LimeSurvey

LimeSurvey is a powerful open-source survey platform trusted by over 60,000 organizations across 160+ countries — from academic institutions and government agencies to enterprises and nonprofits. It solves the fundamental limitations of proprietary tools like SurveyMonkey, Typeform, and Google Forms by giving you complete control over your data, infrastructure, and survey experience without usage caps, vendor lock-in, or recurring per-response fees.

The platform supports self-hosted deployment on any PHP-ready web server alongside an optional managed SaaS tier, making it accessible whether you need data sovereignty or just want to skip the operational overhead. With 30+ question types, 900+ pre-built templates, and a real-time expression engine that evaluates conditional logic across questions, emails, and quota calculations, LimeSurvey handles research workflows that simpler tools can’t accommodate.

Designed for both administrators and end-users, LimeSurvey ships with a plugin architecture that enables deep customization without touching core code, multilingual survey support with AI-assisted translation, WCAG 2.0 accessibility compliance, and enterprise integrations including SAML, LDAP, and a comprehensive XML-RPC/JSON-RPC RemoteControl API for programmatic control.

Built in PHP with a Yii-based backend and a Bootstrap 5 frontend, LimeSurvey has maintained backward compatibility for over 20 years while steadily modernizing its stack — a testament to the project’s commitment to long-term stability for organizations that depend on it for critical data collection.

What You Get

• Unlimited surveys and questions - Create as many surveys and questions as needed without usage caps, per-response fees, or tiered restrictions on any self-hosted instance.
• 30+ question types with 900+ templates - Multiple choice, matrix, slider, ranking, file upload, date/time, and more, plus pre-built templates for market research, NPS, academic studies, and HR evaluations to accelerate survey creation.
• Real-time conditional logic and question branching - A dedicated expression engine dynamically shows or hides questions, sends tailored emails, and applies quota rules based on respondent answers using a unified syntax evaluated in real time.
• Multilingual surveys with 80+ language support - Build and manage surveys in multiple languages simultaneously with AI-assisted translation, locale-specific formatting, and per-language label sets.
• Custom branding and full CSS/JS injection - Apply custom fonts, colors, logos, and inject arbitrary JavaScript or CSS to match your organization’s brand identity or extend survey behavior.
• RemoteControl API via XML-RPC and JSON-RPC - Programmatically create surveys, manage participants, retrieve results, and trigger exports through a comprehensive API with SDKs for multiple languages.
• GDPR compliance and data anonymization tools - Built-in SSL encryption, IP anonymization, token-based access control, and response anonymization options ensure legal compliance across jurisdictions.
• Plugin system for extensibility without core modifications - An event-driven PluginManager lets you add question types, authentication providers, export formats, and admin UI panels without touching core source files.
• SAML, LDAP, and SURFconext integration - Enterprise authentication integrations allow single sign-on and centralized user management for large organizations and academic institutions.
• Closed access and token-based surveys - Distribute surveys via personal invitation links, restrict access with tokens, and track individual response status while maintaining data anonymity.
• Advanced statistics dashboard and multi-format export - Analyze responses with built-in charts and summary statistics, then export to CSV, Excel, SPSS, R, STATA, and PDF for deeper analysis.
• Two-factor authentication and fine-grained permissions - Secure admin access with 2FA and assign role-based permissions to survey administrators, group managers, and participants.

Common Use Cases

• Academic longitudinal research - A university research team deploys anonymized multilingual surveys across 15 countries, using LimeSurvey’s expression engine for adaptive question routing and exporting data directly to R for statistical analysis.
• Enterprise employee engagement programs - An HR department runs quarterly engagement surveys with token-based access, conditional logic to surface department-specific questions, and LDAP integration so employees log in with their corporate credentials.
• Government public consultation - A municipal authority collects citizen feedback on urban planning with GDPR-compliant data storage, WCAG accessibility compliance, and anonymous response collection to encourage honest participation.
• Product market research with conjoint analysis - A product team uses LimeSurvey’s advanced question types and branching logic to run pricing sensitivity studies and feature preference tests, exporting results to SPSS for analysis.
• Clinical and healthcare data collection - A hospital network deploys patient satisfaction surveys on-premises to maintain data sovereignty, using two-factor authentication for staff access and anonymization for patient records.
• Developer-integrated survey workflows - A SaaS platform uses the RemoteControl JSON-RPC API to programmatically generate survey instances, inject pre-filled participant data, and retrieve structured results without any manual admin intervention.

