January 30, 2025
Challenges of Manually Coding ETL Connectors for Application APIs

Whether a company builds ETL connectors in-house or relies on a third-party vendor, the challenges remain the same: it’s time-consuming, error-prone, and inefficient. Precog leverages AI to automate these repetitive tasks, delivering faster, more accurate results—exactly what AI is meant to do. Manually coding ETL (Extract, Transform, Load) connectors for application APIs is a daunting task that can drain resources, create inefficiencies, and introduce risks across data pipelines. Below is a detailed breakdown of the challenges involved.
Complexity of Application APIs
- Inconsistent API Structures: APIs often vary widely in how they expose data. They may use different protocols (e.g., REST, SOAP, GraphQL), data formats (e.g., JSON, XML, CSV), or levels of nesting, making each integration unique and time-consuming.
- Versioning and Deprecation: APIs evolve over time, with new versions introducing breaking changes and deprecated endpoints. Keeping connectors functional requires continuous monitoring and updates
- Poor Documentation: Many APIs lack clear or updated documentation, forcing developers to spend additional time testing endpoints and deciphering how to extract the necessary data.
Time-Intensive Development Process
- Custom Schema Mapping: Developers must manually map API response data to relational database structures, which is labor-intensive and prone to errors, especially for APIs with highly nested or complex data.
- Normalization: Converting semi-structured API responses into a normalized schema with primary keys and relationships is a tedious task that requires deep technical expertise.
- Edge Cases: APIs often contain irregularities or exceptions in their data, requiring developers to account for all possible scenarios to avoid data loss or corruption.
Scalability Issues
- Expanding API Ecosystems: As organizations adopt more applications, the number of APIs they need to integrate grows exponentially. Manually building and maintaining connectors for dozens or hundreds of APIs is unsustainable.
- One-Off Connectors: Each API requires a bespoke connector, meaning the process does not scale easily across new applications.
Data quality risks
- Sparsely Populated Fields: Developers often overlook fields with sparse or edge-case data, leading to incomplete datasets and missed insights.
- Typing Errors: Manually assigning data types increases the likelihood of mismatches or inaccuracies, which can cause downstream analysis errors.
- Relationship Mapping: Accurately identifying and linking data relationships in APIs with complex structures is challenging and error-prone.
Maintenance challenges
- Frequent API Updates: APIs frequently change, adding new fields, modifying structures, or deprecating features. Each update requires manual adjustments to the connector code, increasing maintenance overhead.
- Code Complexity: A manually built connector is often thousands of lines of custom code. This becomes increasingly difficult to manage, debug, and optimize as the codebase grows.
- Monitoring and Reliability: Without robust automation tools, detecting failures or changes in API behavior requires constant vigilance and manual intervention, delaying issue resolution.
Performance and optimization
- Handling Large Volumes of Data: APIs often return paginated or rate-limited data, requiring developers to implement efficient handling mechanisms. Improperly designed connectors can lead to slow performance, timeouts, or incomplete data extraction.
- Real-Time Data Needs: Building connectors that support real-time or near-real-time data pipelines is technically challenging and resource-intensive, requiring expertise in streaming architectures.
High cost of skilled resources
- Specialized Expertise: Building ETL connectors requires knowledge of APIs, data engineering, and database management. Recruiting and retaining developers with these skills is expensive.
- Resource Diversion: Time spent coding connectors diverts developers from higher-value tasks, such as building advanced analytics or machine learning models
Lack of standardization
- Inconsistent Practices: Different teams or developers may use varying standards for building connectors, leading to inconsistent and difficult-to-maintain codebases.
- Proprietary Features: Some APIs use proprietary or custom implementations that require tailored solutions, further complicating the process.
Security and compliance risks
- Sensitive Data Handling: APIs often expose sensitive data, such as PII (Personally Identifiable Information). Manually coding connectors requires strict adherence to data security and compliance standards like GDPR or HIPAA.
- Authentication Complexity: APIs use different authentication methods (e.g., OAuth, API keys, JWT tokens), requiring developers to implement robust and secure mechanisms for each integration.
Long development cycles
- Lengthy Testing and Debugging: Every connector must be thoroughly tested to ensure it handles all API responses, including edge cases, error codes, and rate limits. This can significantly delay deployment.
- Iterative Refinements: Initial implementations often require multiple iterations to refine performance, data quality, and compatibility with downstream systems.
How These Challenges Impact Organizations
Manually coding ETL connectors introduces bottlenecks that hinder agility and scalability:
- Slow Time-to-Value: It takes weeks or months to develop, test, and deploy a single connector, delaying critical insights.
- Increased Costs: The labor-intensive process consumes valuable resources, both in initial development and ongoing maintenance.
- Missed Opportunities: Incomplete or delayed data extraction prevents organizations from leveraging real-time insights, machine learning, or AI applications effectively.
