diff --git a/src/application/ports/backend-client-port.ts b/src/application/ports/backend-client-port.ts
new file mode 100644
index 0000000..bb31894
--- /dev/null
+++ b/src/application/ports/backend-client-port.ts
@@ -0,0 +1,41 @@
+import { Context, Effect } from 'effect';
+import type {
+    GetMessageResponse,
+    TapCreditRequest,
+    TapCreditResponse,
+    UnderwriteRequest,
+    UnderwriteResponse,
+    VerifyMessageResponse,
+} from '../../domain/types/backend.js';
+
+/**
+ * Port for interacting with the Bulla backend API.
+ * Covers authentication, underwriting, and tap-credit flows.
+ */
+export interface BackendClientService {
+    /** GET /auth/{wallet}/getMessage — fetch SIWE challenge message. */
+    readonly getMessage: (wallet: string) => Effect.Effect<GetMessageResponse, Error>;
+
+    /** POST /auth/{wallet}/verifyMessage — submit signed message and receive JWT. */
+    readonly verifyMessage: (wallet: string, signature: string) => Effect.Effect<VerifyMessageResponse, Error>;
+
+    /** POST /underwrite/{wallet}/chain/{chainId}/pool/{poolAddress} — underwrite claims. */
+    readonly underwrite: (
+        authToken: string,
+        wallet: string,
+        chainId: number,
+        poolAddress: string,
+        body: UnderwriteRequest,
+    ) => Effect.Effect<UnderwriteResponse, Error>;
+
+    /** POST /tapCredit/batch/{wallet}/chain/{chainId}/pool/{poolAddress} — batch tap-credit. */
+    readonly tapCredit: (
+        authToken: string,
+        wallet: string,
+        chainId: number,
+        poolAddress: string,
+        body: TapCreditRequest,
+    ) => Effect.Effect<TapCreditResponse, Error>;
+}
+
+export const BackendClientService = Context.GenericTag<BackendClientService>('@services/BackendClientService');
diff --git a/src/cli/commands/factoring.ts b/src/cli/commands/factoring.ts
index bc6dbda..727fdc2 100644
--- a/src/cli/commands/factoring.ts
+++ b/src/cli/commands/factoring.ts
@@ -1,8 +1,9 @@
 import { Command } from '@effect/cli';
+import { backendCommands } from '../factoring/backend-commands.js';
 import { factoringCommands } from '../factoring/commands.js';
 import { factoringViewCommands, queueCommand } from '../factoring/view-commands.js';
 
 export const factoringCommand = Command.make('factoring', {}).pipe(
     Command.withDescription('Factoring pool operations'),
-    Command.withSubcommands([...factoringCommands, ...factoringViewCommands, queueCommand]),
+    Command.withSubcommands([...factoringCommands, ...factoringViewCommands, ...backendCommands, queueCommand]),
 );
diff --git a/src/cli/factoring/backend-commands.ts b/src/cli/factoring/backend-commands.ts
new file mode 100644
index 0000000..4dc6e55
--- /dev/null
+++ b/src/cli/factoring/backend-commands.ts
@@ -0,0 +1,160 @@
+import { Command } from '@effect/cli';
+import { readFileSync } from 'node:fs';
+import { Console, Effect } from 'effect';
+import { privateKeyToAccount } from 'viem/accounts';
+import { BackendClientService } from '../../application/ports/backend-client-port.js';
+import type { TapCreditRequestItem } from '../../domain/types/backend.js';
+import type { Hex } from '../../domain/types/eth.js';
+import { BackendClientLive } from '../../infrastructure/http/backend-client.js';
+import type { OutputFormat } from '../formatters/index.js';
+import { formatViewResult } from '../formatters/view.js';
+import { chainOption, formatOption } from '../options/common.js';
+import { getChainId } from '../options/common.js';
+import { authTokenOption, claimIdsOption, poolAddressOption, requestsFileOption } from '../options/factoring-options.js';
+import { privateKeyOption } from '../options/pay-options.js';
+
+// ============================================================================
+// HELPERS
+// ============================================================================
+
+/** Extract wallet address from a JWT token by decoding the base64 payload. */
+const extractWalletFromJwt = (token: string): string => {
+    const parts = token.split('.');
+    const payload = parts[1];
+    if (!payload) {
+        throw new Error('Invalid JWT: missing payload segment');
+    }
+    const decoded = JSON.parse(Buffer.from(payload, 'base64').toString()) as { wallet?: string };
+    if (!decoded.wallet) {
+        throw new Error('Invalid JWT: missing wallet field in payload');
+    }
+    return decoded.wallet;
+};
+
+// ============================================================================
+// AUTHENTICATE
+// ============================================================================
+
+const authenticateCommand = Command.make(
+    'authenticate',
+    {
+        privateKey: privateKeyOption,
+    },
+    ({ privateKey }) =>
+        Effect.gen(function* () {
+            const account = privateKeyToAccount(privateKey as Hex);
+            const wallet = account.address;
+
+            const client = yield* BackendClientService;
+
+            // Step 1: Get SIWE challenge message