Under The Hood

Architecture LimeSurvey is a PHP monolith built on the Yii 1.1 framework that has evolved through two decades of active development, resulting in a layered architecture where newer patterns coexist with legacy code. A dedicated LSBaseController serves as a transitional base for ongoing refactoring, and a service layer under models/services/ encapsulates domain logic for surveys, question aggregation, and export workflows. However, data access patterns remain inconsistent across the codebase — newer components use proper service classes and constructor injection while older helpers rely on Yii’s static facade pattern and global configuration state. The PluginManager introduces an event-driven extension mechanism that allows deep customization of authentication, question types, export formats, and admin panels without requiring core modifications, providing meaningful modularity despite the overall monolithic structure.

Tech Stack The backend runs PHP 8.1+ on Yii 1.1 with PSR-4 autoloading via Composer, extended by Twig 3.x for server-side templating, PHPMailer for transactional email, TCPDF for PDF generation, and phpseclib for cryptographic operations. Multi-database support spans MySQL, PostgreSQL, MariaDB, and MSSQL through Yii’s active record layer. The frontend combines jQuery and Bootstrap 5 through a Gulp/Browserify/Babel build pipeline, with Chart.js for statistics visualizations, Leaflet for geographic data display, Datatables for response grids, and Tempus Dominus for date inputs. A nascent Vue component signals gradual frontend modernization. The project ships a comprehensive OpenAPI specification alongside its XML-RPC and JSON-RPC RemoteControl API, and deployment configurations support traditional LAMP stacks and Cloud Foundry PaaS environments.

Code Quality PHPUnit drives an extensive multi-tier test suite covering unit, functional, and acceptance scenarios with dedicated suites for the RemoteControl API, expression manager, and service layer. Static analysis tooling includes Psalm with both standard and strict mode configurations plus PHPStan, and phpcs.ruleset.xml enforces coding standards across the codebase. Test quality is uneven — newer service classes in models/services/ have well-structured tests with proper dependency isolation, while older controller and helper code carries limited coverage. Error handling similarly ranges from typed domain exceptions in newer components to more permissive patterns in legacy helpers. The codebase reflects genuine investment in quality infrastructure alongside accumulated technical debt from its age and scale.

What Makes It Unique LimeSurvey’s most technically distinctive innovation is the LimeExpressionManager, a singleton wrapping a recursive descent expression parser that evaluates complex conditional logic, tailoring substitutions, and quota calculations across survey questions, email templates, and validation rules using a unified expression syntax. This capability — real-time expression evaluation spanning the entire survey lifecycle — goes well beyond the simple show/hide rules found in most competing tools. An expression result caching subsystem avoids re-evaluation overhead during multi-page survey navigation. Combined with a plugin architecture that hooks deeply into controller actions and UI rendering, and over 20 years of backward compatibility maintenance, LimeSurvey offers a level of survey workflow flexibility and stability that proprietary SaaS alternatives rarely match.

Self-Hosting

LimeSurvey is licensed under the GNU General Public License version 2.0 (or any later version), which means you can freely use, modify, and redistribute it for any purpose, including commercial applications. The GPL copyleft requirement means that if you distribute a modified version of LimeSurvey itself, those modifications must also be released under the GPL — but this does not affect surveys you run on it, data you collect, or integrations you build against the RemoteControl API. For most self-hosting organizations, the GPL places no practical restrictions on how you use the platform.

Running LimeSurvey yourself requires a PHP 8.1+ web server (Apache or nginx), a supported database (MySQL 8.0+, PostgreSQL 14+, MariaDB 10.3+, or MSSQL 2019+), and sufficient storage for response data, uploaded files, and template assets. The installation process involves Composer for PHP dependencies, a web-based installer, and an optional Yarn/Gulp build step for frontend assets. Ongoing maintenance means applying security patches from the LimeSurvey project, managing database backups, monitoring disk usage as response volumes grow, and handling PHP and database version upgrades over time. This is a well-established deployment pattern for PHP applications, but it does require dedicated operational attention — particularly for organizations that need high availability or handle large concurrent survey loads.

The LimeSurvey organization offers a hosted SaaS tier at limesurvey.org that removes the infrastructure burden entirely, providing managed upgrades, automated backups, and bundled support. The commercial offering also includes access to the LimeSurvey Marketplace for premium themes and question types, along with professional support plans with SLAs that the community forums and GitHub Issues cannot match. Self-hosters gain data sovereignty and the ability to deploy behind corporate firewalls or in air-gapped environments, but they trade away the convenience of managed operations, the assurance of monitored uptime, and access to the broader commercial plugin ecosystem.