diff --git a/packages/appkit-react/src/features/onramp/widgets/crypto-onramp/utils/map-crypto-onramp-error.ts b/packages/appkit-react/src/features/onramp/widgets/crypto-onramp/utils/map-crypto-onramp-error.ts
index 07fa28d87..9c9767360 100644
--- a/packages/appkit-react/src/features/onramp/widgets/crypto-onramp/utils/map-crypto-onramp-error.ts
+++ b/packages/appkit-react/src/features/onramp/widgets/crypto-onramp/utils/map-crypto-onramp-error.ts
@@ -40,6 +40,8 @@ export const mapCryptoOnrampError = (error: unknown): string => {
                 return 'cryptoOnramp.quoteError';
             case CryptoOnrampErrorCode.ProviderError:
                 return 'cryptoOnramp.providerError';
+            case CryptoOnrampErrorCode.DepositFailed:
+                return 'cryptoOnramp.depositFailed';
         }
     }
 
diff --git a/packages/appkit-react/src/locales/en.ts b/packages/appkit-react/src/locales/en.ts
index ea491b10a..c26ef2626 100644
--- a/packages/appkit-react/src/locales/en.ts
+++ b/packages/appkit-react/src/locales/en.ts
@@ -112,6 +112,7 @@ export default {
         selectMethod: 'Select payment method',
         searchMethod: 'Search',
         quoteError: 'Failed to get a quote',
+        depositFailed: 'Failed to create deposit',
         tooManyDecimals: 'Too many decimals',
         providerError: 'Provider error',
         genericError: 'Something went wrong',
diff --git a/packages/walletkit/src/defi/DefiManager.ts b/packages/walletkit/src/defi/DefiManager.ts
index e94dc46aa..647dd463c 100644
--- a/packages/walletkit/src/defi/DefiManager.ts
+++ b/packages/walletkit/src/defi/DefiManager.ts
@@ -11,8 +11,7 @@ import type { DefiProvider } from '../api/interfaces';
 import { resolveProvider } from '../types';
 import type { ProviderInput } from '../types';
 import type { ProviderFactoryContext } from '../types/factory';
-import type { DefiError } from './errors';
-import { DefiErrorCode } from './errors';
+import { DefiError, DefiErrorCode } from './errors';
 import type { SharedKitEvents } from '../types/emitter';
 import type { EventEmitter } from '../core/EventEmitter';
 
@@ -24,7 +23,6 @@ export abstract class DefiManager<
 
     protected providers: T[] = [];
     protected defaultProviderId?: string;
-    protected abstract createError(message: string, code: string, details?: unknown): DefiError;
     protected eventEmitter: EventEmitter<E>;
 
     constructor(createFactoryContext: () => ProviderFactoryContext<E>) {
@@ -44,7 +42,7 @@ export abstract class DefiManager<
         const providerId = provider.providerId;
 
         if (!providerId) {
-            throw this.createError('Provider must have a providerId', DefiErrorCode.InvalidProvider);
+            throw new DefiError('Provider must have a providerId', DefiErrorCode.InvalidProvider);
         }
 
         const oldProvider = this.providers.find((p) => p.providerId === providerId);
@@ -84,7 +82,7 @@ export abstract class DefiManager<
         const provider = this.providers.find((p) => p.providerId === providerId);
 
         if (!provider) {
-            throw this.createError(`Provider '${providerId}' not found`, DefiErrorCode.ProviderNotFound, {
+            throw new DefiError(`Provider '${providerId}' not found`, DefiErrorCode.ProviderNotFound, {
                 provider: providerId,
                 registered: this.providers.map((p) => p.providerId),
             });
@@ -104,15 +102,12 @@ export abstract class DefiManager<
         const providerName = providerId || this.defaultProviderId;
 
         if (!providerName) {
-            throw this.createError(
-                'No default provider set. Register a provider first.',
-                DefiErrorCode.NoDefaultProvider,
-            );
+            throw new DefiError('No default provider set. Register a provider first.', DefiErrorCode.NoDefaultProvider);
         }
 
