Public Grid
How Public Grid went from bare Postgres to a production-grade ledger
Got asked to move money? Don't build it from scratch.
Blnk helps developers confidently ship their financial products without compromising accuracy or compliance.
Blnk gives you a production-grade, open-source ledger that fits your workflow and keeps balances correct.
Used in production by real teams:
Start building
Built for developers who move money
Here's the idea. If you build features that send, receive or hold value: money, assets, stocks, tokens, etc. — Blnk's got you covered.
Ready to get started?
Deploy your ledger in 15 minutes, start building immediately, or contact us to discuss your product.
Use Cases
Perfect for any idea you want to build
Here's the idea. If you build features that send, receive or hold value: money, assets, stocks, tokens, etc. — Blnk's got you covered.
Wallets
Everything a wallet needs
Ship seamless wallet experiences your users love, powered by a reliable financial ledger.
Fintech
Better fintech products
Skip half the work and build financial accounts, cards, lending, escrow, and payments on a solid financial Core.
Crypto
Accuracy to the smallest satoshi
One ledger for your app's financial activities across both fiat and crypto workflows. Supports any currency.
Payments
Move money confidently
Handle complex money movement across processors, banks, and internal systems, with reconciliation built in.
AI
Finance meets AI
Enjoy an intuitive ledger that gives your AI systems clean, structured financial data to learn and act on.
SaaS
Your billing, your rules
Power your billing, from prepaid and postpaid plans to wallet tracking, invoicing, and credits.
Wallets
Build your wallet, in any currency
Your app is the point of sale. Users can accept contactless payments from physical cards and digital wallets—no extra hardware required.
Field service jobs, farmers' markets, concerts, and other events are perfect use cases for accepting in-person payments.
Crypto
Keep on-ramp & off-ramp transactions in sync
Your app is the point of sale. Users can accept contactless payments from physical cards and digital wallets—no extra hardware required.
Field service jobs, farmers' markets, concerts, and other events are perfect use cases for accepting in-person payments.
Lending
Manage loans and track repayments
Your app is the point of sale. Users can accept contactless payments from physical cards and digital wallets—no extra hardware required.
Field service jobs, farmers' markets, concerts, and other events are perfect use cases for accepting in-person payments.
Fintech
Confidently ship any fintech feature
Your app is the point of sale. Users can accept contactless payments from physical cards and digital wallets—no extra hardware required.
Field service jobs, farmers' markets, concerts, and other events are perfect use cases for accepting in-person payments.
AI
Build AI-powered accounting features
Your app is the point of sale. Users can accept contactless payments from physical cards and digital wallets—no extra hardware required.
Field service jobs, farmers' markets, concerts, and other events are perfect use cases for accepting in-person payments.
Payments
Track money movement across payment methods
Your app is the point of sale. Users can accept contactless payments from physical cards and digital wallets—no extra hardware required.
Field service jobs, farmers' markets, concerts, and other events are perfect use cases for accepting in-person payments.
SaaS
Build your own billing system
Your app is the point of sale. Users can accept contactless payments from physical cards and digital wallets—no extra hardware required.
Field service jobs, farmers' markets, concerts, and other events are perfect use cases for accepting in-person payments.
Programmable ledger API
Build with tools you already use
Blnk is API-first, with SDKs that let you integrate quickly in the languages you already use.
Explore documentation
Language-agnostic
You can use Blnk with any programming language, framework or stack.
Seamless integration
Plug Blnk into your existing apps and systems without rebuilding your core logic.
Great developer experience
Get started in 5 minutes with our comprehensive docs or get answers from our Discord community.
