Users are accidentally overwriting each other's changes because your app was not built for concurrent editing?
You want to add real-time collaboration to an existing tool but you're not sure how to handle conflicts without rebuilding everything?
Live Collaboration Software Development
RaftLabs builds real-time collaborative applications where multiple users edit the same document, canvas, or dataset simultaneously. We implement operational transformation or CRDT-based conflict resolution, presence indicators, cursor sharing, and the version history that makes collaboration safely reversible.
The technical complexity in collaborative software is not showing two users' edits -- it is deciding what happens when those edits conflict. We design the conflict resolution strategy first, based on your specific data model and user expectations, then build the system that enforces it reliably under concurrent load.
OT or CRDT conflict resolution designed for your specific data model
Presence indicators, cursor sharing, and user awareness features
Full version history with per-user attribution and undo/redo
Load-tested for concurrent editing sessions at your expected user count
RaftLabs builds live collaboration software using operational transformation and CRDT-based conflict resolution. We deliver multi-user document editors, collaborative canvases, and shared data entry tools with presence indicators, cursor sharing, and full version history -- on fixed-cost engagements.
Most applications are built for one user at a time. Adding a second user who edits simultaneously is not a configuration change -- it requires a fundamentally different approach to how state is stored, transmitted, and merged. When two users change the same field at the same moment, the system needs a mathematically sound rule for what the result should be. Without that, you get silent data loss, last-write-wins overwrites, or state divergence that is invisible until someone notices their work has disappeared.
RaftLabs builds the synchronisation layer, conflict resolution logic, and real-time communication infrastructure that makes collaborative editing reliable. We have implemented both OT and CRDT-based systems for document editors, shared canvases, and multi-user data entry tools -- and we start every engagement by defining the conflict resolution strategy before writing any code, because that decision shapes everything else.
What we build
Collaborative document editing
Real-time co-editing for rich text documents, structured forms, and mixed-content pages. We implement the synchronisation layer, the OT or CRDT conflict resolution engine, and the WebSocket event protocol that keeps every user's view consistent. Character-level merging for text fields, field-level conflict handling for structured data, and a clean operational log that makes version history possible.
Real-time canvas and whiteboard
Multi-user canvas applications where users add, move, resize, and style elements simultaneously. We handle the coordinate system consistency, the z-order conflict resolution when users manipulate the same layer, and the object locking patterns that prevent frustrating simultaneous-selection conflicts. Drawing tools, shape libraries, and annotation layers with full undo/redo per user.
Multiplayer form and data entry
Shared spreadsheet-style interfaces and multi-user form workflows where different users fill in different fields concurrently. We implement field-level locking or last-write-wins with attribution depending on the data sensitivity, and build the real-time indicators that show which fields another user is currently editing so your team avoids collisions before they happen.
Presence and cursor sharing
User awareness features that show who is in a document, where their cursor or selection is, and what they are actively editing. Named cursor overlays, avatar stacks, active-section highlights, and typing indicators -- the features that make users feel like they are working in the same room rather than on separate copies of the same file.
Conflict resolution with OT and CRDTs
We implement the mathematical conflict resolution layer that determines what happens when two edits collide. Operational Transformation for linear text documents with a central authority, CRDT data structures for use cases that require offline editing or peer-to-peer synchronisation. We document the chosen approach and its edge cases so your team understands the guarantees the system provides.
Version history and undo/redo
Operation-log-based version history with per-user attribution so you can see exactly who changed what and when. Point-in-time restore, named snapshots, and per-user undo/redo that does not affect other users' sessions. The audit trail is stored in a queryable format so your application can surface change history in whatever UI your users expect.
Adding collaboration to an existing application?
We can assess your current data model and state management approach and tell you what a collaboration layer would require -- before you commit to building it. Most scoping sessions take two hours.
Related real-time development services
Real-Time App Development -- overview of our full real-time development practice
WebSocket Development -- the WebSocket infrastructure that powers live collaboration
Real-Time Dashboard Development -- live operational dashboards for teams monitoring shared data
Event-Driven Architecture -- event-driven backends for systems with complex multi-user workflows
Related services
Custom Software Development -- web applications with collaboration features built into the full product
SaaS Development -- SaaS products with collaborative editing as a core differentiating feature
Frequently asked questions
Operational Transformation (OT) and Conflict-free Replicated Data Types (CRDTs) are two different mathematical approaches to the same problem: how do you merge concurrent edits without losing data or creating inconsistent state? OT transforms incoming operations based on what has already been applied locally -- it is well-suited to linear text documents and has been production-proven in tools like Google Docs. CRDTs are data structures designed so that any merge order produces the same result -- they handle network partitions and offline editing more gracefully and are better suited to non-linear data structures like trees, graphs, and sets. We choose based on your data model, your offline requirements, and how much operational complexity your team is willing to manage long-term.
The right answer depends on the data type and user expectations. For rich text, OT or CRDT-based merging preserves both users' changes at the character level -- the same approach Google Docs uses. For structured fields like a price or a status, last-write-wins with a visible edit history is usually the right tradeoff because merging structured data automatically produces results users find confusing. We design the conflict resolution strategy field by field during scoping, so users never encounter silent data loss or unexpected merged values.
At minimum: a WebSocket server for low-latency bidirectional communication, a persistence layer that stores the current document state and operation history, and a synchronisation service that applies and broadcasts operations in the correct order. For larger deployments, you also need a distributed operation log so that the synchronisation service can scale horizontally. We size and document the infrastructure as part of the engagement and provide the deployment configuration your team needs to operate it.
A focused collaboration feature -- real-time co-editing for a single document type with presence and basic version history -- typically runs $30,000 to $80,000. A full collaborative platform with multiple document types, advanced conflict resolution, detailed version history, permissions, and comment threading ranges from $80,000 to $200,000. We provide a fixed-cost quote after a scoping session where we review your data model and define the exact conflict resolution strategy.