         const provider = this.providers.find((p) => p.providerId === providerName);
         if (!provider) {
-            throw this.createError(`Provider '${providerName}' not found`, DefiErrorCode.ProviderNotFound, {
+            throw new DefiError(`Provider '${providerName}' not found`, DefiErrorCode.ProviderNotFound, {
                 provider: providerName,
                 registered: this.providers.map((p) => p.providerId),
             });
diff --git a/packages/walletkit/src/defi/crypto-onramp/CryptoOnrampManager.ts b/packages/walletkit/src/defi/crypto-onramp/CryptoOnrampManager.ts
index 73fd5ab17..fc862188b 100644
--- a/packages/walletkit/src/defi/crypto-onramp/CryptoOnrampManager.ts
+++ b/packages/walletkit/src/defi/crypto-onramp/CryptoOnrampManager.ts
@@ -17,8 +17,7 @@ import type {
     CryptoOnrampStatusParams,
     CryptoOnrampSupportedCurrencies,
 } from '../../api/models';
-import type { CryptoOnrampErrorCode } from './errors';
-import { CryptoOnrampError } from './errors';
+import { CryptoOnrampError, CryptoOnrampErrorCode } from './errors';
 import { globalLogger } from '../../core/Logger';
 import { DefiManager } from '../DefiManager';
 
@@ -113,7 +112,12 @@ export class CryptoOnrampManager extends DefiManager<CryptoOnrampProviderInterfa
             return deposit;
         } catch (error) {
             log.error('Failed to create crypto onramp deposit', { error, params });
-            throw error;
+            if (error instanceof CryptoOnrampError) throw error;
+            throw new CryptoOnrampError(
+                'Failed to create crypto onramp deposit',
+                CryptoOnrampErrorCode.DepositFailed,
+                error,
+            );
         }
     }
 
@@ -160,8 +164,4 @@ export class CryptoOnrampManager extends DefiManager<CryptoOnrampProviderInterfa
             throw error;
         }
     }
-
-    protected createError(message: string, code: CryptoOnrampErrorCode, details?: unknown): CryptoOnrampError {
-        return new CryptoOnrampError(message, code, details);
-    }
 }
diff --git a/packages/walletkit/src/defi/crypto-onramp/errors.ts b/packages/walletkit/src/defi/crypto-onramp/errors.ts
index e805e5fc1..5de613c1e 100644
--- a/packages/walletkit/src/defi/crypto-onramp/errors.ts
+++ b/packages/walletkit/src/defi/crypto-onramp/errors.ts
@@ -11,6 +11,7 @@ import { DefiError } from '../errors';
 export enum CryptoOnrampErrorCode {
     ProviderError = 'PROVIDER_ERROR',
     QuoteFailed = 'QUOTE_FAILED',
+    DepositFailed = 'DEPOSIT_FAILED',
     RefundAddressRequired = 'REFUND_ADDRESS_REQUIRED',
     InvalidRefundAddress = 'INVALID_REFUND_ADDRESS',
     ReversedAmountNotSupported = 'REVERSED_AMOUNT_NOT_SUPPORTED',
diff --git a/packages/walletkit/src/defi/crypto-onramp/layerswap/LayerswapCryptoOnrampProvider.ts b/packages/walletkit/src/defi/crypto-onramp/layerswap/LayerswapCryptoOnrampProvider.ts
index 052b892c8..61da9cfef 100644
--- a/packages/walletkit/src/defi/crypto-onramp/layerswap/LayerswapCryptoOnrampProvider.ts
+++ b/packages/walletkit/src/defi/crypto-onramp/layerswap/LayerswapCryptoOnrampProvider.ts
@@ -26,13 +26,12 @@ import {
     DEFAULT_LAYERSWAP_SUPPORTED_CHAINS,
     LAYERSWAP_DESTINATION_NETWORK,
     LAYERSWAP_DESTINATION_TOKENS,
-    formatBaseUnits,
     isErrorResponse,
     mapLayerswapErrorCode,
     mapStatus,
-    parseBaseUnits,
 } from './utils';
 import type { LayerswapChainConfig } from './utils';
+import { formatUnits, parseUnits } from '../../../utils/units';
 
 const LAYERSWAP_API_URL = 'https://api.layerswap.io/api/v2';
 
@@ -145,7 +144,16 @@ export class LayerswapCryptoOnrampProvider extends CryptoOnrampProvider<undefine
             );
         }
 
