Proof Holdings vs HumanLayer
HumanLayer pioneered human-in-the-loop approvals for AI agents — then pivoted, in late 2025, to an AI coding IDE. Its founder now calls the original approval SDK "pretty much all deprecated." If you came looking for HumanLayer's approval API, here's what happened and the purpose-built alternative.
The pioneer pivoted; the need didn't. Proof is a maintained, purpose-built approval API — request out, human decision over Telegram/WhatsApp back, signed ES256 token in hand — with 300 free approvals a month to migrate onto.
One API · One key
One key does what a stack of vendors does
Every platform on this page treats human approval as one feature among many. Proof is a single API where the approval is the product — the same flow returns a signed, offline-verifiable ES256 token for each of these:
Flat price · Any asset
One flat price for every asset — phone, email, and domain today, with wallet and social coming soon. No per-seat, no per-MAU, no per-verification tiers — the meter that makes every rival's bill jump.
- Free every month
- 300 proofs
- Pay as you go
- €0.03 / proof
- At volume
- €0.0079 / proof
Feature Comparison
Swipe to compare →
| Feature | Proof Holdings | HumanLayer |
|---|---|---|
| Human-in-the-loop approval product | Live, purpose-built | Deprecated (pivoted to an AI coding IDE) |
| What it is today | Approval API → portable proof token | AI coding IDE ('Token Smarter, not Harder') |
| Approval SDK status | Actively developed | "Pretty much all deprecated" (founder) |
| Signed, portable proof (old product) | ES256 JWT, offline-verifiable | No |
| Delivery channel | Telegram, WhatsApp | Was Slack / Email / Discord |
| Pricing | Per-proof (€0.0079) | Per-seat coding IDE (Pro $100/user/mo) |
| Actively maintained for approvals | Yes | No |
Pricing
Is the approval product available?
Proof Holdings
Yes — live and maintained
HumanLayer
No — SDK deprecated, company pivoted
What you'd buy today
Proof Holdings
An approval API with a signed proof token
HumanLayer
An AI coding IDE, priced per seat ($100/user/mo)
Proof of the decision
Proof Holdings
Portable ES256 token, verifiable offline
HumanLayer
The old product produced no portable signed proof
AI coding environment
Proof Holdings
Not what Proof does
HumanLayer
That's HumanLayer's product now
What HumanLayer was — and why it's here
Credit where due: HumanLayer (YC F24) defined this category. Its SDK wrapped risky agent tool calls with an `@require_approval()` decorator and a `human_as_tool` helper, routing approvals over Slack, email, and Discord with escalations, timeouts, and multi-approver flows. For a while it was the closest thing to a purpose-built human-in-the-loop approval API for AI agents.
It's in this comparison because people still search for it — but the important update: HumanLayer pivoted. Through late 2025 it became an AI coding IDE ("Token Smarter, not Harder"), and its founder's own GitHub README now reads that the original code is "pretty much all deprecated." The latest release is literally tagged `codelayer-0.20.0`. The approval product you may be looking for is no longer the company's focus.
The category didn't go away — the product did
HumanLayer's pivot doesn't mean AI agents stopped needing human approval — if anything the opposite. It means the purpose-built approval layer is now an open space. Proof Holdings fills it: request an approval, a human decides over Telegram or WhatsApp with no app install, and you get back an ES256 proof token any third party can verify offline.
That last part is something even peak HumanLayer didn't offer: a portable, cryptographic proof of the decision. Approvals over Slack/email returned a function result recorded in HumanLayer's system, not a signature you could hold. So if you arrived here comparing the two, the real answer is that they're no longer the same kind of thing — one is an AI coding tool, the other is the live, verifiable approval API.
When to use HumanLayer
- You actually want an AI coding IDE / agentic coding environment (HumanLayer's product today)
- You're following the founder's "12-factor agents" work and want that toolchain
- You're evaluating per-seat coding tools, not an approval API
When to use Proof Holdings
- You came for human-in-the-loop approvals — the product HumanLayer deprecated
- You want a live, maintained approval API, not a pivoted one
- You want a portable ES256 proof token for every approval decision
- You want approvals over Telegram/WhatsApp with no app install
- You want per-approval pricing, not a per-seat coding-tool subscription
- You need non-repudiation the old HumanLayer approval flow never produced
Frequently Asked Questions
Ready to try Proof Holdings?
300 free proofs per month. No credit card required.
Building with an AI agent? The 176-tool MCP server and test mode let an agent run a real verification right now — machine quickstart in llms-full.txt.