Open-source Firebase alternative built on Postgres with auth, storage, realtime, and edge functions.
Open sourceSelf-hostFree / self-hostApache-2.070k★
- Full SQL and the entire Postgres extension ecosystem — no NoSQL trade-offs
- Apache-2.0 licensed and self-hostable with a single Docker Compose command
- Free tier pauses inactive projects after one week, breaking always-on demos
Open-source, local-first Notion alternative built in Rust and Flutter with full self-hosting support.
Open sourceSelf-hostFree / self-hostAGPL-3.062.4k★
- AGPL-licensed core with true local-first storage and full offline support
- Native desktop apps on macOS, Windows, and Linux built with Flutter
- Database feature set is less mature than Notion's — rollups and complex formulas are still catching up
Open-source local-first workspace merging a rich document editor, an infinite whiteboard, and a structured database.
Open sourceSelf-hostFree / self-hostMIT / Custom50.8k★
- Unique whiteboard-meets-document approach covers brainstorming and structured writing in one tool
- Local-first CRDT engine means your data exists on disk before any sync
- Younger project than Notion or AppFlowy — some database features remain early-access
Turn any MySQL, Postgres, SQLite or SQL Server database into a smart spreadsheet UI.
Open sourceSelf-hostFree / self-hostAGPL-3.0 / Open-core49.8k★
- Works with databases you already own — no data migration required
- Both REST and GraphQL APIs generated automatically for every table
- AGPL-3.0 license complicates embedding in proprietary SaaS without a commercial license
Fair-code workflow automation built for technical teams — self-host or use the cloud.
Open sourceSelf-hostFree / self-hostSustainable Use License48k★
- Unlimited workflow runs when self-hosted — no per-task billing
- Code nodes let developers drop into JS or Python for anything the UI can't express
- Fair-code license (Sustainable Use) restricts commercial redistribution of the source
Lightning-fast, typo-tolerant open-source search engine with exceptional developer experience.
Open sourceSelf-hostFree / self-hostMIT47.2k★
- MIT-licensed core — free to self-host with no record or query caps
- One-binary deployment with a straightforward REST API
- Entire index held in memory — RAM requirements grow with dataset size
Open-source BaaS with auth, databases, storage, functions, and messaging in a self-hosted package.
Open sourceSelf-hostFree / self-hostBSD-3-Clause44k★
- Broad SDK coverage across mobile, web, and cross-platform frameworks under one consistent API
- Built-in messaging for push, email, and SMS removes a common third-party integration
- Managed cloud platform is newer and smaller than Supabase's with fewer global regions
Open-source team chat and omnichannel customer messaging platform.
Open sourceSelf-hostFree / self-hostMIT42k★
- MIT license with a large feature set available for free on self-hosted installs
- Omnichannel capabilities blend internal chat and external customer communications
- JavaScript/Meteor stack can be resource-intensive compared to lighter alternatives
Single-file open-source backend — SQLite, auth, realtime, and admin UI packed into one Go binary.
Open sourceSelf-hostFree / self-hostMIT40k★
- Zero external dependencies — one binary is the entire production backend
- Tiny resource footprint runs comfortably on a $5/month VPS or a Raspberry Pi
- SQLite write concurrency ceiling makes it unsuitable for high-write production workloads
Open-source self-hostable platform to deploy apps, databases, and services on your own servers.
Open sourceSelf-hostFree / self-hostApache-2.038.2k★
- Free and self-hostable — one VPS replaces unlimited Heroku dynos
- Web UI covers the full deploy lifecycle without touching the CLI
- Laravel/PHP stack can be heavyweight compared to minimal PaaS alternatives
Open-source low-code framework for building internal apps, admin panels, and dashboards.
Open sourceSelf-hostFree / self-hostApache-2.035.5k★
- Apache-2.0 license with no restrictions on the core
- Self-hostable on any infra, including air-gapped environments
- UI feels less polished than Retool out of the box
Open-source low-code framework to build and deploy internal tools with minimal engineering effort.
Open sourceSelf-hostFree / self-hostAGPL-3.0 / Open-core34k★
- AGPL core is freely self-hostable without per-seat restrictions
- Built-in ToolJet DB gives teams a managed Postgres table editor out of the box
- AGPL license requires open-sourcing modifications if distributed, which complicates enterprise use
Open-source scheduling infrastructure for individuals and teams — self-host or use the cloud.