-        const amountDecimal = formatBaseUnits(params.amount, sourceCurrency.decimals);
+        const baseUnits = BigInt(params.amount);
+
+        if (baseUnits < 0n) {
+            throw new CryptoOnrampError(
+                `Layerswap: amount "${params.amount}" is not a non-negative integer in base units`,
+                CryptoOnrampErrorCode.InvalidParams,
+            );
+        }
+
+        const amountDecimal = formatUnits(baseUnits, sourceCurrency.decimals);
 
         const body = {
             amount: amountDecimal,
@@ -198,7 +206,11 @@ export class LayerswapCryptoOnrampProvider extends CryptoOnrampProvider<undefine
             );
         }
 
-        const targetAmountBaseUnits = parseBaseUnits(data.quote.receive_amount, targetCurrency.decimals);
+        const targetAmountBaseUnits = parseUnits(
+            data.quote.receive_amount.toString(),
+            targetCurrency.decimals,
+        ).toString();
+
         const rate =
             data.quote.requested_amount > 0
                 ? (data.quote.receive_amount / data.quote.requested_amount).toString()
@@ -320,8 +332,10 @@ export class LayerswapCryptoOnrampProvider extends CryptoOnrampProvider<undefine
         );
 
         const sourceMap = new Map<string, CryptoOnrampSourceCurrency>();
+        let anyFulfilled = false;
         for (const result of results) {
             if (result.status !== 'fulfilled') continue;
+            anyFulfilled = true;
             for (const network of result.value) {
                 const caip2 = slugToCaip2[network.name];
                 if (!caip2) continue;
@@ -334,6 +348,17 @@ export class LayerswapCryptoOnrampProvider extends CryptoOnrampProvider<undefine
             }
         }
 
+        if (!anyFulfilled && results.length > 0) {
+            const firstRejection = results.find(
+                (result): result is PromiseRejectedResult => result.status === 'rejected',
+            );
+            throw new CryptoOnrampError(
+                'Layerswap: failed to fetch supported sources for all destinations',
+                CryptoOnrampErrorCode.ProviderError,
+                firstRejection?.reason,
+            );
+        }
+
         return { source: Array.from(sourceMap.values()), destination };
     }
 
diff --git a/packages/walletkit/src/defi/crypto-onramp/layerswap/utils.ts b/packages/walletkit/src/defi/crypto-onramp/layerswap/utils.ts
index e7552d99b..11004f111 100644
--- a/packages/walletkit/src/defi/crypto-onramp/layerswap/utils.ts
+++ b/packages/walletkit/src/defi/crypto-onramp/layerswap/utils.ts
@@ -129,33 +129,3 @@ export const mapStatus = (status: LayerswapSwapStatus | string): CryptoOnrampSta
             return 'pending';
     }
 };
-
-/**
- * Format a base-units integer string into a decimal token-units string.
- * e.g. formatBaseUnits('2000000', 6) === '2'
- */
-export const formatBaseUnits = (base: string, decimals: number): string => {
-    if (!/^\d+$/.test(base)) {
-        throw new Error(`formatBaseUnits: not a non-negative integer string: "${base}"`);
-    }
-    if (decimals === 0) return base;
-    const padded = base.padStart(decimals + 1, '0');
-    const whole = padded.slice(0, padded.length - decimals);
-    const frac = padded.slice(padded.length - decimals).replace(/0+$/, '');
-    return frac.length > 0 ? `${whole}.${frac}` : whole;
-};
-
-/**
- * Scale a decimal token-units string by 10^decimals and return the integer
- * base-units string, truncating any excess fractional digits.
- */
-export const parseBaseUnits = (value: number | string, decimals: number): string => {
-    const str = typeof value === 'number' ? value.toString() : value;
-    if (!/^\d+(\.\d+)?$/.test(str)) {
-        throw new Error(`parseBaseUnits: not a non-negative decimal: "${str}"`);
-    }
-    const [whole, frac = ''] = str.split('.');
-    const truncated = frac.slice(0, decimals).padEnd(decimals, '0');
-    const combined = `${whole}${truncated}`.replace(/^0+/, '');
-    return combined.length > 0 ? combined : '0';
-};
diff --git a/packages/walletkit/src/defi/onramp/OnrampManager.ts b/packages/walletkit/src/defi/onramp/OnrampManager.ts
index 822f7fcf9..3e135db11 100644
--- a/packages/walletkit/src/defi/onramp/OnrampManager.ts
+++ b/packages/walletkit/src/defi/onramp/OnrampManager.ts
@@ -8,7 +8,6 @@
 
 import type { OnrampAPI, OnrampProviderInterface } from '../../api/interfaces';
 import type { OnrampParams, OnrampQuote, OnrampQuoteParams } from '../../api/models';
-import { OnrampError } from './errors';
 import { globalLogger } from '../../core/Logger';
 import { DefiManager } from '../DefiManager';
 