+            const { message } = yield* client.getMessage(wallet);
+
+            // Step 2: Sign the message
+            const signature = yield* Effect.tryPromise({
+                try: () => account.signMessage({ message }),
+                catch: (err) => new Error(`Failed to sign message: ${err instanceof Error ? err.message : String(err)}`),
+            });
+
+            // Step 3: Verify and get JWT
+            const { message: token } = yield* client.verifyMessage(wallet, signature);
+
+            yield* Console.log(token);
+        }).pipe(Effect.provide(BackendClientLive)),
+).pipe(Command.withDescription('Authenticate with the Bulla backend and obtain a JWT token'));
+
+// ============================================================================
+// UNDERWRITE
+// ============================================================================
+
+const underwriteCommand = Command.make(
+    'underwrite',
+    {
+        authToken: authTokenOption,
+        poolAddress: poolAddressOption,
+        chain: chainOption,
+        claimIds: claimIdsOption,
+        format: formatOption,
+    },
+    ({ authToken, poolAddress, chain, claimIds, format }) =>
+        Effect.gen(function* () {
+            const wallet = extractWalletFromJwt(authToken);
+            const chainId = yield* getChainId(chain, undefined);
+
+            const client = yield* BackendClientService;
+            const claimIdList = claimIds.split(',').map(id => id.trim());
+
+            const response = yield* client.underwrite(authToken, wallet, chainId, poolAddress, {
+                claimIds: claimIdList,
+            });
+
+            for (const result of response.results) {
+                yield* Console.log(
+                    formatViewResult(
+                        {
+                            claimId: result.claimId,
+                            status: result.status,
+                            txHash: result.txHash,
+                            errors: result.errors.length > 0 ? result.errors.join(', ') : 'none',
+                        },
+                        format as OutputFormat,
+                    ),
+                );
+            }
+        }).pipe(Effect.provide(BackendClientLive)),
+).pipe(Command.withDescription('Underwrite claims via the Bulla backend'));
+
+// ============================================================================
+// TAP-CREDIT
+// ============================================================================
+
+const tapCreditCommand = Command.make(
+    'tap-credit',
+    {
+        authToken: authTokenOption,
+        poolAddress: poolAddressOption,
+        chain: chainOption,
+        requestsFile: requestsFileOption,
+        format: formatOption,
+    },
+    ({ authToken, poolAddress, chain, requestsFile, format }) =>
+        Effect.gen(function* () {
+            const wallet = extractWalletFromJwt(authToken);
+            const chainId = yield* getChainId(chain, undefined);
+
+            // Read and parse the requests file
+            const fileContent = yield* Effect.try({
+                try: () => readFileSync(requestsFile, 'utf-8'),
+                catch: (err) => new Error(`Failed to read requests file: ${err instanceof Error ? err.message : String(err)}`),
+            });
+
+            const requests = yield* Effect.try({
+                try: () => JSON.parse(fileContent) as readonly TapCreditRequestItem[],
+                catch: (err) => new Error(`Failed to parse requests file: ${err instanceof Error ? err.message : String(err)}`),
+            });
+
+            const client = yield* BackendClientService;
+
+            const response = yield* client.tapCredit(authToken, wallet, chainId, poolAddress, { requests });
+
+            for (const result of response.results) {
+                yield* Console.log(
+                    formatViewResult(
+                        {
+                            index: result.index,
+                            status: result.status,
+                            txHash: result.txHash,
+                            errors: result.errors.length > 0 ? result.errors.join(', ') : 'none',
+                        },
+                        format as OutputFormat,
+                    ),
+                );
+            }
+        }).pipe(Effect.provide(BackendClientLive)),
+).pipe(Command.withDescription('Batch tap-credit requests via the Bulla backend'));
+
+// ============================================================================
+// EXPORT
+// ============================================================================
+
+export const backendCommands = [authenticateCommand, underwriteCommand, tapCreditCommand] as const;
diff --git a/src/cli/options/factoring-options.ts b/src/cli/options/factoring-options.ts
index 0a64bac..d2aa410 100644
--- a/src/cli/options/factoring-options.ts
+++ b/src/cli/options/factoring-options.ts
@@ -44,3 +44,15 @@ export const poolTermLengthOption = Options.integer('term-length').pipe(Options.
