KYC Integration Hell: Why One Fintech Waited 3 Months and Gained 40MB

TL;DR

A fintech developer recently sparked a revealing discussion on Reddit after their team spent three months integrating a KYC (Know Your Customer) solution—only to see their mobile app bloat by 40MB in the process. The post highlights a widespread problem in the fintech development world: compliance vendors that bundle heavyweight SDKs, lack proper documentation, and drag out implementation timelines. The community’s response reveals this isn’t an isolated incident—it’s practically an industry standard that needs disrupting.

What the Sources Say

The original post comes from Reddit’s r/fintech community, where a frustrated developer asked whether their experience was normal. The question resonated: the thread accumulated 15 comments and sparked candid conversations about the state of KYC integration in 2026.

The Core Problem

According to the original poster, their integration journey hit two major pain points:

1. Timeline bloat: Three months from start to finish for what should theoretically be a straightforward API integration
2. App size explosion: A 40MB increase to their mobile app’s footprint—enough to make users on limited data plans think twice about downloading

The Reddit community’s consensus? Yes, this is depressingly normal. Multiple commenters confirmed they’d experienced similar or worse integration nightmares with various KYC providers.

Why KYC Integrations Take So Long

The discussion revealed several recurring culprits:

• Heavyweight SDKs: Many KYC vendors ship monolithic SDKs packed with features most apps never use. One commenter noted that some providers bundle entire document scanning libraries, liveness detection frameworks, and OCR engines—even if you only need basic ID verification.

• Poor documentation: Several developers mentioned spending weeks deciphering incomplete API docs or outdated integration guides. One noted their vendor’s documentation referenced deprecated endpoints that had been sunset months earlier.

• Compliance complexity: KYC isn’t just technical—it’s regulatory. Some of the timeline gets eaten by legal review, understanding jurisdiction-specific requirements, and ensuring your implementation meets standards like GDPR, AML directives, or specific financial regulations in your target markets.

• Vendor responsiveness: Multiple commenters cited slow support responses as a bottleneck. One shared they waited two weeks for clarification on a single API parameter.

The 40MB Elephant in the Room

The app size increase generated particular frustration. In mobile development, every megabyte matters:

• Users on metered connections may avoid downloading large apps
• iOS App Store guidelines warn about large binaries
• Android’s instant apps feature has strict size limits
• Emerging markets with slower networks are disproportionately affected

Community members suggested the bloat likely comes from:

• Embedded ML models for face matching and liveness detection
• Multiple architecture support (ARM, x86) without proper binary slicing
• Redundant image processing libraries
• Localization resources for dozens of languages (even if your app only supports a few)

Contradictions and Nuance

Not everyone agreed the situation was purely the vendor’s fault. A few commenters noted:

• Security trade-offs: Some argued that heavier SDKs might justify their size with better fraud prevention. One developer mentioned their 50MB KYC SDK caught synthetic identity fraud their previous lightweight solution missed.

• Feature creep: Another commenter suggested the original poster might have opted into features they didn’t strictly need. “Did you really need the selfie video liveness check, or would a simple photo + document scan have worked?” one asked.

• Implementation choices: One experienced developer pointed out that some vendors offer both SDK-based and API-only integration paths. The API route typically keeps your app lighter but shifts more UI/UX responsibility to your team.

Alternative Approaches Mentioned

The thread included suggestions for avoiding this pain:

• Modular vendors: Some newer KYC providers (not specifically named in the thread) let you cherry-pick features, potentially reducing SDK size
• Web-based flows: Handling KYC in a mobile web view instead of native code can keep your core app lean
• Progressive integration: Start with basic verification and add advanced features (like biometric checks) only after the user has demonstrated engagement with your app

Pricing & Alternatives

The Reddit thread didn’t dive deep into specific pricing or vendor comparisons—likely because discussing contract details publicly can violate NDAs. However, the community discussion revealed some general patterns:

Typical KYC Pricing Models (2026)

One commenter noted their tier 1 vendor charged $1.20 per verification but the actual cost climbed to nearly $2.50 when factoring in failed attempts, retries, and support tickets needed to resolve edge cases.

Trade-offs to Consider

The discussion highlighted that choosing a KYC vendor isn’t just about price:

According to the thread, there’s no clear winner—it depends on your startup stage, target market, and risk tolerance.

The Bottom Line: Who Should Care?

If you’re building a fintech app in 2026, this Reddit thread is required reading. Here’s why:

Early-stage founders: Budget 2-3x more time than the KYC vendor’s sales team promises. One commenter suggested: “If they say 4 weeks, plan for 12.” That might sound cynical, but multiple developers confirmed it matches reality.

Mobile developers: Advocate loudly against SDK bloat. Ask vendors during the sales process:

• What’s the actual size impact per platform?
• Can we integrate via API instead of SDK?
• Which features can we disable to reduce binary size?
• Do you support dynamic feature loading?

Product managers: Understand that KYC isn’t a “set and forget” integration. Regulations change, vendors update their APIs, and fraud patterns evolve. One commenter mentioned they now allocate one sprint per quarter just for KYC maintenance.

Startup CTOs: Consider KYC a major technical decision on par with choosing your cloud provider or database. The wrong choice can handicap your app’s performance and drain engineering resources for months. Several commenters wished they’d done a more thorough proof-of-concept before signing contracts.

The Bigger Picture

This discussion reflects a broader tension in fintech: the compliance burden is necessary and important (nobody wants their app used for money laundering), but the tooling hasn’t caught up with modern mobile development best practices.

As one commenter eloquently summarized: “KYC vendors are still living in a 2015 world where a 100MB app was acceptable. In 2026, with 5G networks in developed markets but billions still on 3G/4G, and with progressive web apps setting expectations for lightning-fast experiences, a 40MB bloat for compliance is unacceptable.”

The good news? The fact that developers are publicly pushing back means vendors will eventually have to modernize. The bad news? If you’re integrating KYC this quarter, you’re probably still stuck with the 2015-era solutions.

Action Items

Before your next KYC integration:

1. Request a technical deep-dive demo: Don’t settle for a sales pitch. Have your mobile team evaluate the actual SDK.

2. Test with real devices: Download their example app on a 3-year-old Android phone with a slow connection. If it’s painful, your users will feel it too.

3. Negotiate staging environments: Several commenters mentioned vendors that charge for sandbox usage or provide limited test credentials, which slows development.

4. Plan for the worst: Triple the vendor’s timeline estimate and budget engineering resources accordingly.

5. Document everything: One developer shared they created an internal wiki documenting every quirk, workaround, and gotcha. Six months later, it saved them weeks when onboarding a new team member.

The KYC integration journey might be painful in 2026, but at least you’re not alone—an entire community of fintech developers is fighting the same battle.

Sources

• KYC integration is taking 3 months and our mobile app gained 40MB. Is this normal? - Reddit r/fintech discussion with 15 community responses