Banking APIs for developers

Joined February 2015
74 Photos and videos
Pinned Tweet
9 Jan 2025
🚨📢 In a head-to-head aggregator test performed by a large consumer fintech, Teller had the most stable connections. Number #2 disconnected 63% more often than Teller.
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Teller retweeted
Ok, enough talking. Introducing Wiretrap: Agentic Mobile App Reverse Engineering. @teller connects to over 7000 financial institutions, providing developers with a single API to integrate against. We connect using private APIs discovered by reverse engineering their mobile apps. This is a huge engineering cost (we have to analyze every app update to check for API changes), and obtaining accounts at those banks to be able to use their apps and map out the API interactions we need for our own API clients is an operational nightmare. Both are major blockers to supporting more institutions, countries, and product types, especially ones that are not practical to obtain at every bank, e.g. student loans and mortgages. Wiretrap solves for both problems. Wiretrap intercepts network requests a mobile app makes and injects symbolic responses that allow an agent to discover the underlying API contract by simply observing what the app does with them. It can override individual values to trigger different flows, allowing agents to completely map out an entire API without a single request hitting the bank. Check out this brief video of an agent using phony credentials to log into Chase (the request is intercepted by Wiretrap and never hits Chase's API) to get to the account dashboard. Note the symbolic value "req_058.response.body.bankingAccountOverviews[0]. businessName" displayed in the app UI, representing the request and key path the value originated from allowing the agent to join what is displayed on screen with what "went over the wire". Everything you see is inferred by observing how the app interacts with Wiretrap's symbolic responses. Another @teller world first :)
.@teller has a tool that can extract an API from any app AND build the SDK for it.
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Teller retweeted
.@teller has a tool that can extract an API from any app AND build the SDK for it.
Source: Anthropic is in advanced talks to acquire New York-based Stainless, which helps developers generate SDKs from APIs, for at least $300M (The Information) (Visit Techmeme dot com for the link and full context!)
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So far this new tool has worked on every app we’ve tested it with. Chase, Wells Fargo, BofA, Truist, a bunch of small provincial banks. After 5 months of smashing my head against the wall, to be honest I can’t quite believe it finally works. It works with everything, even stuff aggressively inlined by the compiler (standard on release swift apps). This is probably one the most important things I’ve built in my career.
Nobody will care but I’m reasonably confident that a tool I’ve been building is able to maintain all of the integrations we have at @teller. When a new app hits the AppStore, it reverses it in minutes. We’ve literally spent millions and millions of dollars on humans doing this over the years. Now we can do it faster and for orders of magnitude less cost. Also, for the first time ever we no longer need accounts at the financial institution. The whole analysis process happens offline. Two massive bottlenecks on our ability to scale have been obliterated. The really exciting question is: can it reverse all the other banks we haven’t done yet? Every bank in the world? Where is the limit?
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Teller retweeted
Nobody will care but I’m reasonably confident that a tool I’ve been building is able to maintain all of the integrations we have at @teller. When a new app hits the AppStore, it reverses it in minutes. We’ve literally spent millions and millions of dollars on humans doing this over the years. Now we can do it faster and for orders of magnitude less cost. Also, for the first time ever we no longer need accounts at the financial institution. The whole analysis process happens offline. Two massive bottlenecks on our ability to scale have been obliterated. The really exciting question is: can it reverse all the other banks we haven’t done yet? Every bank in the world? Where is the limit?
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Teller retweeted
Had fun with this & made an @openclaw skill that buys $1 of stock in every company you shop at @teller to hook into the bank account @public for market data & buy orders @CloudflareDev to host the connection flow & a daily summary Public is doing some awesome stuff github.com/DeanMauro/shop-to…
What would you build if your AI could execute real trades? Not paper trading. Real stocks, options, crypto. We just opened a 7-day skill-building contest. Best submission wins a Mac Mini. Compatible with Claude, Perplexity, OpenClaw, or roll your own. Show me what you've got → public.com/skills-challenge
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Imagine this was all you needed to fetch and display bank accounts from any bank in an iOS app. (Working code btw)
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15 Dec 2025
What's all this about then?
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Something new is coming…
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We (@teller) are shipping some incredible stuff this month. Stay tuned!
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The @teller team has been working on some really cool stuff these past few months and it’s going to fundamentally change how bank data aggregation is done. An unbelievable step change in user privacy is coming.
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29 Sep 2025
Experiment with @teller in Python, Ruby, Elixir, Go, Java, Node, or PHP with one command that bootstraps runtime env, installs dependencies and starts server github.com/tellerhq/examples
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9 Sep 2025
Testing something new…
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The industry continues to coalesce around the legal arguments we created at @teller in 2023.
In a letter to the CFPB, we outlined that community banks already meet the requirements of Section 1033 of the Dodd-Frank Act by providing consumers with electronic access to their financial data. See our letter: icba.org/advocacy/letter-det…
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25 Jun 2025
Powered by @teller! 🚀
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Woke up this morning to a customer asking if we could implement a feature and replies from the team saying it was done and in production. Brand new feature delivered from request in a little over 3 hours. What a great way to start my day. Incredible team we have at @teller
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26 May 2025
🙂‍↕️
ChatGPT has spoken
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7 May 2025
Between the CFPB revisiting it (possibly to rescind it altogether) and it facing a legal challenge in Federal Court, the Open Banking rule is almost certainly not going to survive the end of this year. Does it matter? Not if you’re a Teller customer. americanbanker.com/news/cfpb…
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