Sandbox Relay vs Paytools
Price, ratings, monetisation and update history for both apps, side by side ā with what reviewers say about each.
Sandbox Relay
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For developers who run Claude Code or Codex in Docker Sandbox, Sandbox Relay is the phone client for driving that agent. It is a companion, not a standalone app: it needs a broker you run, with an agent connected behind it. Kick off a task from the train, check on a long-running job from the couch, or steer the agent while you are away from your desk. Docker Sandbox runs each agent in its own isolated micro VM. A small broker you self-host sits in the middle: you send work from your phone, the broker passes it to the agent, and the streamed reply comes back. Your infrastructure, your agent. The app is just the remote. New to this setup? The app's support page explains how it works and what you need to run it. WHAT YOU CAN DO - Connect to your broker with a URL and a bearer token. Connections use HTTPS, with plain HTTP allowed only for local-network addresses. - See every connected agent at a glance, with live online/offline status. - Send the agent work and watch its reply stream in token by token. Stop a turn mid-stream, or start a fresh thread whenever you want. - When an agent goes offline, its thread stays readable as history. - See per-turn input and output token counts when the broker reports them. - Save reusable prompts as local notes, organised by hierarchical tags like #work/project/feature. Drill down by tag, copy a note straight into a thread, or link a note to the thread it came from. Notes live on your device only; they never touch the broker. WHAT YOU NEED - A broker you run, reachable from your phone (over your local network, or remotely through a tunnel or private network you control). - A coding agent, Claude Code or Codex, running in Docker Sandbox and connected to that broker. PRIVACY Sandbox Relay talks only to the broker you configure. Your access token is stored securely on your device and sent only to that broker, to authenticate you; it never goes to the developer or any third party. Your notes stay on your device and are never sent anywhere. No third-party analytics, no account to create. Note that the app streams whatever your agent outputs, verbatim.
Paytools
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Paytools is an offline payment-engineering workbench for developers, QA engineers, integrators, students, and fintech teams. Decode and inspect common payment-message structures, explore field definitions, convert technical data, and keep essential payment references close at hand. Processing happens locally on your device, so pasted messages and imported files are not uploaded to a server. PAYMENT TOOLS ⢠Inspect ISO 8583 MTIs, bitmaps, and present data elements ⢠Decode and build primary and secondary bitmaps ⢠Parse BER-TLV data and identify common EMV tags ⢠Recognize SWIFT MT blocks and ISO 20022 XML messages ⢠Convert between HEX, ASCII, decimal, binary, and packed BCD ⢠Validate synthetic card numbers with the Luhn algorithm ⢠Compose synthetic Track 2 and ISO-0 PIN-block test data ⢠Use development utilities for XOR and DES odd parity KNOWLEDGE LIBRARY ⢠Search all 128 ISO 8583 data elements ⢠Learn ISO 8583:1987, 1993, and 2003 MTI concepts ⢠Follow authorization from merchant to acquirer, scheme, and issuer ⢠Understand STIP, advice, reversal, clearing, and settlement flows ⢠Review ISO 20022 message families and validation concepts ⢠Study EMV transaction and cryptogram terminology CODES AND FIELDS Search operational response-code references for common ISO profiles, Visa, Mastercard, UnionPay/UPI, 3-D Secure, and gateway HTTP outcomes. Open any ISO field for its purpose, format, and implementation notes, including an expanded guide to DE22 POS Entry Mode. PRIVATE BY DESIGN Paytools has no account requirement and no cloud processing. Use synthetic or appropriately masked test data. Production payment formats and code meanings can vary by network, region, product, and specification release. Paytools is an independent educational and development utility. It is not affiliated with or endorsed by any payment network. Formal certification and production processing require the current authorized specifications, test packs, approved cryptographic systems, and applicable security controls.
Screenshots
Verdict
Sandbox Relay and Paytools are too close to call on the numbers: across 5 compared parameters ā price, ads, in-app purchases and device support among them ā neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.
Scored on Price Ā· Rating Ā· Positive reviews Ā· Number of ratings Ā· Update frequency Ā· Ads Ā· In-app purchases Ā· Monetization Ā· Best chart rank Ā· Devices Ā· Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
| Parameter | Sandbox Relay | Paytools |
|---|---|---|
| Price | Free | Free |
| Update frequency | ā | Every 2 months |
| Ads | No | No |
| In-app purchases | No | No |
| Devices | iPhone | iPhone, iPad ā better |
| Requires iOS | 16.4 ā better | 17.0 |
| Further details ā not scored | ||
| Size | 32 MB | 4 MB |
| Age rating | 12+ | 4+ |
| Developer | Eric Boumendil | Emin Mammadov |
In-app purchases
Sandbox Relay
No in-app purchases
Paytools
No in-app purchases