 export const periodsPerYearOption = Options.integer('periods-per-year').pipe(
     Options.withDescription('Number of interest periods per year'),
 );
+
+export const authTokenOption = Options.text('auth-token').pipe(
+    Options.withDescription('JWT authentication token from the authenticate command'),
+);
+
+export const claimIdsOption = Options.text('claim-ids').pipe(
+    Options.withDescription('Comma-separated list of claim IDs to underwrite'),
+);
+
+export const requestsFileOption = Options.text('requests-file').pipe(
+    Options.withDescription('Path to JSON file containing tap-credit requests array'),
+);
diff --git a/src/domain/types/backend.ts b/src/domain/types/backend.ts
new file mode 100644
index 0000000..1c31efd
--- /dev/null
+++ b/src/domain/types/backend.ts
@@ -0,0 +1,55 @@
+// ============================================================================
+// Auth types
+// ============================================================================
+
+export interface GetMessageResponse {
+    readonly message: string;
+}
+
+export interface VerifyMessageResponse {
+    readonly message: string;
+}
+
+// ============================================================================
+// Underwrite types
+// ============================================================================
+
+export interface UnderwriteRequest {
+    readonly claimIds: readonly string[];
+}
+
+export interface UnderwriteResultItem {
+    readonly claimId: string;
+    readonly status: string;
+    readonly txHash: string;
+    readonly errors: readonly string[];
+}
+
+export interface UnderwriteResponse {
+    readonly results: readonly UnderwriteResultItem[];
+}
+
+// ============================================================================
+// Tap-credit types
+// ============================================================================
+
+export interface TapCreditRequestItem {
+    readonly description: string;
+    readonly dueBy: number;
+    readonly amount: string;
+}
+
+export interface TapCreditRequest {
+    readonly requests: readonly TapCreditRequestItem[];
+}
+
+export interface TapCreditResultItem {
+    readonly index: number;
+    readonly status: string;
+    readonly txHash: string;
+    readonly errors: readonly string[];
+}
+
+export interface TapCreditResponse {
+    readonly results: readonly TapCreditResultItem[];
+}
diff --git a/src/infrastructure/http/backend-client.ts b/src/infrastructure/http/backend-client.ts
new file mode 100644
index 0000000..a26f4dc
--- /dev/null
+++ b/src/infrastructure/http/backend-client.ts
@@ -0,0 +1,61 @@
+import { Effect, Layer } from 'effect';
+import { BackendClientService } from '../../application/ports/backend-client-port.js';
+import type {
+    GetMessageResponse,
+    TapCreditRequest,
+    TapCreditResponse,
+    UnderwriteRequest,
+    UnderwriteResponse,
+    VerifyMessageResponse,
+} from '../../domain/types/backend.js';
+
+const AUTH_BASE_URL = process.env.BULLA_AUTH_URL ?? 'https://apiauth.bulla.network';
+const UNDERWRITER_BASE_URL = process.env.BULLA_UW_URL ?? 'https://apiuw.bulla.network';
+
+const fetchJson = <T>(url: string, init?: RequestInit): Effect.Effect<T, Error> =>
+    Effect.tryPromise({
+        try: async () => {
+            const res = await fetch(url, init);
+            if (!res.ok) {
+                const body = await res.text().catch(() => '');
+                throw new Error(`HTTP ${res.status} from ${url}: ${body}`);
+            }
+            return (await res.json()) as T;
+        },
+        catch: (err) => (err instanceof Error ? err : new Error(String(err))),
+    });
+
+export const BackendClientLive = Layer.succeed(BackendClientService, {
+    getMessage: (wallet: string) =>
+        fetchJson<GetMessageResponse>(`${AUTH_BASE_URL}/auth/${wallet}/getMessage`),
+
+    verifyMessage: (wallet: string, signature: string) =>
+        fetchJson<VerifyMessageResponse>(`${AUTH_BASE_URL}/auth/${wallet}/verifyMessage`, {
+            method: 'POST',
+            headers: { 'Content-Type': 'text/plain' },
+            body: signature,
