Replit Policy Guardrails

Overview

Policy enforcement for Replit-hosted applications. Replit's shared hosting model, public-by-default Repls, and resource limits require guardrails around secrets exposure, resource consumption, and deployment security.

Prerequisites

• Replit account with Deployments access
• Understanding of Replit's security model
• Awareness of Replit's Terms of Service

Instructions

Step 1: Prevent Secrets Exposure

Replit Repls are public by default. Secrets in code are visible to anyone.

# BAD: secrets in source code (visible in public Repl)
API_KEY = "sk-live-abc123"  # anyone can see this

# GOOD: use Replit Secrets (Environment Variables)
import os
API_KEY = os.environ.get("API_KEY")
if not API_KEY:
    raise RuntimeError("API_KEY not set in Replit Secrets")

# Validate secrets are properly configured on startup
REQUIRED_SECRETS = ["API_KEY", "DATABASE_URL", "JWT_SECRET"]
missing = [s for s in REQUIRED_SECRETS if not os.environ.get(s)]
if missing:
    raise RuntimeError(f"Missing required secrets: {missing}")

Step 2: Resource Usage Limits

Replit enforces CPU and memory limits. Guard against runaway processes.

import resource, signal

# Set memory limit (512MB)
resource.setrlimit(resource.RLIMIT_AS, (512 * 1024 * 1024, 512 * 1024 * 1024))  # 1024: 1 KB

# Set CPU time limit
def timeout_handler(signum, frame):
    raise TimeoutError("Request exceeded CPU time limit")

signal.signal(signal.SIGALRM, timeout_handler)

@app.route('/process')
def process_request():
    signal.alarm(30)  # 30 second max per request
    try:
        result = heavy_computation()
        return jsonify(result)
    except TimeoutError:
        return jsonify({"error": "Request timed out"}), 504  # HTTP 504 Gateway Timeout
    finally:
        signal.alarm(0)  # cancel alarm

Step 3: Deployment Visibility Controls

Ensure production Repls are not accidentally made public.

# Validate deployment configuration before deploy
def validate_deployment_config():
    checks = []
    # Check visibility
    if os.environ.get("REPL_SLUG"):
        # Running on Replit
        if not os.environ.get("REPL_DEPLOYMENT"):
            checks.append("WARNING: Running as Repl, not Deployment (may sleep)")
    # Check required env vars
    if os.environ.get("NODE_ENV") != "production":
        checks.append("WARNING: NODE_ENV not set to production")
    # Check HTTPS
    if not os.environ.get("REPL_DEPLOYMENT"):
        checks.append("INFO: Custom domain HTTPS managed by Replit Deployments")
    return checks

Step 4: Database Access Controls

Replit DB is accessible to anyone with the Repl URL if not properly secured.

from functools import wraps

def require_auth(f):
    @wraps(f)
    def decorated(*args, **kwargs):
        auth = request.headers.get('Authorization')
        if not auth or not verify_token(auth):
            return jsonify({"error": "Unauthorized"}), 401  # HTTP 401 Unauthorized
        return f(*args, **kwargs)
    return decorated

# Protect all database-accessing endpoints
@app.route('/api/data')
@require_auth
def get_data():
    return jsonify(db.get("data"))

Error Handling

Issue	Cause	Solution
Secrets leaked	Code is public by default	Use Replit Secrets, never hardcode
OOM kills	No memory limits	Set resource limits, monitor usage
Unauthorized DB access	No auth on endpoints	Add authentication middleware
Repl sleeping in prod	Using Repl instead of Deployment	Use Replit Deployments for production

Examples

Startup Security Check

def security_check():
    issues = []
    if not os.environ.get("JWT_SECRET"):
        issues.append("CRITICAL: JWT_SECRET not configured")
    if os.environ.get("DEBUG") == "true":
        issues.append("WARNING: Debug mode enabled in production")
    return {"secure": len(issues) == 0, "issues": issues}

Resources

• Replit Security
• Replit Deployments

Output

• Configuration files or code changes applied to the project
• Validation report confirming correct implementation
• Summary of changes made and their rationale