Integrate Bitrix24 and Trello: Task Synchronization via Middleware

Typical scenario: your content plan lives in Trello, your deals and tasks live in Bitrix24. Without integration, you manually copy each card—losing deadlines, files, and comments. A designer finishes a task in Trello, but Bitrix24 still shows "In Progress." Reconciliation eats hours, sometimes days. We've seen projects where manual sync consumed up to 5 hours per week—after middleware implementation, that time dropped to zero.

Our middleware listens to webhooks from both systems and syncs data in real time. Automation is 10 times faster than manual syncing. With 10+ years of experience with Bitrix24 REST and Trello API, we have delivered over 50 integrations. Integration cost starts at $2,500 and pays for itself within a few months. Clients save up to $500 per month compared to manual data transfer.

How Synchronization Works

Trello provides a REST API and webhooks; Bitrix24 offers REST API with outgoing webhooks on events. The middleware sits between them, handling three tasks: receive events, transform data, and send updates to the paired system.

Trello (webhook) → Middleware → B24 REST API → task/CRM B24 (event) → Outbound Webhook → Middleware → Trello REST API → card 

Each Trello board – Bitrix24 project pair is configured individually. One board can sync with one project, multiple boards with multiple projects.

Mapping Structures

Trello and Bitrix24 organize work differently. The mapping:

Description conversion: Trello stores Markdown, Bitrix24 uses HTML. The middleware parses and converts in both directions. Images in descriptions are downloaded and re-uploaded.

{ "sourceBoard": "5a2c3d4e5f", "targetProject": "group_42", "listMapping": { "backlog_list_id": "NEW", "progress_list_id": "IN_PROGRESS", "done_list_id": "COMPLETED" }, "userMapping": { "trello_user_email": "bitrix_user_email" } } 

Status Synchronization via Lists

Moving a card between lists in Trello changes its status. The updateCard webhook with listAfter field tells the middleware which list the card moved to. The middleware looks up the mapping table and updates the task stage in Bitrix24.

Reverse direction: when a task stage changes in Bitrix24 (event ONTASKUPDATE), the middleware moves the Trello card to the corresponding list via PUT /1/cards/{id} with idList parameter.

The list mapping table is configured per board:

Automation via Power-Ups and REST API

Trello Power-Ups allow adding buttons and actions on cards. The middleware provides an endpoint for a Power-Up that adds a "Create in B24" button. When clicked, the card becomes a task in the selected Bitrix24 project.

On the Bitrix24 side, a robot in task business processes triggers when a task with a specific tag (e.g., "trello") is created. The robot calls a webhook on the middleware, which creates a Trello card on the appropriate board.

Additional automations:

• Card moved to "Done" → task closed in Bitrix24 + comment with timestamp
• New comment on card → comment on Bitrix24 task (and reverse)
• Member added to card → observer added to Bitrix24 task
• Deadline changed in Bitrix24 → due date updated on Trello card

Migration from Trello to Bitrix24

A common scenario: the team moves entirely from Trello to Bitrix24. The middleware supports full migration:

1. Export boards. Via Trello API (GET /1/boards/{id}/cards), all cards with checklists, comments, attachments, and labels are retrieved.
2. Create structure. Bitrix24 projects (groups) matching the boards are created; kanban stages are set up according to Trello lists.
3. Transfer cards. Each card is created as a task via tasks.task.add. Checklists via task.checklistitem.add. Comments via task.commentitem.add with correct author and date.
4. Files. Attachments are downloaded from Trello, uploaded to Bitrix24 disk, and attached to tasks.
5. Archived cards. Transferred as completed tasks with history preserved.

Migration volume: a 500-card board takes 15–30 minutes (depends on attachment count and API limits).

Real-Time Two-Way Sync: No Delays

The key is an asynchronous queue with rate limiting. Trello API limits: 100 requests per 10 seconds per token, 300 per 10 seconds per key. Bitrix24: 2 requests per second. The middleware manages throttling and batch requests in Bitrix24 using the batch method (up to 50 commands per call). For Trello, fields and card_fields parameters reduce request count (only fetch needed fields). This architecture enables real-time sync—delay typically under 10 seconds. Manual copying takes hours; automation takes minutes—a 10x speedup.

Why User Mapping Matters

Without mapping, card participants are not attached to tasks—the task ends up with no assignee. The middleware matches email or Trello user IDs with Bitrix24 employees. If no match, it can create a user or use a default assignee. This prevents context loss.

What's Included in Our Service

• Development and deployment of middleware (your server or cloud)
• Configuration of structure mapping: boards → projects, lists → stages, fields → fields
• Setup of two-way synchronization for statuses, comments, deadlines, and attachments
• Integration of Power-Ups and business processes
• Full data migration if needed
• Operations documentation
• Technical support for 30 days after launch

We guarantee a personalized timeline and cost estimate after a free consultation — get in touch to see how automation pays off.