/
Data engineering

What makes a good JSON? Which rules to follow for my data?

A comprehensive guide to selecting, formatting, and understanding JSON keys for creating well-organized data structures while ensuring compatibility with parsers.
Blog post featured image

What makes a good JSON? Which rules to follow for my data?

Why JSON Key Formatting Can Make or Break Your Data Integration

In today's data-driven business environment, JSON (JavaScript Object Notation) serves as a critical format for data exchange between systems. Understanding JSON key constraints is essential for organizations implementing data integration solutions, as improper key formatting can lead to sync failures, data loss, and costly integration delays.

Key Takeaways

  • Standard characters: Use alphanumeric characters, underscores, and hyphens to ensure maximum compatibility.
  • Formatting: Always wrap keys in double quotes and remember that keys are case-sensitive.
  • Naming conventions: Apply consistent camelCase or snake_case to reduce mapping errors by up to 50%.
  • Avoid digit prefixes: Never start a key with a number, as many downstream systems will reject it.
  • Validation: Automated validation helps prevent integration delays and costly manual engineering fixes.

When implementing data synchronization between systems like Salesforce and PostgreSQL, properly formatted JSON keys ensure seamless data flow and prevent integration errors that can disrupt business operations. For organizations syncing millions of records daily between CRMs, databases, and data warehouses, understanding JSON key constraints is critical. At Stacksync, we've seen companies lose hours troubleshooting integration failures caused by simple key formatting issues problems that could have been prevented with proper validation upfront.

Allowed Characters in JSON Keys

Category Allowed characters Why it matters
Alphabetic Lowercase and uppercase letters Ensures universal parsing across APIs and languages
Numeric Digits from 0 to 9 Safe for identifiers and counters in schemas
Separator Underscore character Common convention for readable field names
Separator Hyphen character Supported across most platforms and tooling
Unicode support Technically allowed but discouraged Often breaks parsers and cross-system compatibility
Enterprise impact Cross-platform data sync Prevents failures in CRM, ERP, and warehouse pipelines

Key Takeaways

Restricting JSON keys to standard characters improves reliability across integrated systems.

Non-standard characters frequently cause parsing errors and hard-to-debug failures.

Following these rules reduces risk and avoids costly fixes when syncing data at scale.


When configuring data synchronization workflows, your JSON keys should use these standard characters to ensure compatibility across all systems:

  1. Letters (both lowercase and uppercase): a-z, A-Z

  2. Digits: 0-9

  3. Underscore: _

  4. Hyphen: -

While JSON technically supports any Unicode character in keys, Stacksync strongly recommends limiting keys to these standard characters. In our experience supporting thousands of enterprise integrations, non-standard characters frequently cause parsing failures and compatibility issues across different systems and programming languages.

For companies synchronizing data between platforms like Salesforce, NetSuite, and Snowflake, adhering to these character constraints prevents integration failures that can halt critical business processes and require expensive engineering intervention to resolve.

JSON Key Rules

When implementing real-time data synchronization, follow these critical JSON key requirements to prevent sync failures and ensure data consistency across your systems:

  • Keys must be enclosed in double quotation marks (" "). Example: "namecustomer_id": "AliceCUST-12345" or "order_total": 1250.00

  • Keys are case-sensitive, so "key" and "Key" are treated as distinct. Example:

  • Avoid starting keys with digits. While JSON parsers may accept this, many downstream systems and programming languages will reject digit-prefixed keys, causing integration failures. Always begin keys with a letter or underscore to ensure compatibility across your entire data stack.

{
  "key": "value1",
  "Key": "value2"
}

Valid JSON Key Examples

Here are some examples of valid JSON keys:

{
  "username": "johndoe",
  "user_id": 123,
  "user-name": "johnny",
  "_internalFlag": true,
  "email1": "[email protected]"
}

These key formats ensure seamless synchronization across all platforms in your data ecosystem. Stacksync's validation engine automatically checks for these patterns during sync configuration, preventing formatting issues before they can disrupt your data flows.

Best Practices for Naming JSON Keys

For organizations managing real-time synchronization of millions of records, consistent JSON key naming is critical. Benefits include:

  • Reduced Errors: 35-50% fewer data mapping errors.

  • Faster Integration: Standardized conventions streamline cross-system workflows.

  • Choose either camelCase or snake_case and apply it consistently across all integrated systems. In our experience with enterprise customers, inconsistent naming conventions are a leading cause of field mapping errors during CRM-to-database synchronization.

  • Never use spaces or special characters in keys. These characters cause parsing failures in many systems and will break synchronization between platforms like Salesforce and your operational databases.

  • Use descriptive keys that clearly indicate the data type and purpose, such as customer_lifetime_value rather than clv or customer_lifetime_value_calculated_from_all_historical_purchases. Keys between 2-4 words typically provide the best balance of clarity and efficiency in high-volume sync operations.

  • Use standard abbreviated keys like id, uid, or sku only for universally recognized identifiers. When syncing between systems with different naming conventions—such as Salesforce's AccountId and your database's customer_id—Stacksync's field mapping interface allows you to maintain each system's native conventions while ensuring accurate data flow.

Implement JSON Best Practices in Your Data Workflows

Properly formatted JSON keys are fundamental to reliable data synchronization across your business systems. By following these guidelines, you'll prevent integration failures and ensure consistent data flow between your CRM, databases, and data warehouses.

While JSON key rules are straightforward, implementing them consistently across complex, multi-system integrations requires careful planning and validation. Stacksync automates this validation process, checking key formats during sync configuration and alerting you to potential issues before they impact your data flows.

When implementing data synchronization workflows, stick to letters, numbers, underscores, and hyphens in your JSON keys, and always use double quotes. Ready to see how Stacksync simplifies data integration while automatically validating your JSON structures? Start a free trial today and experience real-time, bi-directional synchronization between your CRM, databases, and business systems—with built-in validation to prevent formatting issues before they occur.

Ready to see a real-time data integration platform in action? Book a demo with real engineers and discover how Stacksync brings together two-way sync, workflow automation, EDI, managed event queues, and built-in monitoring to keep your CRM, ERP, and databases aligned in real time without batch jobs or brittle integrations.
→  FAQS
What are the basic rules for JSON data structure?
JSON data uses key-value pairs separated by commas, enclosed in curly braces {}. Keys must be strings in double quotes, and the order of pairs doesn't matter.
Which characters can I use in JSON keys?
JSON keys accept letters (a-z, A-Z), digits (0-9), underscores (_), and hyphens (-). While any Unicode character technically works, sticking to these ensures better parser compatibility.
What format requirements must JSON properties follow?
Each JSON property takes the form "key": value with keys as double-quoted string literals. Objects and arrays cannot have trailing commas, and methods or functions are not valid data types.
What makes JSON formatting correct?
Valid JSON uses name/value pairs separated by commas, with objects wrapped in curly brackets {}. An empty object appears as {}, and all strings require double quotes.
Can JSON contain comments or whitespace?
JSON does not support comments in its specification. However, whitespace (spaces, tabs, newlines) between structural elements is allowed and ignored by parsers, making your JSON more readable without affecting validity.

Syncing data at scale
across all industries.

a blue checkmark icon
14-day trial
a blue checkmark icon
Two-way, Real-time sync
a blue checkmark icon
Workflow automation
a blue checkmark icon
White-glove onboarding
“We’ve been using Stacksync across 4 different projects and can’t imagine working without it.”

Alex Marinov

VP Technology, Acertus Delivers
Vehicle logistics powered by technology