your identity and bound to your device — the database file is unreadable if copied to another machine or accessed outside the app.

macOS Keychain Integration

Sensitive credentials — your session tokens, authentication data, and stored passwords — are kept in macOS Keychain. These credentials are accessible only when your device is unlocked and only by the RESTK app. They cannot be read by other applications.

Field-Level Encryption

Rather than encrypting your entire database as a single blob, RESTK encrypts each sensitive field independently. Your Bearer token, each header value, each parameter value, and your request body are each encrypted as separate values with their own initialization vectors. This means:

• Decrypting one field does not expose any other field
• Each field can be encrypted with a different key version during key rotation
• The app only decrypts the specific fields it needs to display at any given moment

Forward Secrecy on Sign-Out

When you sign out of RESTK, the app regenerates your device secret. This means that even if your previous session credentials were somehow captured, they cannot be used to derive transport keys or access workspace encryption keys. Each sign-in session is cryptographically independent.

Log Sanitization

RESTK automatically sanitizes all application logs to prevent accidental exposure of sensitive data:

• Tokens and API keys are masked before being written to any log
• Authentication headers (Bearer, Basic, JWT) are redacted to show only a safe prefix
• Personal information (email addresses, user IDs) is partially masked
• Sensitive patterns (credit card numbers, phone numbers) are detected and redacted automatically

AI Assistant Safeguards

RESTK's AI assistant integration (via MCP) requires your explicit approval for every action that modifies your data. The AI cannot silently read, modify, or delete your data. Every write operation triggers a confirmation prompt. Only data you have explicitly marked as shared with AI is visible to assistants.

Team Encryption

Everything described above applies equally to shared team workspaces. When your team collaborates on API development, each member's device independently encrypts and decrypts data. The server moves encrypted data between devices without ever accessing the plaintext.

Per-Workspace Key Isolation

Organizations typically have multiple workspaces. Each workspace has completely independent encryption keys:

If an attacker somehow compromised Key B (Staging), they would have zero access to Production APIs or Internal Tools. Workspace key isolation is absolute.

Member Onboarding and Offboarding

When a new member joins a workspace, their device automatically generates a device secret and receives workspace keys through secure, device-bound transport. No manual key exchange, no shared passwords, no setup scripts.

When a member is removed, they immediately lose API access and can no longer receive workspace keys. As a recommended security practice, rotate the actual credentials (API keys, tokens) the removed member had access to — this is standard security hygiene regardless of the encryption model.

Compliance Support

RESTK's encryption architecture supports compliance with several common frameworks:

Important note: RESTK's encryption addresses the technical controls for these frameworks. Full compliance depends on your organization's broader security program, policies, and procedures. We are not claiming certification — we are saying our architecture provides the technical encryption controls these frameworks require.

Learn More

For a detailed technical reference covering every aspect of our encryption architecture — including the full FAQ, threat model, and team setup checklist — see our Security & Encryption documentation.

Your API secrets are yours. We built RESTK so that even we cannot read them.

Have questions about our security architecture? Reach out at [email protected].