A merge tool that turns data into documents data into documents

What Is a Document Merge Tool?

A document merge tool takes two inputs — a template and a data source — and produces one finished document per record. The template defines the structure and design; the data source provides the values that vary per document. The merge engine combines them, producing a separate, personalized output for each row or record in the data. The result is a set of documents that are identical in format and distinct in content.

The Data Source

Any structured data source works with EZdoc's merge tool. CSV is the most common: flat, widely supported, easy to produce from any spreadsheet tool. Excel files work the same way. JSON is useful for developers who want to generate documents programmatically — submit it to an asynchronous template merge job, poll for completion, then download the finished output. In all cases, EZdoc reads the field names (column headers for CSVs, keys for JSON) and maps them to the template automatically.

The Template

Templates in EZdoc can be built from scratch by describing what you need, or created by uploading an existing document. Either way, the variable fields — the parts that change per record — are identified so EZdoc knows what to merge. A well-built template has sensible defaults for fields that might be missing in some records, so the output stays clean even when the data is incomplete.

Merge at Any Scale

The mechanical steps of a merge are the same whether you're generating 5 documents or 5,000. The setup is the same, the template is the same, the data format is the same. EZdoc renders the batch in parallel, so a larger run finishes proportionally faster than a sequential approach would. Volume is a plan limit question, not an architectural question — you're not changing how the merge works as you scale up.

When to Use the API

The file-upload workflow is ideal for periodic runs where you have a complete dataset ready: end-of-month billing, end-of-cohort certificates, a quarterly mailing. The API is the right choice when documents need to be generated dynamically — a new user signs up and gets a welcome letter, an order ships and a label is printed, a test is passed and a certificate is issued. The template stays the same in both cases; the API just provides the record data at the moment it's needed.