Open sourceSelf-hostFree / self-hostAGPL-3.033.2k★
- Self-hostable with full data ownership under AGPL
- Generous free cloud tier for individuals
- Self-hosting requires a PostgreSQL database and more infrastructure than a hosted SaaS
Fast, collaborative team wiki with Markdown editing, nested collections, and a self-hostable server.
Open sourceSelf-hostFree / self-hostBSL 1.132.1k★
- Clean, fast reading and writing experience purpose-built for team wikis
- Self-hostable with Docker — source available under BSL with a one-year delay to open source
- BSL license means commercial redistribution is restricted; it is not classic OSI open source
Open-source, self-hosted team messaging built for security-conscious and DevOps teams.
Open sourceSelf-hostFree / self-hostMIT / Open-core32k★
- Full data sovereignty — runs on your own servers with no vendor access
- MIT-licensed core is free to self-host with no seat caps
- UI and mobile experience lag behind Slack's polish
Minimalist self-hosted PaaS powered by Docker — git push to deploy on a single Linux server.
Open sourceSelf-hostFree / self-hostMIT30.1k★
- Extremely lightweight — minimal resource overhead on a single server
- MIT-licensed with a decade of production battle-testing
- No web UI — every operation is CLI or SSH, which raises the floor for non-developers
Simple, self-hostable analytics with MIT licensing, no pageview caps, and a free cloud tier.
Open sourceSelf-hostFree / self-hostMIT26k★
- MIT license — fully free to self-host with no feature gates or pageview limits
- Deploys in minutes to Vercel or any Node host without operational complexity
- No native funnels, session replay, or A/B testing capabilities
Modern open-source CRM with a Notion-style UI and developer-first architecture.
Open sourceSelf-hostFree / self-hostAGPL-3.025.4k★
- Clean, modern UI that feels fast and uncluttered
- Fully customizable data model without needing a consultant
- Relatively young project — some enterprise features still maturing
Open-source low-code platform with a built-in database for building internal apps fast.
Open sourceSelf-hostFree / self-hostGPL-3.0 / Open-core24.5k★
- Built-in database removes the need to provision a separate data store for simple apps
- GPL core is freely self-hostable with no seat limits
- BudibaseDB is not suitable for high-volume transactional workloads
Open-source product analytics suite with events, funnels, session replay, feature flags, and A/B tests.
Open sourceSelf-hostFree / self-hostMIT24k★
- Single platform replaces GA, Hotjar, LaunchDarkly, and parts of Segment
- Generous free cloud tier — 1 million events per month at no cost
- Self-hosting at scale requires Kafka, ClickHouse, and Redis — significant ops burden
Battle-tested open-source identity and access management with SSO, OIDC, and SAML.
Open sourceSelf-hostFree / self-hostApache-2.023.5k★
- Apache-2.0 licensed — completely free with no seat or MAU limits
- CNCF-incubating project with Red Hat backing and a decade of production hardening
- Java-based stack is resource-heavy and slow to cold-start compared to modern alternatives
Open-source, in-memory typo-tolerant search engine optimized for millisecond performance.
Open sourceSelf-hostFree / self-hostGPL-3.021.3k★
- Exceptionally low and predictable query latency due to pure in-memory architecture
- Algolia-compatible InstantSearch adapter makes migration straightforward
- GPL-3.0 license requires careful review for proprietary commercial products
Lightweight, cookieless web analytics that is GDPR-friendly out of the box.
Open sourceSelf-hostfrom $9/moAGPL-3.021k★
- No cookies means legally simpler GDPR/CCPA compliance without a consent flow
- Sub-1 KB tracking script with no measurable page-weight impact
- No session replay, heatmaps, or multi-step funnel visualization
Self-hosted, high-performance newsletter and mailing-list manager — pair with any SMTP provider.
Open sourceSelf-hostFree / self-hostAGPL-3.016.1k★
- Zero per-contact or per-send cost — pay only for SMTP delivery
- Single Go binary with PostgreSQL — trivial to run on a cheap VPS
- No hosted/managed version — you own infrastructure, backups, and deliverability
Modern open-source identity provider with a clean UI, supporting SSO, OIDC, SAML, and LDAP.
Open sourceSelf-hostFree / self-hostMIT / Open-core14.2k★
- Significantly friendlier admin UX than Keycloak — less XML, no realm mental model
- MIT-licensed community edition is free with no MAU or seat limits
- Enterprise features (audit logs, support SLAs) require a paid license
Open-source no-code database built natively on Postgres — real-time, API-first, and Airtable-compatible.