cURL
Node.js
Go
Python
PHP
Java
1
2
3
4
5
6
7
8
9
10
11
curl -X POST http://localhost:5001/transactions \
-H 'Content-Type: application/json' \
-d '{
"amount": 1230.12,
"precision": 100,
"currency": "USD",
"source": "@FundingPool",
"destination": "@Frederick-Bates",
"reference": "ref_funding_001",
"description": "Wallet funding"
}'
-H 'Content-Type: application/json' \
-d '{
"amount": 1230.12,
"precision": 100,
"currency": "USD",
"source": "@FundingPool",
"destination": "@Frederick-Bates",
"reference": "ref_funding_001",
"description": "Wallet funding"
}'
1
2
3
4
5
6
7
8
9
10
11
async function createTransaction() {
const tx = await blnk.transactions.create({
amount: 1230.12,
precision: 100,
currency: "USD",
source: "@FundingPool",
destination: "@Frederick-Bates",
reference: "ref_funding_001",
description: "Wallet funding"
});
}
const tx = await blnk.transactions.create({
amount: 1230.12,
precision: 100,
currency: "USD",
source: "@FundingPool",
destination: "@Frederick-Bates",
reference: "ref_funding_001",
description: "Wallet funding"
});
}
1
2
3
4
5
6
7
8
9
10
11
12
13
func main() {
client := blnk.NewClient("http://localhost:5001")
client.Transactions.Create(context.TODO(), blnk.Transaction{
Amount: 1230.12,
Precision: 100,
Currency: "USD",
Source: "@FundingPool",
Destination: "@Frederick-Bates",
Reference: "ref_funding_001",
Description: "Wallet funding",
})
}
client := blnk.NewClient("http://localhost:5001")
client.Transactions.Create(context.TODO(), blnk.Transaction{
Amount: 1230.12,
Precision: 100,
Currency: "USD",
Source: "@FundingPool",
Destination: "@Frederick-Bates",
Reference: "ref_funding_001",
Description: "Wallet funding",
})
}
1
2
3
4
5
6
7
8
9
10
11
import requests
requests.post("http://localhost:5001/transactions", json={
"amount":1230.12,
"precision":100,
"currency":"USD",
"source":"@FundingPool",
"destination":"@Frederick-Bates",
"reference":"ref_funding_001",
"description":"Wallet funding"
})
requests.post("http://localhost:5001/transactions", json={
"amount":1230.12,
"precision":100,
"currency":"USD",
"source":"@FundingPool",
"destination":"@Frederick-Bates",
"reference":"ref_funding_001",
"description":"Wallet funding"
})
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
$ch = curl_init("http://localhost:5001/transactions");
curl_setopt_array($ch, [
CURLOPT_POST => true,
CURLOPT_HTTPHEADER => ["Content-Type: application/json"],
CURLOPT_POSTFIELDS => json_encode([
"amount" => 1230.12,
"precision" => 100,
"currency" => "USD",
"source" => "@FundingPool",
"destination" => "@Frederick-Bates",
"reference" => "ref_funding_001",
"description" => "Wallet funding"
]),
]);
curl_exec($ch);
curl_setopt_array($ch, [
CURLOPT_POST => true,
CURLOPT_HTTPHEADER => ["Content-Type: application/json"],
CURLOPT_POSTFIELDS => json_encode([
"amount" => 1230.12,
"precision" => 100,
"currency" => "USD",
"source" => "@FundingPool",
"destination" => "@Frederick-Bates",
"reference" => "ref_funding_001",
"description" => "Wallet funding"
]),
]);
curl_exec($ch);
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
HttpRequest request = HttpRequest.newBuilder()
.uri(URI.create("http://localhost:5001/transactions"))
.header("Content-Type","application/json")
.POST(HttpRequest.BodyPublishers.ofString("""
{ "amount":1230.12,
"precision":100,
"currency":"USD",
"source":"@FundingPool",
"destination":"@Frederick-Bates",
"reference":"ref_funding_001",
"description":"Wallet funding"
}
"""))
.build();
HttpClient.newHttpClient()
.send(request, HttpResponse.BodyHandlers.discarding());
.uri(URI.create("http://localhost:5001/transactions"))
.header("Content-Type","application/json")
.POST(HttpRequest.BodyPublishers.ofString("""
{ "amount":1230.12,
"precision":100,
"currency":"USD",
"source":"@FundingPool",
"destination":"@Frederick-Bates",
"reference":"ref_funding_001",
"description":"Wallet funding"
}
"""))
.build();
HttpClient.newHttpClient()
.send(request, HttpResponse.BodyHandlers.discarding());
HTTP 200 OK
{
"id": "txn_6164573b-6cc8-45a4-ad2e-7b4ba6a60f7d",
"status": "APPLIED",
"created_at": "2025-10-12T01:36:46.997063436Z",
"amount": 1230.12,
"precision": 100,
"precise_amount": 123012,
"currency": "USD",
"source": "@FundingPool",
"destination": "@Frederick-Bates",
"reference": "ref_funding_001",
"description": "Wallet funding"
}
"id": "txn_6164573b-6cc8-45a4-ad2e-7b4ba6a60f7d",
"status": "APPLIED",
"created_at": "2025-10-12T01:36:46.997063436Z",
"amount": 1230.12,
"precision": 100,
"precise_amount": 123012,
"currency": "USD",
"source": "@FundingPool",
"destination": "@Frederick-Bates",
"reference": "ref_funding_001",
"description": "Wallet funding"
}
Integration was seamless, and the fact that it's open-source adds flexibility. On top of that, Blnk is incredibly fast, making it a solid choice for high-performance financial systems.
