Swyx

Enables multiple users to simultaneously edit and test AI prompts with instant execution results displayed in a shared workspace. Uses WebSocket-based real-time synchronization to propagate prompt changes across connected clients, with a backend execution engine that routes prompts to multiple LLM providers (OpenAI, Anthropic, etc.) and streams results back to all collaborators. Implements operational transformation or CRDT-style conflict resolution to handle concurrent edits without blocking.

Abstracts prompt execution across multiple LLM providers (OpenAI, Anthropic, Cohere, local models) with intelligent routing based on cost, latency, and model capability constraints. Routes requests through a provider abstraction layer that normalizes API differences, handles rate limiting, and selects the optimal provider based on user-defined policies (e.g., 'use GPT-4 for complex reasoning, Claude for long context'). Likely implements a provider registry pattern with pluggable adapters for each LLM API.

Maintains a version history of prompts with the ability to run A/B tests comparing different versions against the same inputs. Tracks execution metrics (latency, cost, token usage) and output quality metrics (user ratings, automated evaluations) for each variant, then computes statistical significance to determine which prompt version performs better. Likely uses a database to store prompt versions, execution logs, and evaluation results, with a statistical analysis engine to compute p-values or confidence intervals.

Allows users to define prompt templates with placeholders for dynamic variables (e.g., {{user_input}}, {{context}}, {{model_name}}) that are injected at execution time. Supports variable validation rules (e.g., 'context must be < 2000 tokens', 'user_input must not be empty') and type coercion (e.g., converting numbers to text). Likely uses a templating engine (Handlebars, Jinja2-style) with a validation schema layer to ensure injected variables meet constraints before execution.

Records every prompt execution with full context (input, output, model used, provider, latency, token counts, cost) in an immutable audit log. Provides search and filtering across execution history (by date, model, cost range, output quality) and generates cost reports aggregated by time period, model, or prompt. Likely stores logs in a database with indexing for fast retrieval and includes a UI for browsing and exporting logs.

Allows users to define custom evaluation metrics (e.g., 'response contains all required fields', 'sentiment is positive', 'length < 500 tokens') and automatically score prompt outputs against these metrics. Supports both rule-based evaluations (regex, token counting, field extraction) and LLM-based evaluations (using a separate LLM to judge quality). Stores evaluation results alongside execution logs for trend analysis and comparison across prompt versions.

Enables users to share prompts with team members via links or direct invitations, with granular access control (view-only, edit, admin). Tracks who modified a prompt and when, providing a change history with diffs. Supports commenting on prompts for asynchronous feedback and discussion. Likely uses a permission model (RBAC or similar) with a database to track ownership, access grants, and change history.

Maintains a searchable library of prompts with metadata (tags, description, author, creation date) and supports both keyword search and semantic search (finding similar prompts based on embedding similarity). Allows users to organize prompts into collections or categories and discover prompts by browsing or searching. Likely uses a vector database (Pinecone, Weaviate, or similar) to enable semantic search across prompt descriptions or content.