Blockchain-powered verification
Tamper-proof digital records for organizations that move fast
Stamp any file to the blockchain and make it instantly verifiable — credentials, legal documents, AI artifacts, and more. Set up a turnkey platform in minutes or integrate via API into any system.
const res = await fetch(“https://service-link.clstamp.com/webhook/YOUR_API_KEY”, {
method: “POST”,
headers: {
“secret-key”: “YOUR_SECRET_KEY”,
“group-id”: “my-credentials”,
“stamp-immediately”: “true”
},
body: formData // FormData with ‘file’ field
});// Response
{ “success”: true,
“hash”: “Qm…”,
“files_stamped”: 1,
“network”: “public” }
Try it yourself
See blockchain credentials in action— Right Now
This quiz was vibecoded using the Chainletter API. Take it, pass it, and receive a real blockchain-stamped credential — verifiable by anyone, forever. It’s a working example of how fast organizations can build with Chainletter.
Take a short quiz about blockchain credentials. Pass and you’ll receive a tamper-proof, blockchain-stamped certificate — issued automatically through the Chainletter API. It’s real, it’s verifiable, and it took us minutes to build from scratch. That’s the power of the API.
The problem
Digital records weren’t built for the speed of today
Organizations are under pressure to modernize, but the records they produce — credentials, contracts, AI-generated work — are easy to fake and slow to verify.
AI tools can generate convincing diplomas, legal documents, and certificates in minutes — traditional PDFs offer no built-in protection
Employers, courts, and counterparties wait days or weeks for organizations to manually confirm records via email or phone
Legacy systems require long procurement cycles, IT projects, and months of implementation before a single record is stamped
Markets we serve
Trusted records for every sector
Anywhere trust matters and records need to be verified, Chainletter delivers tamper-proof proof.
Education
Academic credentials
Stamp diplomas, transcripts, certificates, and badges that graduates can share instantly with employers, licensing boards, and other universities. Give academic records the permanence they deserve.
Legal
Legal documents
Create verifiable wills, trusts, power of attorney documents, and contracts. Blockchain stamping gives legal records an immutable chain of custody that holds up when it matters most.
AI & LLM
AI skills & artifacts
Stamp provenance onto AI-generated skills, prompts, and artifacts. As agents create and share work, blockchain records prove authorship, version history, and trust in a decentralized ecosystem.
Why blockchain
Records that can’t be faked. Even by AI
Stamping records on the blockchain solves every weakness of traditional digital files.
Tamper-proof
Immutable by design
Once a record is stamped on the blockchain, it cannot be altered, backdated, or deleted — by anyone, including Chainletter. The cryptographic hash makes forgery mathematically impossible.
Instant
Verify in seconds
Anyone with the file can verify its authenticity instantly — no phone calls, no emails, no waiting. Employers, courts, licensing boards, and AI agents get a definitive answer immediately.
Permanent
Outlasts any organization
Blockchain records exist independently of Chainletter or the issuing organization. Even if an entity closes, its stamped records remain verifiable forever on the public blockchain.
Two ways to get started
Get the platform or API live in minutes
Whether you want a turnkey solution or full integration control, Chainletter’s flexible architecture meets you where you are.
Turnkey
Stamping platform
A fully hosted, private-label portal where your team uploads files and issues blockchain-stamped records. No coding required. Set up in minutes, stamp records in seconds.
Includes:
Custom-branded portal at your subdomain
Drag-and-drop file upload
Automatic blockchain stamping
Recipient email distribution
Public verification page
Works with Canva, LinkedIn, and more
Developer
Stamping API
Integrate blockchain stamping directly into your LMS, document management system, or any application. RESTful endpoints, webhook events, and real-time SSE for instant verification.
Includes:
File upload and management API
Blockchain stamping via webhook
Real-time SSE event streaming
Full OpenAPI / Swagger documentation
AI and LLM agent-friendly architecture
Implement in hours with a few lines of code
AI-ready architecture
Built for AI-driven organizations
Chainletter’s API is designed to work seamlessly with AI LLMs and autonomous agents, so your organization can automate stamping workflows at scale.
LLM-friendly
Clean, documented API
RESTful endpoints with full OpenAPI specs make it easy for AI coding assistants and LLMs to generate working integrations, reducing development time from weeks to hours.
Agentic
Agent-ready workflows
AI agents can call the Chainletter API to stamp records as part of automated workflows — from course completions to legal signing events to artifact provenance tracking.
Real-time
Event-driven by design
Server-sent events stream stamp confirmations in real time, so agents and systems can react instantly. No polling, no delays, no manual intervention.
Why Chainletter
Join the new technology era — without the wait
No blockchain expertise needed. No crypto wallets. No months-long IT projects.
Your branded stamping portal is live the same day. No procurement cycle, no IT project, no waiting
No wallets, no tokens, no blockchain knowledge needed; just upload, stamp, and distribute
Compatible with any LMS, SIS, document management system, or AI agent framework
Cryptographic hashes create proof that AI tools cannot forge, replicate, or reverse-engineer
Records are verified against the public blockchain, not our servers. Your records survive no matter what
Use Canva for design, LinkedIn for distribution, and AI agents for automation
Backed by Qubic Labs — Proud recipient of a 2025 development grant from blockchain accelerator Qubic Labs.
Get started
Start stamping trusted records today
Your organization can be issuing verifiable digital records in minutes. No blockchain experience required.