Open sourceSelf-hostFree / self-hostAGPL-3.014.2k★
- Pure Postgres-native storage means you can query Teable data directly via SQL
- Real-time collaboration built in from the ground up, not added on
- Younger project with a smaller community and integration ecosystem than NocoDB or Baserow
Open-source self-hosted PaaS with a web dashboard, Docker Swarm orchestration, and one-click app templates.
Open sourceSelf-hostFree / self-hostApache-2.014.1k★
- Web UI makes self-hosted PaaS accessible to teams unfamiliar with terminal deployments
- One-click app catalog covers most common open-source stacks instantly
- Docker Swarm is less popular than Kubernetes for large-scale production workloads
Open-source authentication with session management, social login, and passwordless — self-host or managed.
Open sourceSelf-hostFree / self-hostApache-2.013.8k★
- Apache-2.0 licensed core is free to self-host with no MAU or seat limits
- Recipe-based architecture lets you mix and match auth methods modularly
- Enterprise features like SAML SSO and SCIM provisioning require the paid managed plan
MIT-licensed no-code automation platform with an AI-first design and clean Zapier-like interface.
Open sourceSelf-hostFree / self-hostMIT11k★
- Pure MIT license — no commercial-use restrictions unlike n8n's fair-code terms
- No-code-first UX makes it accessible to non-developers
- Smaller connector library than Zapier or n8n today
Open-source DocuSign alternative for self-hosted digital document signing with no per-envelope fees.
Open sourceSelf-hostFree / self-hostAGPL-3.011k★
- AGPL-licensed with full self-hosting — signing data never leaves your own infrastructure
- Per-seat cloud pricing with no per-document or per-envelope fees at any volume
- AGPL-3.0 license requires sharing modifications if you distribute the software commercially
Open-source developer platform that turns scripts into production workflows, scheduled jobs, and internal UIs.
Open sourceSelf-hostFree / self-hostAGPL-3.011k★
- Scripts are first-class citizens — no shoehorning real code into config-file automation
- App builder turns backend scripts into shareable internal tools with zero frontend work
- AGPL license requires derivative works to be open-sourced unless using a commercial license
Open-source experience-management platform for targeted in-app and link surveys.
Open sourceSelf-hostFree / self-hostAGPL-3.09.2k★
- AGPL core is free with unlimited responses on self-hosted deployments
- Event-based targeting lets you survey specific user cohorts at precise moments
- AGPL license requires open-sourcing modifications if distributed commercially
Open-source customer data platform built around the warehouse, with self-hosting and 200+ destinations.
Open sourceSelf-hostFree / self-hostAGPL-3.0 / Open-core4.2k★
- AGPL core is self-hostable with no event-volume billing on your own infra
- Segment-compatible API makes migration a drop-in replace for instrumentation
- AGPL license requires open-sourcing modifications to the server if distributed externally
Open-source event ingestion and data pipeline that streams clicks, events, and identities straight to your warehouse.
Open sourceSelf-hostFree / self-hostMIT4.1k★
- MIT license — freely self-hostable with full source access and no usage-based billing
- ClickHouse-native support delivers sub-second query performance on billions of events
- Primarily an ingestion layer — lacks Segment's breadth of 400+ maintained destination connectors
Mature, self-hostable open-source CRM with deeply customizable entities and business-process automation.
Open sourceSelf-hostFree / self-hostAGPL-3.02.1k★
- Battle-tested codebase with over a decade of production use
- Highly customizable without needing to modify core code
- PHP/legacy stack is less attractive to modern JavaScript developers
Spreadsheet-database hybrid for building collaborative apps and trackers.
Proprietaryfrom $20/moProprietary
- Polished, beginner-friendly interface
- Huge ecosystem of templates and integrations
- Per-seat pricing scales painfully for larger teams
Hosted search-as-a-service API delivering fast, relevant search with minimal setup.
ProprietaryFree / self-hostProprietary
- Extremely fast global performance with zero infrastructure to manage
- Well-documented SDKs and UI component libraries speed up integration
- Costs scale quickly — pricing is based on both records and search operations
Identity-as-a-service platform for adding authentication and authorization to any application.
Proprietaryfrom $35/moProprietary
- Fastest path to production-grade auth — SDKs for every major language and framework
- Handles compliance edge-cases (MFA, adaptive auth, brute-force protection) out of the box
- MAU-based pricing escalates sharply past the free tier, especially after Okta acquisition
Open-source no-code database you can self-host, with a familiar Airtable-style UI.