+        }),
+
+    underwrite: (authToken: string, wallet: string, chainId: number, poolAddress: string, body: UnderwriteRequest) =>
+        fetchJson<UnderwriteResponse>(`${UNDERWRITER_BASE_URL}/underwrite/${wallet}/chain/${chainId}/pool/${poolAddress}`, {
+            method: 'POST',
+            headers: {
+                'Authorization': `Bearer ${authToken}`,
+                'Content-Type': 'application/json',
+            },
+            body: JSON.stringify(body),
+        }),
+
+    tapCredit: (authToken: string, wallet: string, chainId: number, poolAddress: string, body: TapCreditRequest) =>
+        fetchJson<TapCreditResponse>(
+            `${UNDERWRITER_BASE_URL}/tapCredit/batch/${wallet}/chain/${chainId}/pool/${poolAddress}`,
+            {
+                method: 'POST',
+                headers: {
+                    'Authorization': `Bearer ${authToken}`,
+                    'Content-Type': 'application/json',
+                },
+                body: JSON.stringify(body),
+            },
+        ),
+});
diff --git a/test/cli/factoring/backend-commands.e2e.test.ts b/test/cli/factoring/backend-commands.e2e.test.ts
new file mode 100644
index 0000000..78e291f
--- /dev/null
+++ b/test/cli/factoring/backend-commands.e2e.test.ts
@@ -0,0 +1,323 @@
+import { createServer, type IncomingMessage, type Server, type ServerResponse } from 'node:http';
+import { writeFileSync, mkdirSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { describe, expect, it, beforeAll, afterAll } from 'vitest';
+import { privateKeyToAccount } from 'viem/accounts';
+import { recoverMessageAddress } from 'viem';
+import { runCli, runCliAsync } from '../../e2e/helpers/cli-runner.js';
+
+// ============================================================================
+// Test constants
+// ============================================================================
+
+const TEST_PRIVATE_KEY = '0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80'; // Hardhat #0
+const TEST_ACCOUNT = privateKeyToAccount(TEST_PRIVATE_KEY);
+const TEST_WALLET = TEST_ACCOUNT.address;
+const TEST_POOL = '0xa5e94f122d421c9579a5cb1e687f55e109ba270b';
+const TEST_CHAIN = '11155111';
+
+// Build a JWT with the test wallet so extractWalletFromJwt works
+const JWT_PAYLOAD = Buffer.from(JSON.stringify({ wallet: TEST_WALLET, exp: 9999999999 })).toString('base64');
+const FAKE_JWT = `eyJhbGciOiJIUzI1NiJ9.${JWT_PAYLOAD}.fake-signature`;
+
+// SIWE message the mock server will return
+const SIWE_MESSAGE = [
+    'Bulla Banker wants you to sign in with your Ethereum account:',
+    TEST_WALLET,
+    '',
+    'URI: https://banker.bulla.network/#/onboard',
+    'Version: 2',
+    'Nonce: 12345678',
+    'Chain ID: 1',
+    `Issued At: 2026-02-23T12:00:00.000Z`,
+].join('\n');
+
+// ============================================================================
+// Mock HTTP server
+// ============================================================================
+
+let mockServer: Server;
+let mockPort: number;
+let tmpDir: string;
+
+/** Read the full request body as a string. */
+const readBody = (req: IncomingMessage): Promise<string> =>
+    new Promise((resolve) => {
+        let data = '';
+        req.on('data', (chunk: Buffer) => (data += chunk.toString()));
+        req.on('end', () => resolve(data));
+    });
+
+/** Route handler for the mock backend. */
+const handleRequest = async (req: IncomingMessage, res: ServerResponse) => {
+    const url = req.url ?? '';
+    const method = req.method ?? 'GET';
+
+    // GET /auth/{wallet}/getMessage
+    if (method === 'GET' && url.match(/^\/auth\/0x[0-9a-fA-F]+\/getMessage$/)) {
+        res.writeHead(200, { 'Content-Type': 'application/json' });
+        res.end(JSON.stringify({ message: SIWE_MESSAGE }));
+        return;
+    }
+
+    // POST /auth/{wallet}/verifyMessage
+    if (method === 'POST' && url.match(/^\/auth\/0x[0-9a-fA-F]+\/verifyMessage$/)) {
+        const signature = await readBody(req);
+        const walletMatch = url.match(/\/auth\/(0x[0-9a-fA-F]+)\//);