@@ -124,8 +123,4 @@ export class OnrampManager extends DefiManager<OnrampProviderInterface> implemen
             throw error;
         }
     }
-
-    protected createError(message: string, code: string, details?: unknown): OnrampError {
-        return new OnrampError(message, code, details);
-    }
 }
diff --git a/packages/walletkit/src/defi/onramp/errors.ts b/packages/walletkit/src/defi/onramp/errors.ts
index 337e919a7..a83067073 100644
--- a/packages/walletkit/src/defi/onramp/errors.ts
+++ b/packages/walletkit/src/defi/onramp/errors.ts
@@ -8,14 +8,19 @@
 
 import { DefiError } from '../errors';
 
+export enum OnrampErrorCode {
+    ProviderError = 'PROVIDER_ERROR',
+    InvalidParams = 'INVALID_ONRAMP_PARAMS',
+    QuoteFailed = 'QUOTE_FAILED',
+    UrlBuildFailed = 'URL_BUILD_FAILED',
+}
+
 export class OnrampError extends DefiError {
-    static readonly PROVIDER_ERROR = 'PROVIDER_ERROR';
-    static readonly InvalidParams = 'INVALID_ONRAMP_PARAMS';
-    static readonly QUOTE_FAILED = 'QUOTE_FAILED';
-    static readonly URL_BUILD_FAILED = 'URL_BUILD_FAILED';
+    public readonly code: OnrampErrorCode;
 
-    constructor(message: string, code: string, details?: unknown) {
+    constructor(message: string, code: OnrampErrorCode, details?: unknown) {
         super(message, code, details);
         this.name = 'OnrampError';
+        this.code = code;
     }
 }
diff --git a/packages/walletkit/src/defi/onramp/mercuryo/MercuryoProvider.ts b/packages/walletkit/src/defi/onramp/mercuryo/MercuryoProvider.ts
index d18c9f15e..ec7974c69 100644
--- a/packages/walletkit/src/defi/onramp/mercuryo/MercuryoProvider.ts
+++ b/packages/walletkit/src/defi/onramp/mercuryo/MercuryoProvider.ts
@@ -9,7 +9,7 @@
 import type { OnrampParams, OnrampQuote, OnrampQuoteParams } from '../../../api/models';
 import { Network } from '../../../api/models';
 import { OnrampProvider } from '../OnrampProvider';
-import { OnrampError } from '../errors';
+import { OnrampError, OnrampErrorCode } from '../errors';
 
 /**
  * Custom options for Mercuryo requests
@@ -101,7 +101,7 @@ export class MercuryoProvider extends OnrampProvider<MercuryoQuoteOptions, Mercu
                 metadata: data.data,
             };
         } catch (error) {
-            throw new OnrampError('Failed to get Mercuryo quote', OnrampError.QUOTE_FAILED, error);
+            throw new OnrampError('Failed to get Mercuryo quote', OnrampErrorCode.QuoteFailed, error);
         }
     }
 
@@ -134,7 +134,7 @@ export class MercuryoProvider extends OnrampProvider<MercuryoQuoteOptions, Mercu
 
             return url.toString();
         } catch (error) {
-            throw new OnrampError('Failed to build Mercuryo URL', OnrampError.URL_BUILD_FAILED, error);
+            throw new OnrampError('Failed to build Mercuryo URL', OnrampErrorCode.UrlBuildFailed, error);
         }
     }
 }
diff --git a/packages/walletkit/src/defi/onramp/moonpay/MoonpayProvider.ts b/packages/walletkit/src/defi/onramp/moonpay/MoonpayProvider.ts
index b37714b81..6b34993f0 100644
--- a/packages/walletkit/src/defi/onramp/moonpay/MoonpayProvider.ts
+++ b/packages/walletkit/src/defi/onramp/moonpay/MoonpayProvider.ts
@@ -9,7 +9,7 @@
 import type { OnrampParams, OnrampQuote, OnrampQuoteParams } from '../../../api/models';
 import { Network } from '../../../api/models';
 import { OnrampProvider } from '../OnrampProvider';
-import { OnrampError } from '../errors';
+import { OnrampError, OnrampErrorCode } from '../errors';
 