Open sourceSelf-hostFree / self-hostMIT / Open-core
- MIT-licensed core you can run for free
- One-command Docker self-hosting
- Some advanced features are paid/enterprise
Automated scheduling tool that eliminates meeting coordination back-and-forth.
Proprietaryfrom $10/moProprietary
- Polished, frictionless booking experience for invitees
- Wide integration ecosystem covering most business tools
- Per-seat pricing makes team deployments expensive fast
Market-leading e-signature platform trusted by enterprises for legally binding document workflows.
Proprietaryfrom $10/moProprietary
- Widely recognized brand gives recipients immediate trust before they open the document
- Deep native integrations with Salesforce, SAP, and Microsoft 365 require no custom code
- Per-envelope allowances on lower plans fill up quickly; overage charges are not prominently flagged
Google's all-in-one BaaS platform with Firestore, Auth, hosting, and serverless functions.
ProprietaryFree / self-hostProprietary
- Generous Spark free tier covers most prototype and small-app needs with no credit card
- Native iOS and Android SDKs handle offline caching and sync automatically
- Vendor lock-in to Google infrastructure with no self-hosting or data export path
Google's dominant web analytics platform, now built on the event-based GA4 model.
ProprietaryFree / self-hostProprietary
- Free for most websites with extremely generous traffic limits
- Tight integration with Google Ads, Looker Studio, and Search Console
- Requires cookie consent banners under GDPR, adding compliance overhead
Managed cloud application platform that lets you deploy, run, and scale apps without managing servers.
Proprietaryfrom $5/moProprietary
- Zero infrastructure configuration — git push and it runs
- Massive add-on marketplace covers most backend needs
- Free tier was removed in November 2022, raising the floor cost
All-in-one email marketing platform for campaigns, automations, and audience growth.
Proprietaryfrom $13/moProprietary
- Beginner-friendly interface with a very shallow learning curve
- Strong template library and design tools for non-designers
- Contact-based pricing escalates steeply — billed on total list size including unsubscribes
All-in-one connected workspace combining docs, wikis, and databases in a single flexible canvas.
Proprietaryfrom $10/moProprietary
- Highly flexible page model adapts to docs, project trackers, CRMs, and wikis equally well
- Polished cross-platform apps with reliable real-time collaboration
- No self-hosting option — all data lives on Notion's servers with no local-first mode
Low-code platform for building internal tools and admin panels using drag-and-drop components.
Proprietaryfrom $10/moProprietary
- Fastest path from a database query to a working admin UI
- Deep connector library reduces integration boilerplate
- Per-user billing escalates sharply as team grows
Enterprise CRM and cloud platform for sales, service, and marketing automation.
Proprietaryfrom $25/moProprietary
- Deeply configurable to match almost any sales process
- Vast ecosystem of integrations, partners, and certified consultants
- Per-seat subscription pricing becomes very expensive for growing teams
Customer data platform that collects events from every touchpoint and routes them to your tools.
ProprietaryFree / self-hostProprietary
- Widest destination catalog in the category — 400+ integrations maintained by Segment
- Segment.io analytics.js is the de-facto industry standard event schema
- Event-volume billing grows steeply with traffic — warehouse-first alternatives often cheaper at scale
Cloud-hosted team messaging and channels platform, owned by Salesforce.
Proprietaryfrom $7.25/moProprietary
- Best-in-class UX and near-universal adoption makes onboarding new hires trivial
- Enormous app ecosystem covers almost every SaaS integration
- Per-user billing escalates steeply as headcount grows
Notion-like form builder with unlimited free forms and responses on the free plan.
Proprietaryfrom $29/moProprietary
- Genuinely unlimited forms and responses at no cost — rare in the category
- Block editor makes complex form layouts fast to build without a learning curve
- Tally branding appears on free-plan forms and cannot be removed without upgrading
Conversational online forms and surveys with a distinctive one-question-at-a-time flow.
Proprietaryfrom $25/moProprietary
- Conversational UI consistently outperforms traditional form layouts for completion rates
- Polished visual design requires no customization to look professional
- Response limits on lower-tier plans push active users to expensive subscriptions quickly
Hosted automation platform connecting 6,000+ apps via point-and-click Zaps.
Proprietaryfrom $20/moProprietary
- Largest integration library in the category by far
- No technical knowledge needed to build most workflows
- Per-task metering makes high-volume automation expensive fast