+        const wallet = walletMatch?.[1] ?? '';
+
+        // Actually verify the SIWE signature
+        try {
+            const recovered = await recoverMessageAddress({
+                message: SIWE_MESSAGE,
+                signature: signature as `0x${string}`,
+            });
+            if (recovered.toLowerCase() !== wallet.toLowerCase()) {
+                res.writeHead(401, { 'Content-Type': 'application/json' });
+                res.end(JSON.stringify({ error: 'Signature mismatch' }));
+                return;
+            }
+        } catch {
+            res.writeHead(401, { 'Content-Type': 'application/json' });
+            res.end(JSON.stringify({ error: 'Invalid signature' }));
+            return;
+        }
+
+        // Return a JWT with the wallet in the payload
+        const payload = Buffer.from(JSON.stringify({ wallet, exp: 9999999999 })).toString('base64');
+        const jwt = `eyJhbGciOiJIUzI1NiJ9.${payload}.mock-signature`;
+        res.writeHead(200, { 'Content-Type': 'application/json' });
+        res.end(JSON.stringify({ message: jwt }));
+        return;
+    }
+
+    // POST /underwrite/{wallet}/chain/{chainId}/pool/{poolAddress}
+    if (method === 'POST' && url.match(/^\/underwrite\/0x[0-9a-fA-F]+\/chain\/\d+\/pool\/0x[0-9a-fA-F]+$/)) {
+        const body = JSON.parse(await readBody(req)) as { claimIds: string[] };
+        const results = body.claimIds.map((claimId) => ({
+            claimId,
+            status: 'Ok',
+            txHash: '0x' + 'ab'.repeat(32),
+            errors: [],
+        }));
+        res.writeHead(200, { 'Content-Type': 'application/json' });
+        res.end(JSON.stringify({ results }));
+        return;
+    }
+
+    // POST /tapCredit/batch/{wallet}/chain/{chainId}/pool/{poolAddress}
+    if (method === 'POST' && url.match(/^\/tapCredit\/batch\/0x[0-9a-fA-F]+\/chain\/\d+\/pool\/0x[0-9a-fA-F]+$/)) {
+        const body = JSON.parse(await readBody(req)) as { requests: unknown[] };
+        const results = body.requests.map((_, index) => ({
+            index,
+            status: 'Ok',
+            txHash: '0x' + 'cd'.repeat(32),
+            errors: [],
+        }));
+        res.writeHead(200, { 'Content-Type': 'application/json' });
+        res.end(JSON.stringify({ results }));
+        return;
+    }
+
+    res.writeHead(404, { 'Content-Type': 'application/json' });
+    res.end(JSON.stringify({ error: `Unknown route: ${method} ${url}` }));
+};
+
+/** Env vars that point the CLI at the mock server. */
+const mockEnv = () => ({
+    BULLA_AUTH_URL: `http://127.0.0.1:${mockPort}`,
+    BULLA_UW_URL: `http://127.0.0.1:${mockPort}`,
+});
+
+// ============================================================================
+// Setup / teardown
+// ============================================================================
+
+beforeAll(async () => {
+    tmpDir = join(tmpdir(), `bulla-cli-test-${Date.now()}`);
+    mkdirSync(tmpDir, { recursive: true });
+
+    mockServer = createServer((req, res) => {
+        handleRequest(req, res).catch(() => {
+            res.writeHead(500);
+            res.end();
+        });
+    });
+
+    await new Promise<void>((resolve) => {
+        mockServer.listen(0, '127.0.0.1', () => {
+            const addr = mockServer.address();
+            mockPort = typeof addr === 'object' && addr ? addr.port : 0;
+            resolve();
+        });
+    });
+});
+
+afterAll(async () => {
+    rmSync(tmpDir, { recursive: true, force: true });
+    await new Promise<void>((resolve) => mockServer.close(() => resolve()));
+});
+
+// ============================================================================
+// authenticate command
+// ============================================================================
+
+describe('factoring authenticate', () => {
+    it('fails when --private-key is missing', () => {
+        const result = runCli(['factoring', 'authenticate']);
+        expect(result.exitCode).toBeGreaterThanOrEqual(1);
+    });
+
+    it('authenticates successfully with a valid private key', async () => {
+        const result = await runCliAsync(
