Google Address Autocomplete

A REDCap External Module that adds Google Maps address autocomplete to survey and data entry forms.

As a participant types into the address field, Google Places offers predictions. Choosing one splits the address into whichever REDCap fields you have mapped — street number, street, city, state, postcode, country, latitude/longitude and place name — and stores the full formatted address in the original field.

A project can configure several independent address field sets: the participant's home address on one instrument, their GP practice address on another.

Single-file PHP module. Nothing to build, no dependencies to install.

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Requirements

REDCap 14.6.4+	The module declares External Modules framework version 16; REDCap will not enable it on an older release. LTS 15.0.9+ carries framework 16.
HTTPS	Google's geolocation and Places APIs will not run over plain HTTP.
A Google Maps API key	With Places API (New) enabled, plus a billing account. Google no longer enables the legacy Places API for newly issued keys, and this module has no legacy fallback.

Quick start

1. Copy Google_Address_Autocomplete.php and config.json into redcap/modules/<module_name>_v<version>/. Don't rename that directory — REDCap derives the module prefix and version from it.

2. Enable the module in Control Center → External Modules, then enable it on your project.

3. Configure it on the project (External Modules → Configure) and set:

   • Google API Key — your Maps Platform key
   • Autocomplete Field — the text field the search box attaches to
   • at least one destination field, e.g. Street Field and City Field

4. Name the instrument under Instrument(s) this set applies to, so nothing is emitted on unrelated forms.

5. Hard-refresh the form (Ctrl+F5) and start typing an address.

Not working? Go straight to Troubleshooting.

Before going live, work through Security and privacy. The API key is visible in the page source — inherent to the client-side Maps API — and the module sends participant-typed text to Google, which is a disclosure you may need to declare.

Documentation

Page	Read it when
Installation	Deploying the module, or a change you deployed hasn't taken effect
Settings	Configuring a project — every setting, and what it does
Fields and address field sets	Choosing which REDCap fields to map, or capturing more than one address
How it behaves on the form	You want to know what the participant sees — and how unit/apartment numbers are recovered
Security and privacy	Before going live. Locking down the API key, and the disclosure to participants
Troubleshooting	Something isn't working
Execution flow	Tracing a page render end to end, with a diagram per phase
Development	Changing the code — test harnesses, limits, docs layout

About this project

Parts of this module — code, review and documentation — were produced with assistance from Claude (Anthropic), used via Claude Code. Everything was reviewed by the maintainer before release, and behaviour is verified against a live REDCap instance. Responsibility for the code rests with the maintainer, not the tool.

Changelog: CHANGELOG.md. Note that REDCap reads the deployed version from the module directory name (_v<version>), not from config.json — so a release means renaming the deployment directory and tagging the commit to match.

License: MIT — see LICENSE. Copyright © 2026 John Barrett.