 /**
  * Custom options for Moonpay requests
@@ -48,7 +48,7 @@ export class MoonpayProvider extends OnrampProvider<MoonpayQuoteOptions, Moonpay
     constructor(apiKey: string) {
         super();
         if (!apiKey) {
-            throw new OnrampError('Moonpay API key is required', OnrampError.PROVIDER_ERROR);
+            throw new OnrampError('Moonpay API key is required', OnrampErrorCode.ProviderError);
         }
         this.apiKey = apiKey;
     }
@@ -89,7 +89,7 @@ export class MoonpayProvider extends OnrampProvider<MoonpayQuoteOptions, Moonpay
                 metadata: data,
             };
         } catch (error) {
-            throw new OnrampError('Failed to get Moonpay quote', OnrampError.QUOTE_FAILED, error);
+            throw new OnrampError('Failed to get Moonpay quote', OnrampErrorCode.QuoteFailed, error);
         }
     }
 
@@ -116,7 +116,7 @@ export class MoonpayProvider extends OnrampProvider<MoonpayQuoteOptions, Moonpay
 
             return url.toString();
         } catch (error) {
-            throw new OnrampError('Failed to build Moonpay URL', OnrampError.URL_BUILD_FAILED, error);
+            throw new OnrampError('Failed to build Moonpay URL', OnrampErrorCode.UrlBuildFailed, error);
         }
     }
 }
diff --git a/packages/walletkit/src/defi/onramp/ton-pay/TonPayProvider.ts b/packages/walletkit/src/defi/onramp/ton-pay/TonPayProvider.ts
index 4b094eb44..faae40447 100644
--- a/packages/walletkit/src/defi/onramp/ton-pay/TonPayProvider.ts
+++ b/packages/walletkit/src/defi/onramp/ton-pay/TonPayProvider.ts
@@ -9,7 +9,7 @@
 import type { OnrampParams, OnrampQuote, OnrampQuoteParams } from '../../../api/models';
 import { Network } from '../../../api/models';
 import { OnrampProvider } from '../OnrampProvider';
-import { OnrampError } from '../errors';
+import { OnrampError, OnrampErrorCode } from '../errors';
 
 /**
  * Custom options for TonPay requests
@@ -79,7 +79,7 @@ export class TonPayProvider extends OnrampProvider<TonPayQuoteOptions, TonPayOnr
                 metadata: data,
             };
         } catch (error) {
-            throw new OnrampError('Failed to get TonPay quote', OnrampError.QUOTE_FAILED, error);
+            throw new OnrampError('Failed to get TonPay quote', OnrampErrorCode.QuoteFailed, error);
         }
     }
 
@@ -117,7 +117,7 @@ export class TonPayProvider extends OnrampProvider<TonPayQuoteOptions, TonPayOnr
 
             return data.link;
         } catch (error) {
-            throw new OnrampError('Failed to build TonPay URL', OnrampError.URL_BUILD_FAILED, error);
+            throw new OnrampError('Failed to build TonPay URL', OnrampErrorCode.UrlBuildFailed, error);
         }
     }
 }
diff --git a/packages/walletkit/src/defi/staking/StakingManager.ts b/packages/walletkit/src/defi/staking/StakingManager.ts
index d8dd51b9a..1d344aee6 100644
--- a/packages/walletkit/src/defi/staking/StakingManager.ts
+++ b/packages/walletkit/src/defi/staking/StakingManager.ts
@@ -46,7 +46,7 @@ export class StakingManager extends DefiManager<StakingProviderInterface> implem
             log.debug('Received staking quote', quote);
             return quote;
         } catch (error) {
-            throw this.createError('Failed to get staking quote', StakingErrorCode.InvalidParams, { error, params });
+            throw new StakingError('Failed to get staking quote', StakingErrorCode.InvalidParams, { error, params });
         }
     }
 
