The three-way buying decision
This shortlist starts with Kernel and Steel, then includes Notte as a third implementation path for saved login reuse. A recurring job returns to the same website account in a later browser session. A stored profile must restore the intended user without assuming the website login is still valid.
Saved state can expire or be invalidated by the website. A profile save response establishes that data was stored, not that the next session is authenticated.
A proposed acceptance case
A recurring job returns to the same website account in a later browser session. A stored profile must restore the intended user without assuming the website login is still valid.
This is an evaluation design, not a claim that this workflow has been executed successfully on every provider.
| Part of the test | Required observation |
|---|---|
| Controlled input | An authorized account, its expected identity marker and two separately created browser sessions. |
| Pass condition | The second session reaches a protected page as the expected account after loading the target provider's saved-state resource. |
| Negative case | Invalidate the test website login between sessions. The workflow must detect the expired account state before performing the task. |
| Evidence to retain | Expected account, source and target state references, second-session identity and expired-login result. |
Documented mechanisms, side by side
These labels describe product mechanisms. The linked source and the acceptance case determine whether a mechanism meets this workflow's requirement.
| Requirement | Kernel | Steel | Notte |
|---|---|---|---|
| Saved browser state | Documented | Documented | Documented |
| Credential handling | Vaults (preview) | Credentials API | Documented |
| Website sign-in | Documented | Profile / credential flows | Documented |
Sources: kernel.sh [1] ↗kernel.sh [2] ↗docs.steel.dev [3] ↗docs.steel.dev [4] ↗docs.notte.cc [5] ↗docs.notte.cc [6] ↗
What survives a session
Kernel: Profiles preserve browser user-data-directory state, including cookies, site data, tabs and preferences. Profile sharing and save behavior need explicit treatment when parallel workers use seeded state.
Steel: The Profiles API documents reusable browser context, cookies, extensions, credentials and browser settings. Steel also documents lighter auth-context reuse, which should not be confused with a complete profile.
Notte: Profiles save cookies, local storage and session storage. Sessions start with fresh state by default. Persisting a profile writes state back when the session ends; a running session can also save its state explicitly.
Sources: kernel.sh [1] ↗docs.steel.dev [2] ↗docs.notte.cc [3] ↗
Website login
Kernel: Managed Auth handles website login and eligible connection recovery. Vault fill is a separate flow for applications that control navigation and form submission; the reviewed vault documentation labels that surface as preview.
Steel: Steel's Credentials API stores credentials for users or agents. Its cookbook demonstrates using stored credentials with Playwright, while profiles and auth contexts preserve signed-in browser state.
Notte: Vaults substitute credential placeholders in supported browser actions outside the model context. Managed Auth checks requested saved connections before automation. Personas supply an inbox and optional phone number for verification workflows.
Sources: kernel.sh [1] ↗docs.steel.dev [2] ↗docs.notte.cc [3] ↗
Pricing model
Kernel: Use the plan and browser configuration in Kernel's pricing documentation. Managed networking, account allowances and app execution make a browser-hour comparison only one part of the decision.
Steel: Hosted browser plans and a self-hosted browser have different cost structures. For self-hosting, include the worker, compute, networking, storage and operations rather than assigning the open-source code a zero operating cost.
Notte: The public usage rates are $0.01 per browser-hour, $0.05 per Function-hour and $10 per GB of managed proxy traffic. Paid plans return their price as usage credits. Price the relevant meters and plan eligibility for the workload.
What should change the choice?
Notte profiles are relevant for restoring cookies and web storage. Add its managed connection flow when the requirement includes login readiness rather than state restoration alone.
Kernel: Kernel's browser-local Apps make execution placement part of the decision. Compare the repeated action path with the proposed Notte controller or Function deployment before concluding that a lifecycle or hourly-rate difference decides the workflow.
Steel: Steel's managed and self-hosted choices make infrastructure ownership a concrete deciding factor. Keep that option on the shortlist when operating the browser is intentional; evaluate Notte when owning fewer execution and authentication components is the actual goal.
Keep a source profile or context integration when its documented storage behavior is essential and already verified. State should move only through a supported export/import contract or a fresh authorized login.
Sources: kernel.sh [1] ↗kernel.sh [2] ↗kernel.sh [3] ↗docs.steel.dev [4] ↗docs.steel.dev [5] ↗docs.steel.dev [6] ↗docs.notte.cc [7] ↗docs.notte.cc [8] ↗notte.cc [9] ↗
How to remove an option from the shortlist
For this workflow, require the following evidence from Kernel, Steel and Notte: Expected account, source and target state references, second-session identity and expired-login result.
Remove a proposed configuration when its documented mechanism or a controlled pilot cannot meet the pass condition. Keep an undocumented feature as an unresolved question instead of inventing an equivalence. Do not select a provider solely because it appears in this shortlist.
- The second session reaches a protected page as the expected account after loading the target provider's saved-state resource.
- Invalidate the test website login between sessions. The workflow must detect the expired account state before performing the task.
Sources: kernel.sh [1] ↗docs.steel.dev [2] ↗docs.notte.cc [3] ↗
Make a bounded pilot
Save state from an authorized login, start a separate session and verify the exact account on a protected page before running the task.
Use the same authorized account, input and final-state check in each configuration. Treat a missing product contract as an open question; do not turn an undocumented capability into an unsupported claim or a successful test result.
- Record the source account-to-profile mapping without treating its identifier as portable.
- Establish an authorized login in a target session and save it using the target profile contract.
- Verify the account in a second target session and in an expired-login test before changing recurring jobs.