head to head · open source
OpenAPI-Specification vs Tailcall
OpenAPI-Specification has 31,295 GitHub stars, 9,144 forks, 80 open issues and last shipped 2 days ago. Tailcall has 7,633 stars, 1,456 forks, 45 open issues and last shipped 2 days ago. OpenAPI-Specification leads on adoption by 310% (31,295 vs 7,633 stars). OpenAPI-Specification is written in Markdown under Apache-2.0; Tailcall is written in Rust under Apache-2.0. OpenAPI-Specification has attracted 29% as many forks as stars, Tailcall 19%. OpenAPI-Specification was the more recently maintained of the two, and both are self-hostable with no licence fee.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| OpenAPI-Specification | Tailcall | |
|---|---|---|
| GitHub stars | ★ 31K | ★ 7.6K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Markdown | Rust |
| Last push | 2026-11-03 | 2026-11-03 |
| Forks | ⑂ 9.1K | ⑂ 1.5K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick OpenAPI-Specification if
- You weight community size — 31K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Markdown
- You value the larger contributor base for long-term maintenance
pick Tailcall if
- You want the Tailcall feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Rust
- You evaluated both and Tailcall fits your workflow better
About OpenAPI-Specification
The OpenAPI Specification The OpenAPI Specification is a community driven open specification within the OpenAPI Initiative, a Linux Foundation Collaborative Project. The OpenAPI Specification (OAS) defines a standard, programming language agnostic interface description for HTTP APIs. This allows both humans and computers to discover and understand the capabilities of a service without requiring access to source code, additional documentation, or inspection of network traffic. When properly defined via OpenAPI, a consumer can understand and interact with the remote service with a minimal amount of implementation…
read the full OpenAPI-Specification overview →
About Tailcall
⚒️ Forge: AI Enhanced Terminal Development Environment A comprehensive coding agent that integrates AI capabilities with your development environment curl fsSL sh Table of Contents Quickstart Usage Examples Why Forge? How Forge Works: Three Modes Interactive Mode (TUI) One Shot CLI Mode ZSH Plugin Mode ( : prefix) ZSH Plugin: The : Prefix System Agents Sending Prompts Attaching Files Conversation Management Git Integration Shell Command Tools Session & Configuration Skills Customizing Agent Behavior Semantic Search (Workspace) Quick Reference: All : Commands Command Line Options Advanced Configuration Provider…
read the full Tailcall overview →
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Frequently asked questions
Is OpenAPI-Specification or Tailcall more popular?
OpenAPI-Specification has 31,295 GitHub stars and Tailcall has 7,633. OpenAPI-Specification has the larger community by that measure.
Are OpenAPI-Specification and Tailcall free?
Both are open source. OpenAPI-Specification is licensed under Apache-2.0 and Tailcall under Apache-2.0. Neither carries a licence fee.
What is the difference between OpenAPI-Specification and Tailcall?
OpenAPI-Specification is written in Markdown and Tailcall in Rust. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, OpenAPI-Specification or Tailcall?
Choose OpenAPI-Specification if you want the larger community (31,295 stars) or its Apache-2.0 licence terms. Choose Tailcall if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.