@@ -60,7 +60,7 @@ export class StakingManager extends DefiManager<StakingProviderInterface> implem
         try {
             return await this.getProvider(providerId).buildStakeTransaction(params);
         } catch (error) {
-            throw this.createError('Failed to build staking transaction', StakingErrorCode.InvalidParams, {
+            throw new StakingError('Failed to build staking transaction', StakingErrorCode.InvalidParams, {
                 error,
                 params,
             });
@@ -87,7 +87,7 @@ export class StakingManager extends DefiManager<StakingProviderInterface> implem
         try {
             return await this.getProvider(providerId).getStakedBalance(userAddress, network);
         } catch (error) {
-            throw this.createError('Failed to get staking balance', StakingErrorCode.InvalidParams, {
+            throw new StakingError('Failed to get staking balance', StakingErrorCode.InvalidParams, {
                 error,
                 userAddress,
                 network,
@@ -109,7 +109,7 @@ export class StakingManager extends DefiManager<StakingProviderInterface> implem
         try {
             return await this.getProvider(providerId).getStakingProviderInfo(network);
         } catch (error) {
-            throw this.createError('Failed to get staking info', StakingErrorCode.InvalidParams, { error, network });
+            throw new StakingError('Failed to get staking info', StakingErrorCode.InvalidParams, { error, network });
         }
     }
 
@@ -127,18 +127,10 @@ export class StakingManager extends DefiManager<StakingProviderInterface> implem
         try {
             return this.getProvider(providerId).getStakingProviderMetadata(network);
         } catch (error) {
-            throw this.createError('Failed to get staking metadata', StakingErrorCode.InvalidParams, {
+            throw new StakingError('Failed to get staking metadata', StakingErrorCode.InvalidParams, {
                 error,
                 network,
             });
         }
     }
-
-    protected createError(message: string, code: string, details?: unknown): StakingError {
-        const errorCode = Object.values(StakingErrorCode).includes(code as StakingErrorCode)
-            ? (code as StakingErrorCode)
-            : StakingErrorCode.InvalidParams;
-        log.error(message, { code, details });
-        return new StakingError(message, errorCode, details);
-    }
 }
diff --git a/packages/walletkit/src/defi/swap/SwapManager.ts b/packages/walletkit/src/defi/swap/SwapManager.ts
index 3ae1da73a..7b738d44f 100644
--- a/packages/walletkit/src/defi/swap/SwapManager.ts
+++ b/packages/walletkit/src/defi/swap/SwapManager.ts
@@ -9,8 +9,6 @@
 import type { TransactionRequest } from '../../api/models';
 import type { SwapAPI, SwapProviderInterface } from '../../api/interfaces';
 import type { SwapQuoteParams, SwapQuote, SwapParams } from '../../api/models';
-import type { SwapErrorCode } from './errors';
-import { SwapError } from './errors';
 import { globalLogger } from '../../core/Logger';
 import { DefiManager } from '../DefiManager';
 import type { ProviderFactoryContext } from '../../types/factory';
@@ -88,8 +86,4 @@ export class SwapManager extends DefiManager<SwapProviderInterface> implements S
             throw error;
         }
     }
-
-    protected createError(message: string, code: string, details?: unknown): SwapError {
-        return new SwapError(message, code as SwapErrorCode, details);
-    }
 }
diff --git a/packages/walletkit/src/index.ts b/packages/walletkit/src/index.ts
index b96a68a30..a553750c4 100644
--- a/packages/walletkit/src/index.ts
+++ b/packages/walletkit/src/index.ts
@@ -22,7 +22,7 @@ export { JettonsManager } from './core/JettonsManager';
 export { DefiError, DefiErrorCode } from './defi/errors';
 export { SwapManager, SwapProvider, SwapError, SwapErrorCode } from './defi/swap';
 export { StakingManager, StakingProvider, StakingError, StakingErrorCode } from './defi/staking';
-export { OnrampManager, OnrampProvider, OnrampError } from './defi/onramp';
+export { OnrampManager, OnrampProvider, OnrampError, OnrampErrorCode } from './defi/onramp';
 export {
     CryptoOnrampManager,
     CryptoOnrampProvider,