
Langfuse
LangSmith
Hugging Face
Haystack NLP Framework
Helicone AI
liteLLM
OpenAI
Framework for building applications with LLMs through composability

AgentGatePay
x402
Real-world tasks your agent can't do alone.

Which is more popular?
Based on our record, LangChain should be more popular than Underscore Done. It has been mentioned 4 times since March 2021.
Website, pricing, platforms and company facts side by side.
|
|
|
|
|---|---|---|
| Website | langchain.com | underscoredone.com |
| Pricing | — | |
| Company | — | Startup from the United States · 2026 |
| Listed in |
In their own words, as submitted to SaaSHub.


No description of LangChain yet.
Underscore Done (_done) is a suite of pay-per-call utility APIs built for AI agents. No API keys, no subscriptions - agents pay per request with USDC via the x402 protocol
What each product offers, as listed by its team.


Possible disadvantages
No features have been listed yet.
An editorial look at what each product does well and who it suits.


Overall verdict
Why this product is good
Recommended for
No analysis of Underscore Done yet.
Walkthroughs and reviews on video.
LangChain for LLMs is... basically just an Ansible playbook
More videos
No Underscore Done videos yet. You could help us improve this page by suggesting one.
How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing LangChain and Underscore Done.
Underscore Done's answer:
We provide data and actions that AI cannot achieve.
Also we don't require accounts, registration, api keys. And we charge per usage and never charge monthly subscriptions.
Underscore Done's answer:
Ai Agents that work on behalf of people.
Share your experience with using LangChain and Underscore Done. For example, how are they different and which one is better?
Recommendations tracked on public social media and blogs since March 2021.


Undoubtedly, LangChain is the most popular framework for AI application development at the moment. The advent of LangChain has greatly simplified the construction of AI applications based on Large Language Models (LLM). If we compare an... - Source: dev.to / over 2 years ago
Developed using Langchain and Streamlit technologies for enhanced performance. - Source: dev.to / over 2 years ago
LangChain was first released in October 2022 as an open-source side project, a framework that makes developing AI applications more flexible. It got so popular that it was promptly turned into a startup. - Source: dev.to / over 2 years ago
_done is a catalog of small, pay-per-call utility APIs aimed at AI agents: things like DNS and WHOIS lookups, screenshots, OCR, hashing, QR codes, and SEO extraction. Every call costs one cent in USDC over x402. There's no account and no... - Source: dev.to / 13 days ago
When comparing LangChain and Underscore Done, you can also consider the following products.

Langfuse is an open-source LLM engineering platform that helps teams collaboratively debug, analyze, and iterate on their LLM applications.
Compare Langfuse to LangChain or Underscore Done:

Enable AI agents to make autonomous payments with AP2 mandates and X402 protocol. Multi-chain crypto, budget controls, instant settlement.
Compare AgentGatePay to LangChain or Underscore Done:

Build and deploy LLM applications with confidence
Compare LangSmith to LangChain or Underscore Done:

An open protocol for internet-native payments from Coinbase
Compare x402 to LangChain or Underscore Done:

The AI community building the future. The platform where the machine learning community collaborates on models, datasets, and applications.
Compare Hugging Face to LangChain or Underscore Done:

Haystack is an open source NLP framework to build applications with Transformer models and LLMs.
Compare Haystack NLP Framework to LangChain or Underscore Done: