act101 vs Langtail

A side-by-side comparison built from both listings. Blank cells mean the company has not given that detail; we never guess.

act101 compared with Langtail
Detail	act101	Langtail
What it does	Quality infrastructure for AI-written code with deterministic refactoring and a merge gate	Prompt management platform for building, testing, and deploying AI prompts collaboratively
Stage	Startup	Not given
Founded	2026	2023
Based in	US	CZ
Pricing model	Freemium	Not given
Pricing	Builder Edition: Free forever for personal, non-commercial, and open-source use. Engineering Edition: $29/month or $299/year (save 14%). Architecture Edition: $59/month or $599/year (save 15%). Elite Edition: $99/month or $999/year (save 16%). Enterprise: Custom pricing, contact sales. All editions	Free plan: $0/month with unlimited users, 2 prompts or assistants, 1,000 logs per month, 30 days data retention. Pro: $99/month + VAT for 1 user, 20 prompts or assistants, unlimited logs, 90 days data retention. Team: $499/month + VAT for 10 users, unlimited prompts or assistants, unlimited logs, 1
Key features	182 AST-aware refactor operations for code transformation 42 codebase analyzers for code analysis Support for 163 programming grammars Deterministic merge gate with signed receipts MCP server and CLI interfaces Cross-file import updates and automatic checkpointing 10 cross-language porting operations Instant undo for all operations ~88% token savings on query operations Native binary with zero dependencies and no supply chain risk	Spreadsheet-like interface for managing prompts with no coding required Natural language evaluation, pattern matching, and custom code testing Experiment with models and parameters to optimize prompts Data-driven insights from prompt performance and user interactions AI Firewall preventing prompt injections and DoS attacks Support for multiple LLM providers TypeScript SDK and OpenAPI support Self-hosting option for maximum security
What makes it different	Deterministic verdicts and signed receipts for every code change ensure reproducible quality gates Built by engineer with decades of production experience in correctness-critical domains	Prevents unpredictable LLM outputs through proper prompt management and testing Non-technical teams can manage prompts with intuitive spreadsheet interface Built-in AI Firewall for security and safety of AI outputs Works seamlessly with all major LLM providers
Community votes	0	0
DR (Domain Rating by Ahrefs)	27 no change since last check	29 no change since last check
Trust Flow (Majestic)	8	6
Citation Flow (Majestic)	31	34
Referring domains (Majestic)	182	275

6 details filled in for both companies.

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