Android: Autofill custom fields in Bitwarden app (AutofillService & Accessibility)

[gryphon2411]

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✅ Code Contribution Proposal

Code Contribution Proposal

Hello Bitwarden team, and thank you for the great work and welcoming contributions.

On Android, the Bitwarden app’s Autofill/Accessibility flows fill username and password, but not custom fields from the same item. On desktop (browser extensions), custom fields fill perfectly. I’d love to contribute code to bring Android closer to desktop parity for common cases.

Feature request reference
Community FR: https://community.bitwarden.com/t/android-please-add-support-for-autofilling-custom-fields-in-the-bitwarden-app/89621

Motivation
Many sites ask for a third value (company/employee ID, PIN, account number). Today this means copy/paste on mobile, which is slower and error-prone. Adding custom-field autofill on Android would make everyday logins smoother and more consistent.

Scope (v1, intentionally modest)

• Support Text and Linked custom fields when target inputs are discoverable via Android’s Autofill framework.
• Browsers: Firefox for Android and Chromium-based (Chrome/Brave).
• Respect existing URI matching, vault lock, and security prompts.
• Not in v1: tricky flows where fields expose no useful identifiers (e.g., heavy iframes/shadow DOM). Happy to iterate later.

High-level approach

1. When building a FillResponse, in addition to user/pass, look at the item’s custom fields.
2. For each custom field, find a matching view in the page AssistStructure (e.g., idEntry, autofillHints, associated label/hint).
3. Add an AutofillValue for matches using conservative, normalized matching (case-insensitive; handle spaces/underscores).
4. Support Linked fields (e.g., linked to Username) using the resolved value from the item.
5. Keep behavior safe-by-default and opt for precision over breadth to avoid misfills.

Testing plan

• Manual repro: https://c.timewatch.co.il/punch/punch.php → tap English → login (requires an extra field).
• Instrumentation: simple WebView page with three inputs (user/pass/extra) whose ids/names match custom-field names; verify FillResponse includes all three.
• Unit tests: matching helper (normalization, no-match → no-fill).

Security & privacy

• No changes to lock prompts or overlay behavior.
• Only fill when domain/URI rules pass.
• No additional logging of field contents.

Environment (for current repro)

• Device: OnePlus 8T
• OS: OxygenOS 14 (Android 14)
• Browser: Firefox for Android:

143.0.3 (Build #2016117407), d4dc6995f3ff9fce253c5ec54fc509e5046e49c9
GV: 143.0.3-20250929153833
AS: 143.0
OS: Android 14

• Bitwarden Android app:

© Bitwarden Inc. 2015-2025

Version: 2025.9.0 (20692)
📱 OnePlus KB2003 🤖 14@34 📦 prod
🧱 commit: bitwarden/android/release/2025.9-rc34@2bd4834b14d1e199aaa8a9ee4f0db812c27dba53
💻 build source: bitwarden/android/actions/runs/17498992515/attempts/1
🦀 SDK: 1.0.0-2887-7b5d9db2
🌩 Server: 2025.9.2 @ US

• Server: Bitwarden Cloud (default)

Questions for maintainers (happy to follow your guidance)

• Preferred ordering among idEntry, autofillHints, label text, and placeholders?
• Any existing helpers you’d like me to extend?
• Is a small settings flag or staged rollout desirable for v1?

Next steps
If this direction seems reasonable, I’ll open a PR from a fork, sign the CLA, and keep the change narrowly scoped. I’m very open to feedback and am happy to adjust the plan to match project priorities.

Thanks again for considering! 🙏

[github-actions[bot]]

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