+            ['factoring', 'authenticate', '--private-key', TEST_PRIVATE_KEY],
+            mockEnv(),
+        );
+        expect(result.exitCode).toBe(0);
+        // The output should be a JWT (three dot-separated base64 segments)
+        expect(result.stdout).toMatch(/^[A-Za-z0-9_+/=-]+\.[A-Za-z0-9_+/=-]+\.[A-Za-z0-9_+/=-]+$/);
+
+        // Decode the JWT payload and verify the wallet
+        const payload = JSON.parse(Buffer.from(result.stdout.split('.')[1], 'base64').toString());
+        expect(payload.wallet.toLowerCase()).toBe(TEST_WALLET.toLowerCase());
+    });
+});
+
+// ============================================================================
+// underwrite command
+// ============================================================================
+
+describe('factoring underwrite', () => {
+    it('fails when --auth-token is missing', () => {
+        const result = runCli([
+            'factoring', 'underwrite', '--pool-address', TEST_POOL, '--chain', TEST_CHAIN, '--claim-ids', '1,2,3',
+        ]);
+        expect(result.exitCode).toBeGreaterThanOrEqual(1);
+    });
+
+    it('fails when --pool-address is missing', () => {
+        const result = runCli([
+            'factoring', 'underwrite', '--auth-token', FAKE_JWT, '--chain', TEST_CHAIN, '--claim-ids', '1,2,3',
+        ]);
+        expect(result.exitCode).toBeGreaterThanOrEqual(1);
+    });
+
+    it('fails when --claim-ids is missing', () => {
+        const result = runCli([
+            'factoring', 'underwrite', '--auth-token', FAKE_JWT, '--pool-address', TEST_POOL, '--chain', TEST_CHAIN,
+        ]);
+        expect(result.exitCode).toBeGreaterThanOrEqual(1);
+    });
+
+    it('fails with invalid JWT (no payload)', () => {
+        const result = runCli([
+            'factoring', 'underwrite', '--auth-token', 'not-a-jwt', '--pool-address', TEST_POOL,
+            '--chain', TEST_CHAIN, '--claim-ids', '1',
+        ]);
+        expect(result.exitCode).toBeGreaterThanOrEqual(1);
+    });
+
+    it('fails with JWT missing wallet field', () => {
+        const badPayload = Buffer.from(JSON.stringify({ exp: 999 })).toString('base64');
+        const badJwt = `header.${badPayload}.sig`;
+        const result = runCli([
+            'factoring', 'underwrite', '--auth-token', badJwt, '--pool-address', TEST_POOL,
+            '--chain', TEST_CHAIN, '--claim-ids', '1',
+        ]);
+        expect(result.exitCode).toBeGreaterThanOrEqual(1);
+    });
+
+    it('underwrites claims successfully', async () => {
+        const result = await runCliAsync(
+            [
+                'factoring', 'underwrite',
+                '--auth-token', FAKE_JWT,
+                '--pool-address', TEST_POOL,
+                '--chain', TEST_CHAIN,
+                '--claim-ids', '100,200,300',
+                '--format', 'json',
+            ],
+            mockEnv(),
+        );
+        expect(result.exitCode).toBe(0);
+
+        const output = result.stdout;
+        expect(output).toContain('"claimId": "100"');
+        expect(output).toContain('"claimId": "200"');
+        expect(output).toContain('"claimId": "300"');
+        expect(output).toContain('"status": "Ok"');
+        expect(output).toContain('"txHash"');
+    });
+});
+
+// ============================================================================
+// tap-credit command
+// ============================================================================
+
+describe('factoring tap-credit', () => {
+    it('fails when --auth-token is missing', () => {
+        const requestsFile = join(tmpDir, 'requests-noauth.json');
+        writeFileSync(requestsFile, JSON.stringify([{ description: 'test', dueBy: 1700000000, amount: '1000000' }]));
+        const result = runCli([
+            'factoring', 'tap-credit', '--pool-address', TEST_POOL, '--chain', TEST_CHAIN,
+            '--requests-file', requestsFile,
+        ]);
+        expect(result.exitCode).toBeGreaterThanOrEqual(1);
+    });
+
+    it('fails when --requests-file is missing', () => {
+        const result = runCli([
