How to Create a Token Allowance Checker App

In this video, learn how to create a token allowance checker app to check for ERC20 token allowances for a wallet address. We do that by:
1. Getting filtered logs from QuickNode Streams in a Postgres database table.
2. Getting logs indexed according to wallet addresses in a separate table.
3. Have an express server talk to Postgres and a React app frontend that takes data from the express server.

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Get started with QuickNode Streams: https://qn.social/QNWebsite-allowance...
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Postgres provider Tembo: https://qn.social/QNTembo-allowance-c...

Streams filter code: https://qn.social/QNStreamfilter-allo...

pgSQL function code: https://qn.social/QNSql-allowance-che...

React app and express server code: https://qn.social/QNSample-allowance-...

QuickNode loves sharing its knowledge and tech with the community. Check out the following resources ♥:
Blog: https://qn.social/QNBlog-allowance-ch...
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RPC docs: https://qn.social/QNDocs-allowance-ch...
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00:00 Introduction
00:47 Steps we will follow
01:16 Create and connect to a Postgres instance
02:23 Create a Stream with a filter for allowance logs
13:08 Create another table in Postgres for indexed allowance data
14:31 Create and run a pgSQL function to get refined data from one table to another
19:27 React app and express server
27:14 Running the app locally
28:19 Outro