AWS Entity Resolution helps identify when different records refer to the same underlying entity. For example, a customer may appear in a CRM export, a billing database, and an online transaction dataset with different identifiers or contact details. The service compares selected attributes and assigns match identifiers to records determined to belong together. These identifiers provide a linkage layer for downstream processing without requiring applications to share a common source-system identifier.
A typical implementation starts with input data in Amazon S3 and table metadata in the AWS Glue Data Catalog. Engineers create a schema mapping that identifies the unique record identifier and maps source columns to supported attribute types, such as names, addresses, email addresses, and phone numbers. Schema mappings also specify which fields are passed through to output. Establish stable source identifiers and consistent field meanings before running workflows so that results remain traceable to their original records.
Matching workflows define how records are compared. Rule-based matching uses configurable, ordered rules that combine attributes, making it suitable for requirements such as matching on email address or on a combination of name and address. Machine learning-based matching identifies relationships that may be difficult to express with exact rules. Provider-based matching uses supported external identity providers and requires the appropriate provider access or subscription. The supported inputs, outputs, and configuration options differ by matching method.
Matching jobs process the configured input sources and write results to an S3 output location. Results contain match identifiers and method-specific information that downstream systems can use to interpret the links. These outputs are not automatically curated master records. Selecting an authoritative address, resolving conflicting names, and deciding whether to merge application records generally require separate business logic and, for ambiguous cases, manual review.
ID mapping workflows support a related but distinct operation: translating source identifiers into target identifiers using supported rule-based or provider-based methods. Depending on the configuration, this can involve datasets within an account or collaboration with another account. Design the required permissions and data-sharing arrangements before implementing cross-account workflows. Do not assume that a matching workflow and an ID mapping workflow have interchangeable configuration or output semantics.
Operational controls should include narrowly scoped IAM permissions, restricted S3 prefixes, and appropriate AWS KMS key policies. Validate regional availability, quotas, and matching-method constraints before committing to a design. Evaluate results against representative labeled records, measuring false matches and missed matches rather than relying only on job completion. Treat linkage outputs as sensitive derived data: a match does not establish consent or authorize a new use of personal information. Apply retention, access, and permitted-use policies throughout the pipeline.