+            'factoring', 'tap-credit', '--auth-token', FAKE_JWT, '--pool-address', TEST_POOL, '--chain', TEST_CHAIN,
+        ]);
+        expect(result.exitCode).toBeGreaterThanOrEqual(1);
+    });
+
+    it('fails when requests file does not exist', () => {
+        const result = runCli([
+            'factoring', 'tap-credit', '--auth-token', FAKE_JWT, '--pool-address', TEST_POOL,
+            '--chain', TEST_CHAIN, '--requests-file', '/tmp/nonexistent-file-12345.json',
+        ]);
+        expect(result.exitCode).toBeGreaterThanOrEqual(1);
+    });
+
+    it('fails when requests file contains invalid JSON', () => {
+        const badFile = join(tmpDir, 'bad-requests.json');
+        writeFileSync(badFile, 'not valid json {{{');
+        const result = runCli([
+            'factoring', 'tap-credit', '--auth-token', FAKE_JWT, '--pool-address', TEST_POOL,
+            '--chain', TEST_CHAIN, '--requests-file', badFile,
+        ]);
+        expect(result.exitCode).toBeGreaterThanOrEqual(1);
+    });
+
+    it('processes tap-credit requests successfully', async () => {
+        const requestsFile = join(tmpDir, 'requests-ok.json');
+        writeFileSync(
+            requestsFile,
+            JSON.stringify([
+                { description: 'Invoice A', dueBy: 1700000000, amount: '1000000' },
+                { description: 'Invoice B', dueBy: 1700100000, amount: '2000000' },
+            ]),
+        );
+
+        const result = await runCliAsync(
+            [
+                'factoring', 'tap-credit',
+                '--auth-token', FAKE_JWT,
+                '--pool-address', TEST_POOL,
+                '--chain', TEST_CHAIN,
+                '--requests-file', requestsFile,
+                '--format', 'json',
+            ],
+            mockEnv(),
+        );
+        expect(result.exitCode).toBe(0);
+
+        const output = result.stdout;
+        expect(output).toContain('"index": 0');
+        expect(output).toContain('"index": 1');
+        expect(output).toContain('"status": "Ok"');
+        expect(output).toContain('"txHash"');
+    });
+});
diff --git a/test/e2e/helpers/cli-runner.ts b/test/e2e/helpers/cli-runner.ts
index c054a65..7c3165d 100644
--- a/test/e2e/helpers/cli-runner.ts
+++ b/test/e2e/helpers/cli-runner.ts
@@ -1,4 +1,4 @@
-import { spawnSync } from 'node:child_process';
+import { spawn, spawnSync } from 'node:child_process';
 import { resolve } from 'node:path';
 import { fileURLToPath } from 'node:url';
 
@@ -18,10 +18,11 @@ export interface TransactionOutput {
 }
 
 /** Run a bulla CLI command and return raw stdout/stderr/exitCode. */
-export function runCli(args: string[]): CliResult {
+export function runCli(args: string[], env?: Record<string, string>): CliResult {
     const result = spawnSync('node', [CLI_PATH, ...args], {
         encoding: 'utf-8',
         timeout: 60_000,
+        env: env ? { ...process.env, ...env } : undefined,
     });
     return {
         stdout: (result.stdout ?? '').trim(),
@@ -30,6 +31,24 @@ export function runCli(args: string[]): CliResult {
     };
 }
 
+/** Run a bulla CLI command asynchronously (non-blocking — allows in-process servers to respond). */
+export function runCliAsync(args: string[], env?: Record<string, string>): Promise<CliResult> {
+    return new Promise((resolve) => {
+        const child = spawn('node', [CLI_PATH, ...args], {
+            env: env ? { ...process.env, ...env } : undefined,
+            timeout: 30_000,
+        });
+
+        let stdout = '';
+        let stderr = '';
+        child.stdout.on('data', (chunk: Buffer) => (stdout += chunk.toString()));
+        child.stderr.on('data', (chunk: Buffer) => (stderr += chunk.toString()));
+        child.on('close', (code) => {
+            resolve({ stdout: stdout.trim(), stderr: stderr.trim(), exitCode: code ?? 1 });
+        });
+    });
+}
+
 /** Run a bulla CLI execute command with --format json and parse the TransactionOutput. */
 export function runCliExecute(args: string[]): TransactionOutput {
     const result = runCli([...args, '--format', 'json']);