Open-source ledger
Build any transaction workflow, fast.
Ship workflows faster without rebuilding your ledger. Define deposits, payouts, wallets, lending, and many more with just a few API calls.
Download Blnk Core
Skip the heavy lifting
Implement what used to take days in minutes — from simple to complex workflows.
Modular by design
It's like legos. Combine building blocks to craft the workflow that fits your product.
Built on double-entry
Enforces accuracy, traceability, and compliance in every transaction.
We had the licenses and the infrastructure, but without a financial core, we couldn’t move forward. Blnk gave us the foundation to build on.
Insights
Get a 360-degree view into your ledger
Investigate transactions, generate reports, handle back-office ops, and collaborate with your team on financial data.
Open Blnk Cloud
Explore your data
View and navigate all of your ledger information in one place with powerful, flexible tables.
Back-office operations
Perform back-office actions directly from the dashboard: create records, commit, or refund transactions, etc.
Generate custom insights
Stop building boring dashboards. With Insights, turn your ledger data into beautiful, interactive visualizations at a glance.
Managed deployment
Deploy your ledger infrastructure in one click
Run a production-ready ledger in one click. Same ledger engine, fully hosted, monitored, and maintained for you.
Start in Sandbox
Sandbox to production in one click
Explore with our sandbox and seamlessly switch to production whenever you're ready to go live.
Dedicated infrastructure
Your resources aren't shared. You get isolated compute and storage to handle up to 300,000 transactions per minute.
Automated backups
Enjoy up to 7-day backups with point in time recovery included for your ledger data.
Secure DB access
Your data isn't locked in. Deploy and safely connect to your hosted data whenever you need to.
The level of attention and dedication was exceptional. The support we got has been outstanding, and we couldn't ask for better partners.
Frequently
asked questions
Have other questions, send us an email at support@blnkfinance.com or contact us
Send us a message
What is Blnk Core?
Blnk Core is an open-source toolkit that gives developers everything they need to build ledgers, automate reconciliation, and manage identities with ease.
How does Blnk's ledger database work?
Blnk’s ledger is built on a double-entry accounting model designed for precision, scalability, and traceability. Each transaction is recorded as a balanced entry between a source and destination, ensuring data integrity at all times.
How does Blnk ensure double-entry consistency?
Blnk enforces double entry by requiring every transaction to have both a source and a destination. This means each transaction always involves two parties, keeping your records balanced.
Can Blnk Core handle multi-currency balances?
Yes. Blnk Core supports multi-currency by letting you define balances in different currencies and track them independently within the same ledger.
Can I model my own transaction workflows?
Yes, you can. Define how money moves in your system and implement them in Blnk via API calls. Blnk handles all of the ledger logic under the hood.
What's the performance like at scale (high-volume transactions)?
Blnk is designed to handle high volume transactions and workflows. Read our approach here.
Where does Blnk Core store my data?
Blnk core uses Postgres as it's storage engine. You get to bring your own Postgres database giving you 100% control on your data.
How do I connect Blnk Cloud to Blnk Core for insights and monitoring?
You connect your running Core instance to Blnk Cloud using our secure Query Agent. Learn how to connect your Core here.
How do I integrate Blnk into my existing stack?
Blnk is API-first. Run the open-source Core locally or in your infra, then connect through REST APIs or SDKs.
Can I extend Blnk with my own logic?
Yes. Everything in Blnk is driven by APIs. You can wrap workflows in your own services, extend them with business rules, or connect them to any provider.
Can I migrate my current ledger to Blnk Core?
Yes, you can. You can start by running Blnk alongside your current system. Import balances, replay historical transactions if needed, and phase over workflows step by step. Learn more about data migration here.
I have more questions. How do I get answers?
Send us a message at hello@blnkfinance.com or reach out to the team here.
